Using the GNU Privacy Guard

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This is the The GNU Privacy Guard Manual (version 2.3.4, December 2021).

© 2002, 2004, 2005, 2006, 2007, 2010 Free Software Foundation, Inc.
© 2013, 2014, 2015 Werner Koch.
© 2015, 2016, 2017 g10 Code GmbH.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. The text of the license can be found in the section entitled “Copying”.

This manual documents how to use the GNU Privacy Guard system as well as the administration and the architecture.

Table of Contents

Short Table of Contents


1 A short installation guide

Unfortunately the installation guide has not been finished in time. Instead of delaying the release of GnuPG 2.0 even further, I decided to release without that guide. The chapter on gpg-agent and gpgsm do include brief information on how to set up the whole thing. Please watch the GnuPG website for updates of the documentation. In the meantime you may search the GnuPG mailing list archives or ask on the gnupg-users mailing list for advise on how to solve problems or how to get that whole thing up and running.

** Building the software

Building the software is described in the file INSTALL. Given that you are already reading this documentation we can only give some extra hints.

To comply with the rules on GNU systems you should have build time configured gnupg using:

./configure --sysconfdir=/etc --localstatedir=/var

This is to make sure that system wide configuration files are searched in the directory /etc and variable data below /var; the default would be to also install them below /usr/local where the binaries get installed. If you selected to use the --prefix=/ you obviously don’t need those option as they are the default then.

** Notes on setting a root CA key to trusted

X.509 is based on a hierarchical key infrastructure. At the root of the tree a trusted anchor (root certificate) is required. There are usually no other means of verifying whether this root certificate is trustworthy than looking it up in a list. GnuPG uses a file (trustlist.txt) to keep track of all root certificates it knows about. There are 3 ways to get certificates into this list:


2 Invoking GPG-AGENT

gpg-agent is a daemon to manage secret (private) keys independently from any protocol. It is used as a backend for gpg and gpgsm as well as for a couple of other utilities.

The agent is automatically started on demand by gpg, gpgsm, gpgconf, or gpg-connect-agent. Thus there is no reason to start it manually. In case you want to use the included Secure Shell Agent you may start the agent using:

gpg-connect-agent /bye

If you want to manually terminate the currently-running agent, you can safely do so with:

gpgconf --kill gpg-agent

You should always add the following lines to your .bashrc or whatever initialization file is used for all shell invocations:

GPG_TTY=$(tty)
export GPG_TTY

It is important that this environment variable always reflects the output of the tty command. For W32 systems this option is not required.

Please make sure that a proper pinentry program has been installed under the default filename (which is system dependent) or use the option pinentry-program to specify the full name of that program. It is often useful to install a symbolic link from the actual used pinentry (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/bin/pinentry-gtk) to the expected one (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/bin/pinentry).

See Option Index, for an index to GPG-AGENT’s commands and options.


2.1 Commands

Commands are not distinguished from options except for the fact that only one command is allowed.

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help
-h

Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command.

--dump-options

Print a list of all available options and commands. Note that you cannot abbreviate this command.

--server

Run in server mode and wait for commands on the stdin. The default mode is to create a socket and listen for commands there.

--daemon [command line]

Start the gpg-agent as a daemon; that is, detach it from the console and run it in the background.

As an alternative you may create a new process as a child of gpg-agent: gpg-agent --daemon /bin/sh. This way you get a new shell with the environment setup properly; after you exit from this shell, gpg-agent terminates within a few seconds.

--supervised

Run in the foreground, sending logs by default to stderr, and listening on provided file descriptors, which must already be bound to listening sockets. This command is useful when running under systemd or other similar process supervision schemes. This option is not supported on Windows.

In –supervised mode, different file descriptors can be provided for use as different socket types (e.g. ssh, extra) as long as they are identified in the environment variable LISTEN_FDNAMES (see sd_listen_fds(3) on some Linux distributions for more information on this convention).


2.2 Option Summary

Options may either be used on the command line or, after stripping off the two leading dashes, in the configuration file.

--options file

Reads configuration from file instead of from the default per-user configuration file. The default configuration file is named gpg-agent.conf and expected in the .gnupg directory directly below the home directory of the user. This option is ignored if used in an options file.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

-v
--verbose

Outputs additional information while running. You can increase the verbosity by giving several verbose commands to gpg-agent, such as ‘-vv’.

-q
--quiet

Try to be as quiet as possible.

--batch

Don’t invoke a pinentry or do any other thing requiring human interaction.

--faked-system-time epoch

This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsed since the year 1970.

--debug-level level

Select the debug level for investigating problems. level may be a numeric value or a keyword:

none

No debugging at all. A value of less than 1 may be used instead of the keyword.

basic

Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.

advanced

More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.

expert

Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.

guru

All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

--debug flags

Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice.

--debug-all

Same as --debug=0xffffffff

--debug-wait n

When running in server mode, wait n seconds before entering the actual processing loop and print the pid. This gives time to attach a debugger.

--debug-quick-random

This option inhibits the use of the very secure random quality level (Libgcrypt’s GCRY_VERY_STRONG_RANDOM) and degrades all request down to standard random quality. It is only used for testing and should not be used for any production quality keys. This option is only effective when given on the command line.

On GNU/Linux, another way to quickly generate insecure keys is to use rngd to fill the kernel’s entropy pool with lower quality random data. rngd is typically provided by the rng-tools package. It can be run as follows: ‘sudo rngd -f -r /dev/urandom’.

--debug-pinentry

This option enables extra debug information pertaining to the Pinentry. As of now it is only useful when used along with --debug 1024.

--no-detach

Don’t detach the process from the console. This is mainly useful for debugging.

--steal-socket

In --daemon mode, gpg-agent detects an already running gpg-agent and does not allow to start a new instance. This option can be used to override this check: the new gpg-agent process will try to take over the communication sockets from the already running process and start anyway. This option should in general not be used.

-s
--sh
-c
--csh

Format the info output in daemon mode for use with the standard Bourne shell or the C-shell respectively. The default is to guess it based on the environment variable SHELL which is correct in almost all cases.

--grab
--no-grab

Tell the pinentry to grab the keyboard and mouse. This option should be used on X-Servers to avoid X-sniffing attacks. Any use of the option --grab overrides an used option --no-grab. The default is --no-grab.

--log-file file

Append all logging output to file. This is very helpful in seeing what the agent actually does. Use socket:// to log to socket. If neither a log file nor a log file descriptor has been set on a Windows platform, the Registry entry HKCU\Software\GNU\GnuPG:DefaultLogFile, if set, is used to specify the logging output.

--no-allow-mark-trusted

Do not allow clients to mark keys as trusted, i.e. put them into the trustlist.txt file. This makes it harder for users to inadvertently accept Root-CA keys.

--allow-preset-passphrase

This option allows the use of gpg-preset-passphrase to seed the internal cache of gpg-agent with passphrases.

--no-allow-loopback-pinentry
--allow-loopback-pinentry

Disallow or allow clients to use the loopback pinentry features; see the option pinentry-mode for details. Allow is the default.

The --force option of the Assuan command DELETE_KEY is also controlled by this option: The option is ignored if a loopback pinentry is disallowed.

--no-allow-external-cache

Tell Pinentry not to enable features which use an external cache for passphrases.

Some desktop environments prefer to unlock all credentials with one master password and may have installed a Pinentry which employs an additional external cache to implement such a policy. By using this option the Pinentry is advised not to make use of such a cache and instead always ask the user for the requested passphrase.

--allow-emacs-pinentry

Tell Pinentry to allow features to divert the passphrase entry to a running Emacs instance. How this is exactly handled depends on the version of the used Pinentry.

--ignore-cache-for-signing

This option will let gpg-agent bypass the passphrase cache for all signing operation. Note that there is also a per-session option to control this behavior but this command line option takes precedence.

--default-cache-ttl n

Set the time a cache entry is valid to n seconds. The default is 600 seconds. Each time a cache entry is accessed, the entry’s timer is reset. To set an entry’s maximum lifetime, use max-cache-ttl. Note that a cached passphrase may not be evicted immediately from memory if no client requests a cache operation. This is due to an internal housekeeping function which is only run every few seconds.

--default-cache-ttl-ssh n

Set the time a cache entry used for SSH keys is valid to n seconds. The default is 1800 seconds. Each time a cache entry is accessed, the entry’s timer is reset. To set an entry’s maximum lifetime, use max-cache-ttl-ssh.

--max-cache-ttl n

Set the maximum time a cache entry is valid to n seconds. After this time a cache entry will be expired even if it has been accessed recently or has been set using gpg-preset-passphrase. The default is 2 hours (7200 seconds).

--max-cache-ttl-ssh n

Set the maximum time a cache entry used for SSH keys is valid to n seconds. After this time a cache entry will be expired even if it has been accessed recently or has been set using gpg-preset-passphrase. The default is 2 hours (7200 seconds).

--enforce-passphrase-constraints

Enforce the passphrase constraints by not allowing the user to bypass them using the “Take it anyway” button.

--min-passphrase-len n

Set the minimal length of a passphrase. When entering a new passphrase shorter than this value a warning will be displayed. Defaults to 8.

--min-passphrase-nonalpha n

Set the minimal number of digits or special characters required in a passphrase. When entering a new passphrase with less than this number of digits or special characters a warning will be displayed. Defaults to 1.

--check-passphrase-pattern file
--check-sym-passphrase-pattern file

Check the passphrase against the pattern given in file. When entering a new passphrase matching one of these pattern a warning will be displayed. If file does not contain any slashes and does not start with "~/" it is searched in the system configuration directory (/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/gnupg). The default is not to use any pattern file. The second version of this option is only used when creating a new symmetric key to allow the use of different patterns for such passphrases.

Security note: It is known that checking a passphrase against a list of pattern or even against a complete dictionary is not very effective to enforce good passphrases. Users will soon figure up ways to bypass such a policy. A better policy is to educate users on good security behavior and optionally to run a passphrase cracker regularly on all users passphrases to catch the very simple ones.

--max-passphrase-days n

Ask the user to change the passphrase if n days have passed since the last change. With --enforce-passphrase-constraints set the user may not bypass this check.

--enable-passphrase-history

This option does nothing yet.

--pinentry-invisible-char char

This option asks the Pinentry to use char for displaying hidden characters. char must be one character UTF-8 string. A Pinentry may or may not honor this request.

--pinentry-timeout n

This option asks the Pinentry to timeout after n seconds with no user input. The default value of 0 does not ask the pinentry to timeout, however a Pinentry may use its own default timeout value in this case. A Pinentry may or may not honor this request.

--pinentry-formatted-passphrase

This option asks the Pinentry to enable passphrase formatting when asking the user for a new passphrase and masking of the passphrase is turned off.

If passphrase formatting is enabled, then all non-breaking space characters are stripped from the entered passphrase. Passphrase formatting is mostly useful in combination with passphrases generated with the GENPIN feature of some Pinentries. Note that such a generated passphrase, if not modified by the user, skips all passphrase constraints checking because such constraints would actually weaken the generated passphrase.

--pinentry-program filename

Use program filename as the PIN entry. The default is installation dependent. With the default configuration the name of the default pinentry is pinentry; if that file does not exist but a pinentry-basic exist the latter is used.

On a Windows platform the default is to use the first existing program from this list: bin\pinentry.exe, ..\Gpg4win\bin\pinentry.exe, ..\Gpg4win\pinentry.exe, ..\GNU\GnuPG\pinentry.exe, ..\GNU\bin\pinentry.exe, bin\pinentry-basic.exe where the file names are relative to the GnuPG installation directory.

--pinentry-touch-file filename

By default the filename of the socket gpg-agent is listening for requests is passed to Pinentry, so that it can touch that file before exiting (it does this only in curses mode). This option changes the file passed to Pinentry to filename. The special name /dev/null may be used to completely disable this feature. Note that Pinentry will not create that file, it will only change the modification and access time.

--scdaemon-program filename

Use program filename as the Smartcard daemon. The default is installation dependent and can be shown with the gpgconf command.

--disable-scdaemon

Do not make use of the scdaemon tool. This option has the effect of disabling the ability to do smartcard operations. Note, that enabling this option at runtime does not kill an already forked scdaemon.

--disable-check-own-socket

gpg-agent employs a periodic self-test to detect a stolen socket. This usually means a second instance of gpg-agent has taken over the socket and gpg-agent will then terminate itself. This option may be used to disable this self-test for debugging purposes.

--use-standard-socket
--no-use-standard-socket
--use-standard-socket-p

Since GnuPG 2.1 the standard socket is always used. These options have no more effect. The command gpg-agent --use-standard-socket-p will thus always return success.

--display string
--ttyname string
--ttytype string
--lc-ctype string
--lc-messages string
--xauthority string

These options are used with the server mode to pass localization information.

--keep-tty
--keep-display

Ignore requests to change the current tty or X window system’s DISPLAY variable respectively. This is useful to lock the pinentry to pop up at the tty or display you started the agent.

--listen-backlog n

Set the size of the queue for pending connections. The default is 64.

--extra-socket name

The extra socket is created by default, you may use this option to change the name of the socket. To disable the creation of the socket use “none” or “/dev/null” for name.

Also listen on native gpg-agent connections on the given socket. The intended use for this extra socket is to setup a Unix domain socket forwarding from a remote machine to this socket on the local machine. A gpg running on the remote machine may then connect to the local gpg-agent and use its private keys. This enables decrypting or signing data on a remote machine without exposing the private keys to the remote machine.

--enable-extended-key-format
--disable-extended-key-format

Since version 2.3 keys are created in the extended private key format. Changing the passphrase of a key will also convert the key to that new format. This new key format is supported since GnuPG version 2.1.12 and thus there should be no need to disable it. The disable option allows to revert to the old behavior for new keys; be aware that keys are never migrated back to the old format. However if the enable option has been used the disable option won’t have an effect. The advantage of the extended private key format is that it is text based and can carry additional meta data.

--enable-ssh-support
--enable-putty-support

The OpenSSH Agent protocol is always enabled, but gpg-agent will only set the SSH_AUTH_SOCK variable if this flag is given.

In this mode of operation, the agent does not only implement the gpg-agent protocol, but also the agent protocol used by OpenSSH (through a separate socket). Consequently, it should be possible to use the gpg-agent as a drop-in replacement for the well known ssh-agent.

SSH Keys, which are to be used through the agent, need to be added to the gpg-agent initially through the ssh-add utility. When a key is added, ssh-add will ask for the password of the provided key file and send the unprotected key material to the agent; this causes the gpg-agent to ask for a passphrase, which is to be used for encrypting the newly received key and storing it in a gpg-agent specific directory.

Once a key has been added to the gpg-agent this way, the gpg-agent will be ready to use the key.

Note: in case the gpg-agent receives a signature request, the user might need to be prompted for a passphrase, which is necessary for decrypting the stored key. Since the ssh-agent protocol does not contain a mechanism for telling the agent on which display/terminal it is running, gpg-agent’s ssh-support will use the TTY or X display where gpg-agent has been started. To switch this display to the current one, the following command may be used:

gpg-connect-agent updatestartuptty /bye

Although all GnuPG components try to start the gpg-agent as needed, this is not possible for the ssh support because ssh does not know about it. Thus if no GnuPG tool which accesses the agent has been run, there is no guarantee that ssh is able to use gpg-agent for authentication. To fix this you may start gpg-agent if needed using this simple command:

gpg-connect-agent /bye

Adding the --verbose shows the progress of starting the agent.

The --enable-putty-support is only available under Windows and allows the use of gpg-agent with the ssh implementation putty. This is similar to the regular ssh-agent support but makes use of Windows message queue as required by putty.

--ssh-fingerprint-digest

Select the digest algorithm used to compute ssh fingerprints that are communicated to the user, e.g. in pinentry dialogs. OpenSSH has transitioned from using MD5 to the more secure SHA256.

--auto-expand-secmem n

Allow Libgcrypt to expand its secure memory area as required. The optional value n is a non-negative integer with a suggested size in bytes of each additionally allocated secure memory area. The value is rounded up to the next 32 KiB; usual C style prefixes are allowed. For an heavy loaded gpg-agent with many concurrent connection this option avoids sign or decrypt errors due to out of secure memory error returns.

--s2k-calibration milliseconds

Change the default calibration time to milliseconds. The given value is capped at 60 seconds; a value of 0 resets to the compiled-in default. This option is re-read on a SIGHUP (or gpgconf --reload gpg-agent) and the S2K count is then re-calibrated.

--s2k-count n

Specify the iteration count used to protect the passphrase. This option can be used to override the auto-calibration done by default. The auto-calibration computes a count which requires by default 100ms to mangle a given passphrase. See also --s2k-calibration.

To view the actually used iteration count and the milliseconds required for an S2K operation use:

gpg-connect-agent 'GETINFO s2k_count' /bye
gpg-connect-agent 'GETINFO s2k_time' /bye

To view the auto-calibrated count use:

gpg-connect-agent 'GETINFO s2k_count_cal' /bye

2.3 Configuration

There are a few configuration files needed for the operation of the agent. By default they may all be found in the current home directory (see option --homedir).

gpg-agent.conf

This is the standard configuration file read by gpg-agent on startup. It may contain any valid long option; the leading two dashes may not be entered and the option may not be abbreviated. This file is also read after a SIGHUP however only a few options will actually have an effect. This default name may be changed on the command line (see option --options). You should backup this file.

trustlist.txt

This is the list of trusted keys. You should backup this file.

Comment lines, indicated by a leading hash mark, as well as empty lines are ignored. To mark a key as trusted you need to enter its fingerprint followed by a space and a capital letter S. Colons may optionally be used to separate the bytes of a fingerprint; this enables cutting and pasting the fingerprint from a key listing output. If the line is prefixed with a ! the key is explicitly marked as not trusted.

Here is an example where two keys are marked as ultimately trusted and one as not trusted:

  # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
  A6935DD34EF3087973C706FC311AA2CCF733765B S

  # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
  DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S

  # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
  !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
  

Before entering a key into this file, you need to ensure its authenticity. How to do this depends on your organisation; your administrator might have already entered those keys which are deemed trustworthy enough into this file. Places where to look for the fingerprint of a root certificate are letters received from the CA or the website of the CA (after making 100% sure that this is indeed the website of that CA). You may want to consider disallowing interactive updates of this file by using the option --no-allow-mark-trusted. It might even be advisable to change the permissions to read-only so that this file can’t be changed inadvertently.

As a special feature a line include-default will include a global list of trusted certificates (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/gnupg/trustlist.txt). This global list is also used if the local list is not available.

It is possible to add further flags after the S for use by the caller:

relax

Relax checking of some root certificate requirements. As of now this flag allows the use of root certificates with a missing basicConstraints attribute (despite that it is a MUST for CA certificates) and disables CRL checking for the root certificate.

cm

If validation of a certificate finally issued by a CA with this flag set fails, try again using the chain validation model.

sshcontrol

This file is used when support for the secure shell agent protocol has been enabled (see option --enable-ssh-support). Only keys present in this file are used in the SSH protocol. You should backup this file.

The ssh-add tool may be used to add new entries to this file; you may also add them manually. Comment lines, indicated by a leading hash mark, as well as empty lines are ignored. An entry starts with optional whitespace, followed by the keygrip of the key given as 40 hex digits, optionally followed by the caching TTL in seconds and another optional field for arbitrary flags. A non-zero TTL overrides the global default as set by --default-cache-ttl-ssh.

The only flag support is confirm. If this flag is found for a key, each use of the key will pop up a pinentry to confirm the use of that key. The flag is automatically set if a new key was loaded into gpg-agent using the option -c of the ssh-add command.

The keygrip may be prefixed with a ! to disable an entry.

The following example lists exactly one key. Note that keys available through a OpenPGP smartcard in the active smartcard reader are implicitly added to this list; i.e. there is no need to list them.

       # Key added on: 2011-07-20 20:38:46
       # Fingerprint:  5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
       34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
private-keys-v1.d/

This is the directory where gpg-agent stores the private keys. Each key is stored in a file with the name made up of the keygrip and the suffix key. You should backup all files in this directory and take great care to keep this backup closed away.

Note that on larger installations, it is useful to put predefined files into the directory /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/skel/.gnupg so that newly created users start up with a working configuration. For existing users the a small helper script is provided to create these files (see Create .gnupg home directories).


2.4 Use of some signals

A running gpg-agent may be controlled by signals, i.e. using the kill command to send a signal to the process.

Here is a list of supported signals:

SIGHUP

This signal flushes all cached passphrases and if the program has been started with a configuration file, the configuration file is read again. Only certain options are honored: quiet, verbose, debug, debug-all, debug-level, debug-pinentry, no-grab, pinentry-program, pinentry-invisible-char, default-cache-ttl, max-cache-ttl, ignore-cache-for-signing, s2k-count, no-allow-external-cache, allow-emacs-pinentry, no-allow-mark-trusted, disable-scdaemon, and disable-check-own-socket. scdaemon-program is also supported but due to the current implementation, which calls the scdaemon only once, it is not of much use unless you manually kill the scdaemon.

SIGTERM

Shuts down the process but waits until all current requests are fulfilled. If the process has received 3 of these signals and requests are still pending, a shutdown is forced.

SIGINT

Shuts down the process immediately.

SIGUSR1

Dump internal information to the log file.

SIGUSR2

This signal is used for internal purposes.


2.5 Examples

It is important to set the environment variable GPG_TTY in your login shell, for example in the ~/.bashrc init script:

  export GPG_TTY=$(tty)

If you enabled the Ssh Agent Support, you also need to tell ssh about it by adding this to your init script:

unset SSH_AGENT_PID
if [ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]; then
  export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
fi

Previous: , Up: Invoking GPG-AGENT   [Contents][Index]

2.6 Agent’s Assuan Protocol

Note: this section does only document the protocol, which is used by GnuPG components; it does not deal with the ssh-agent protocol. To see the full specification of each command, use

  gpg-connect-agent 'help COMMAND' /bye

or just ’help’ to list all available commands.

The gpg-agent daemon is started on demand by the GnuPG components.

To identify a key we use a thing called keygrip which is the SHA-1 hash of an canonical encoded S-Expression of the public key as used in Libgcrypt. For the purpose of this interface the keygrip is given as a hex string. The advantage of using this and not the hash of a certificate is that it will be possible to use the same keypair for different protocols, thereby saving space on the token used to keep the secret keys.

The gpg-agent may send status messages during a command or when returning from a command to inform a client about the progress or result of an operation. For example, the INQUIRE_MAXLEN status message may be sent during a server inquire to inform the client of the maximum usable length of the inquired data (which should not be exceeded).


2.6.1 Decrypting a session key

The client asks the server to decrypt a session key. The encrypted session key should have all information needed to select the appropriate secret key or to delegate it to a smartcard.

  SETKEY <keyGrip>

Tell the server about the key to be used for decryption. If this is not used, gpg-agent may try to figure out the key by trying to decrypt the message with each key available.

  PKDECRYPT

The agent checks whether this command is allowed and then does an INQUIRY to get the ciphertext the client should then send the cipher text.

    S: INQUIRE CIPHERTEXT
    C: D (xxxxxx
    C: D xxxx)
    C: END

Please note that the server may send status info lines while reading the data lines from the client. The data send is a SPKI like S-Exp with this structure:

     (enc-val
       (<algo>
         (<param_name1> <mpi>)
 	   ...
         (<param_namen> <mpi>)))

Where algo is a string with the name of the algorithm; see the libgcrypt documentation for a list of valid algorithms. The number and names of the parameters depend on the algorithm. The agent does return an error if there is an inconsistency.

If the decryption was successful the decrypted data is returned by means of "D" lines.

Here is an example session:

   C: PKDECRYPT
   S: INQUIRE CIPHERTEXT
   C: D (enc-val elg (a 349324324)
   C: D    (b 3F444677CA)))
   C: END
   S: # session key follows
   S: S PADDING 0
   S: D (value 1234567890ABCDEF0)
   S: OK decryption successful

The “PADDING” status line is only send if gpg-agent can tell what kind of padding is used. As of now only the value 0 is used to indicate that the padding has been removed.


2.6.2 Signing a Hash

The client asks the agent to sign a given hash value. A default key will be chosen if no key has been set. To set a key a client first uses:

   SIGKEY <keyGrip>

This can be used multiple times to create multiple signature, the list of keys is reset with the next PKSIGN command or a RESET. The server tests whether the key is a valid key to sign something and responds with okay.

   SETHASH --hash=<name>|<algo> <hexstring>

The client can use this command to tell the server about the data <hexstring> (which usually is a hash) to be signed. <algo> is the decimal encoded hash algorithm number as used by Libgcrypt. Either <algo> or –hash=<name> must be given. Valid names for <name> are:

sha1

The SHA-1 hash algorithm

sha256

The SHA-256 hash algorithm

rmd160

The RIPE-MD160 hash algorithm

md5

The old and broken MD5 hash algorithm

tls-md5sha1

A combined hash algorithm as used by the TLS protocol.

The actual signing is done using

   PKSIGN <options>

Options are not yet defined, but may later be used to choose among different algorithms. The agent does then some checks, asks for the passphrase and as a result the server returns the signature as an SPKI like S-expression in "D" lines:

     (sig-val
       (<algo>
         (<param_name1> <mpi>)
 	   ...
         (<param_namen> <mpi>)))

The operation is affected by the option

   OPTION use-cache-for-signing=0|1

The default of 1 uses the cache. Setting this option to 0 will lead gpg-agent to ignore the passphrase cache. Note, that there is also a global command line option for gpg-agent to globally disable the caching.

Here is an example session:

   C: SIGKEY <keyGrip>
   S: OK key available
   C: SIGKEY <keyGrip>
   S: OK key available
   C: PKSIGN
   S: # I did ask the user whether he really wants to sign
   S: # I did ask the user for the passphrase
   S: INQUIRE HASHVAL
   C: D ABCDEF012345678901234
   C: END
   S: # signature follows
   S: D (sig-val rsa (s 45435453654612121212))
   S: OK

2.6.3 Generating a Key

This is used to create a new keypair and store the secret key inside the active PSE — which is in most cases a Soft-PSE. A not-yet-defined option allows choosing the storage location. To get the secret key out of the PSE, a special export tool has to be used.

   GENKEY [--no-protection] [--preset] [<cache_nonce>]

Invokes the key generation process and the server will then inquire on the generation parameters, like:

   S: INQUIRE KEYPARM
   C: D (genkey (rsa (nbits  1024)))
   C: END

The format of the key parameters which depends on the algorithm is of the form:

    (genkey
      (algo
        (parameter_name_1 ....)
          ....
        (parameter_name_n ....)))

If everything succeeds, the server returns the *public key* in a SPKI like S-Expression like this:

     (public-key
       (rsa
 	 (n <mpi>)
 	 (e <mpi>)))

Here is an example session:

   C: GENKEY
   S: INQUIRE KEYPARM
   C: D (genkey (rsa (nbits  1024)))
   C: END
   S: D (public-key
   S: D   (rsa (n 326487324683264) (e 10001)))
   S  OK key created

The --no-protection option may be used to prevent prompting for a passphrase to protect the secret key while leaving the secret key unprotected. The --preset option may be used to add the passphrase to the cache using the default cache parameters.

The --inq-passwd option may be used to create the key with a supplied passphrase. When used the agent does an inquiry with the keyword NEWPASSWD to retrieve that passphrase. This option takes precedence over --no-protection; however if the client sends a empty (zero-length) passphrase, this is identical to --no-protection.


2.6.4 Importing a Secret Key

This operation is not yet supported by GpgAgent. Specialized tools are to be used for this.

There is no actual need because we can expect that secret keys created by a 3rd party are stored on a smartcard. If we have generated the key ourselves, we do not need to import it.


2.6.5 Export a Secret Key

Not implemented.

Should be done by an extra tool.


2.6.6 Importing a Root Certificate

Actually we do not import a Root Cert but provide a way to validate any piece of data by storing its Hash along with a description and an identifier in the PSE. Here is the interface description:

    ISTRUSTED <fingerprint>

Check whether the OpenPGP primary key or the X.509 certificate with the given fingerprint is an ultimately trusted key or a trusted Root CA certificate. The fingerprint should be given as a hexstring (without any blanks or colons or whatever in between) and may be left padded with 00 in case of an MD5 fingerprint. GPGAgent will answer with:

    OK

The key is in the table of trusted keys.

    ERR 304 (Not Trusted)

The key is not in this table.

Gpg needs the entire list of trusted keys to maintain the web of trust; the following command is therefore quite helpful:

    LISTTRUSTED

GpgAgent returns a list of trusted keys line by line:

    S: D 000000001234454556565656677878AF2F1ECCFF P
    S: D 340387563485634856435645634856438576457A P
    S: D FEDC6532453745367FD83474357495743757435D S
    S: OK

The first item on a line is the hexified fingerprint where MD5 fingerprints are 00 padded to the left and the second item is a flag to indicate the type of key (so that gpg is able to only take care of PGP keys). P = OpenPGP, S = S/MIME. A client should ignore the rest of the line, so that we can extend the format in the future.

Finally a client should be able to mark a key as trusted:

   MARKTRUSTED fingerprint "P"|"S"

The server will then pop up a window to ask the user whether she really trusts this key. For this it will probably ask for a text to be displayed like this:

   S: INQUIRE TRUSTDESC
   C: D Do you trust the key with the fingerprint @FPR@
   C: D bla fasel blurb.
   C: END
   S: OK

Known sequences with the pattern @foo@ are replaced according to this table:

@FPR16@

Format the fingerprint according to gpg rules for a v3 keys.

@FPR20@

Format the fingerprint according to gpg rules for a v4 keys.

@FPR@

Choose an appropriate format to format the fingerprint.

@@

Replaced by a single @.


2.6.7 Ask for a passphrase

This function is usually used to ask for a passphrase to be used for symmetric encryption, but may also be used by programs which need special handling of passphrases. This command uses a syntax which helps clients to use the agent with minimum effort.

  GET_PASSPHRASE [--data] [--check] [--no-ask] [--repeat[=N]] \
                 [--qualitybar] cache_id                \
                 [error_message prompt description]

cache_id is expected to be a string used to identify a cached passphrase. Use a X to bypass the cache. With no other arguments the agent returns a cached passphrase or an error. By convention either the hexified fingerprint of the key shall be used for cache_id or an arbitrary string prefixed with the name of the calling application and a colon: Like gpg:somestring.

error_message is either a single X for no error message or a string to be shown as an error message like (e.g. "invalid passphrase"). Blanks must be percent escaped or replaced by +’.

prompt is either a single X for a default prompt or the text to be shown as the prompt. Blanks must be percent escaped or replaced by +.

description is a text shown above the entry field. Blanks must be percent escaped or replaced by +.

The agent either returns with an error or with a OK followed by the hex encoded passphrase. Note that the length of the strings is implicitly limited by the maximum length of a command. If the option --data is used, the passphrase is not returned on the OK line but by regular data lines; this is the preferred method.

If the option --check is used, the standard passphrase constraints checks are applied. A check is not done if the passphrase has been found in the cache.

If the option --no-ask is used and the passphrase is not in the cache the user will not be asked to enter a passphrase but the error code GPG_ERR_NO_DATA is returned.

If the option --qualitybar is used and a minimum passphrase length has been configured, a visual indication of the entered passphrase quality is shown.

  CLEAR_PASSPHRASE cache_id

may be used to invalidate the cache entry for a passphrase. The function returns with OK even when there is no cached passphrase.


2.6.8 Remove a cached passphrase

Use this command to remove a cached passphrase.

  CLEAR_PASSPHRASE [--mode=normal] <cache_id>

The --mode=normal option can be used to clear a cache_id that was set by gpg-agent.


2.6.9 Set a passphrase for a keygrip

This command adds a passphrase to the cache for the specified keygrip.

  PRESET_PASSPHRASE [--inquire] <string_or_keygrip> <timeout> [<hexstring>]

The passphrase is a hexadecimal string when specified. When not specified, the passphrase will be retrieved from the pinentry module unless the --inquire option was specified in which case the passphrase will be retrieved from the client.

The timeout parameter keeps the passphrase cached for the specified number of seconds. A value of -1 means infinite while 0 means the default (currently only a timeout of -1 is allowed, which means to never expire it).


2.6.10 Ask for confirmation

This command may be used to ask for a simple confirmation by presenting a text and 2 buttons: Okay and Cancel.

  GET_CONFIRMATION description

descriptionis displayed along with a Okay and Cancel button. Blanks must be percent escaped or replaced by +. A X may be used to display confirmation dialog with a default text.

The agent either returns with an error or with a OK. Note, that the length of description is implicitly limited by the maximum length of a command.


2.6.11 Check whether a key is available

This can be used to see whether a secret key is available. It does not return any information on whether the key is somehow protected.

  HAVEKEY keygrips

The agent answers either with OK or No_Secret_Key (208). The caller may want to check for other error codes as well. More than one keygrip may be given. In this case the command returns success if at least one of the keygrips corresponds to an available secret key.


2.6.12 Register a smartcard

  LEARN [--send]

This command is used to register a smartcard. With the --send option given the certificates are sent back.


2.6.13 Change a Passphrase

  PASSWD [--cache-nonce=<c>] [--passwd-nonce=<s>] [--preset] keygrip

This command is used to interactively change the passphrase of the key identified by the hex string keygrip. The --preset option may be used to add the new passphrase to the cache using the default cache parameters.


2.6.14 Change the standard display

  UPDATESTARTUPTTY

Set the startup TTY and X-DISPLAY variables to the values of this session. This command is useful to direct future pinentry invocations to another screen. It is only required because there is no way in the ssh-agent protocol to convey this information.


2.6.15 Get the Event Counters

  GETEVENTCOUNTER

This function return one status line with the current values of the event counters. The event counters are useful to avoid polling by delaying a poll until something has changed. The values are decimal numbers in the range 0 to UINT_MAX and wrapping around to 0. The actual values should not be relied upon; they shall only be used to detect a change.

The currently defined counters are:

ANY

Incremented with any change of any of the other counters.

KEY

Incremented for added or removed private keys.

CARD

Incremented for each change of the card reader’s status.


2.6.16 Return information about the process

This is a multipurpose function to return a variety of information.

GETINFO what

The value of what specifies the kind of information returned:

version

Return the version of the program.

pid

Return the process id of the process.

socket_name

Return the name of the socket used to connect the agent.

ssh_socket_name

Return the name of the socket used for SSH connections. If SSH support has not been enabled the error GPG_ERR_NO_DATA will be returned.


2.6.17 Set options for the session

Here is a list of session options which are not yet described with other commands. The general syntax for an Assuan option is:

OPTION  key=value

Supported keys are:

agent-awareness

This may be used to tell gpg-agent of which gpg-agent version the client is aware of. gpg-agent uses this information to enable features which might break older clients.

putenv

Change the session’s environment to be used for the Pinentry. Valid values are:

name

Delete envvar name

name=

Set envvar name to the empty string

name=value

Set envvar name to the string value.

use-cache-for-signing

See Assuan command PKSIGN.

allow-pinentry-notify

This does not need any value. It is used to enable the PINENTRY_LAUNCHED inquiry.

pinentry-mode

This option is used to change the operation mode of the pinentry. The following values are defined:

ask

This is the default mode which pops up a pinentry as needed.

cancel

Instead of popping up a pinentry, return the error code GPG_ERR_CANCELED.

error

Instead of popping up a pinentry, return the error code GPG_ERR_NO_PIN_ENTRY.

loopback

Use a loopback pinentry. This fakes a pinentry by using inquiries back to the caller to ask for a passphrase. This option may only be set if the agent has been configured for that. To disable this feature use option --no-allow-loopback-pinentry.

cache-ttl-opt-preset

This option sets the cache TTL for new entries created by GENKEY and PASSWD commands when using the --preset option. It is not used a default value is used.

s2k-count

Instead of using the standard S2K count (which is computed on the fly), the given S2K count is used for new keys or when changing the passphrase of a key. Values below 65536 are considered to be 0. This option is valid for the entire session or until reset to 0. This option is useful if the key is later used on boxes which are either much slower or faster than the actual box.

pretend-request-origin

This option switches the connection into a restricted mode which handles all further commands in the same way as they would be handled when originating from the extra or browser socket. Note that this option is not available in the restricted mode. Valid values for this option are:

none
local

This is a NOP and leaves the connection in the standard way.

remote

Pretend to come from a remote origin in the same way as connections from the --extra-socket.

browser

Pretend to come from a local web browser in the same way as connections from the --browser-socket.


3 Invoking DIRMNGR

Since version 2.1 of GnuPG, dirmngr takes care of accessing the OpenPGP keyservers. As with previous versions it is also used as a server for managing and downloading certificate revocation lists (CRLs) for X.509 certificates, downloading X.509 certificates, and providing access to OCSP providers. Dirmngr is invoked internally by gpg, gpgsm, or via the gpg-connect-agent tool.

See Option Index,for an index to DIRMNGR’s commands and options.


3.1 Commands

Commands are not distinguished from options except for the fact that only one command is allowed.

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help, -h

Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command.

--dump-options

Print a list of all available options and commands. Note that you cannot abbreviate this command.

--server

Run in server mode and wait for commands on the stdin. The default mode is to create a socket and listen for commands there. This is only used for testing.

--daemon

Run in background daemon mode and listen for commands on a socket. This is the way dirmngr is started on demand by the other GnuPG components. To force starting dirmngr it is in general best to use gpgconf --launch dirmngr.

--supervised

Run in the foreground, sending logs to stderr, and listening on file descriptor 3, which must already be bound to a listening socket. This is useful when running under systemd or other similar process supervision schemes. This option is not supported on Windows.

--list-crls

List the contents of the CRL cache on stdout. This is probably only useful for debugging purposes.

--load-crl file

This command requires a filename as additional argument, and it will make Dirmngr try to import the CRL in file into it’s cache. Note, that this is only possible if Dirmngr is able to retrieve the CA’s certificate directly by its own means. In general it is better to use gpgsm’s --call-dirmngr loadcrl filename command so that gpgsm can help dirmngr.

--fetch-crl url

This command requires an URL as additional argument, and it will make dirmngr try to retrieve and import the CRL from that url into it’s cache. This is mainly useful for debugging purposes. The dirmngr-client provides the same feature for a running dirmngr.

--shutdown

This commands shuts down an running instance of Dirmngr. This command has currently no effect.

--flush

This command removes all CRLs from Dirmngr’s cache. Client requests will thus trigger reading of fresh CRLs.


Next: , Previous: , Up: Invoking DIRMNGR   [Contents][Index]

3.2 Option Summary

Note that all long options with the exception of --options and --homedir may also be given in the configuration file after stripping off the two leading dashes.

--options file

Reads configuration from file instead of from the default per-user configuration file. The default configuration file is named dirmngr.conf and expected in the home directory.

--homedir dir

Set the name of the home directory to dir. This option is only effective when used on the command line. The default is the directory named .gnupg directly below the home directory of the user unless the environment variable GNUPGHOME has been set in which case its value will be used. Many kinds of data are stored within this directory.

-v
--verbose

Outputs additional information while running. You can increase the verbosity by giving several verbose commands to DIRMNGR, such as -vv.

--log-file file

Append all logging output to file. This is very helpful in seeing what the agent actually does. Use socket:// to log to socket.

--debug-level level

Select the debug level for investigating problems. level may be a numeric value or by a keyword:

none

No debugging at all. A value of less than 1 may be used instead of the keyword.

basic

Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.

advanced

More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.

expert

Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.

guru

All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

--debug flags

Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice.

--debug-all

Same as --debug=0xffffffff

--tls-debug level

Enable debugging of the TLS layer at level. The details of the debug level depend on the used TLS library and are not set in stone.

--debug-wait n

When running in server mode, wait n seconds before entering the actual processing loop and print the pid. This gives time to attach a debugger.

--disable-check-own-socket

On some platforms dirmngr is able to detect the removal of its socket file and shutdown itself. This option disable this self-test for debugging purposes.

-s
--sh
-c
--csh

Format the info output in daemon mode for use with the standard Bourne shell respective the C-shell. The default is to guess it based on the environment variable SHELL which is in almost all cases sufficient.

--force

Enabling this option forces loading of expired CRLs; this is only useful for debugging.

--use-tor
--no-use-tor

The option --use-tor switches Dirmngr and thus GnuPG into “Tor mode” to route all network access via Tor (an anonymity network). Certain other features are disabled in this mode. The effect of --use-tor cannot be overridden by any other command or even by reloading dirmngr. The use of --no-use-tor disables the use of Tor. The default is to use Tor if it is available on startup or after reloading dirmngr. The test on the availability of Tor is done by trying to connect to a SOCKS proxy at either port 9050 or 9150; if another type of proxy is listening on one of these ports, you should use --no-use-tor.

--standard-resolver

This option forces the use of the system’s standard DNS resolver code. This is mainly used for debugging. Note that on Windows a standard resolver is not used and all DNS access will return the error “Not Implemented” if this option is used. Using this together with enabled Tor mode returns the error “Not Enabled”.

--recursive-resolver

When possible use a recursive resolver instead of a stub resolver.

--resolver-timeout n

Set the timeout for the DNS resolver to N seconds. The default are 30 seconds.

--connect-timeout n
--connect-quick-timeout n

Set the timeout for HTTP and generic TCP connection attempts to N seconds. The value set with the quick variant is used when the –quick option has been given to certain Assuan commands. The quick value is capped at the value of the regular connect timeout. The default values are 15 and 2 seconds. Note that the timeout values are for each connection attempt; the connection code will attempt to connect all addresses listed for a server.

--listen-backlog n

Set the size of the queue for pending connections. The default is 64.

--allow-version-check

Allow Dirmngr to connect to https://versions.gnupg.org to get the list of current software versions. If this option is enabled the list is retrieved in case the local copy does not exist or is older than 5 to 7 days. See the option --query-swdb of the command gpgconf for more details. Note, that regardless of this option a version check can always be triggered using this command:

       gpg-connect-agent --dirmngr 'loadswdb --force' /bye
--keyserver name

Use name as your keyserver. This is the server that gpg communicates with to receive keys, send keys, and search for keys. The format of the name is a URI: ‘scheme:[//]keyservername[:port]’ The scheme is the type of keyserver: "hkp" for the HTTP (or compatible) keyservers, "ldap" for the LDAP keyservers, or "mailto" for the Graff email keyserver. Note that your particular installation of GnuPG may have other keyserver types available as well. Keyserver schemes are case-insensitive. After the keyserver name, optional keyserver configuration options may be provided. These are the same as the --keyserver-options of gpg, but apply only to this particular keyserver.

Most keyservers synchronize with each other, so there is generally no need to send keys to more than one server. Somes keyservers use round robin DNS to give a different keyserver each time you use it.

If exactly two keyservers are configured and only one is a Tor hidden service (.onion), Dirmngr selects the keyserver to use depending on whether Tor is locally running or not. The check for a running Tor is done for each new connection.

If no keyserver is explicitly configured, dirmngr will use the built-in default of hkps://keys.openpgp.org.

Windows users with a keyserver running on their Active Directory may use the short form ldap:/// for name to access this directory.

For accessing anonymous LDAP keyservers name is in general just a ldaps://ldap.example.com. A BaseDN parameter should never be specified. If authentication is required things are more complicated and two methods are available:

The modern method (since version 2.2.28) is to use the very same syntax as used with the option --ldapserver. Please see over there for details; here is an example:

       keyserver ldap:ldap.example.com::uid=USERNAME,ou=GnuPG Users,
       dc=example,dc=com:PASSWORD::starttls

The other method is to use a full URL for name; for example:

       keyserver ldaps://ldap.example.com/????bindname=uid=USERNAME
       %2Cou=GnuPG%20Users%2Cdc=example%2Cdc=com,password=PASSWORD

Put this all on one line without any spaces and keep the ’%2C’ as given. Replace USERNAME, PASSWORD, and the ’dc’ parts according to the instructions received from your LDAP administrator. Note that only simple authentication (i.e. cleartext passwords) is supported and thus using ldaps is strongly suggested (since 2.2.28 "ldaps" defaults to port 389 and uses STARTTLS). On Windows authentication via AD can be requested by adding gpgNtds=1 after the fourth question mark instead of the bindname and password parameter.

--nameserver ipaddr

In “Tor mode” Dirmngr uses a public resolver via Tor to resolve DNS names. If the default public resolver, which is 8.8.8.8, shall not be used a different one can be given using this option. Note that a numerical IP address must be given (IPv6 or IPv4) and that no error checking is done for ipaddr.

--disable-ipv4
--disable-ipv6

Disable the use of all IPv4 or IPv6 addresses.

--disable-ldap

Entirely disables the use of LDAP.

--disable-http

Entirely disables the use of HTTP.

--ignore-http-dp

When looking for the location of a CRL, the to be tested certificate usually contains so called CRL Distribution Point (DP) entries which are URLs describing the way to access the CRL. The first found DP entry is used. With this option all entries using the HTTP scheme are ignored when looking for a suitable DP.

--ignore-ldap-dp

This is similar to --ignore-http-dp but ignores entries using the LDAP scheme. Both options may be combined resulting in ignoring DPs entirely.

--ignore-ocsp-service-url

Ignore all OCSP URLs contained in the certificate. The effect is to force the use of the default responder.

--honor-http-proxy

If the environment variable http_proxy has been set, use its value to access HTTP servers.

--http-proxy host[:port]

Use host and port to access HTTP servers. The use of this option overrides the environment variable http_proxy regardless whether --honor-http-proxy has been set.

--ldap-proxy host[:port]

Use host and port to connect to LDAP servers. If port is omitted, port 389 (standard LDAP port) is used. This overrides any specified host and port part in a LDAP URL and will also be used if host and port have been omitted from the URL.

--only-ldap-proxy

Never use anything else but the LDAP "proxy" as configured with --ldap-proxy. Usually dirmngr tries to use other configured LDAP server if the connection using the "proxy" failed.

--ldapserverlist-file file

Read the list of LDAP servers to consult for CRLs and X.509 certificates from file instead of the default per-user ldap server list file. The default value for file is dirmngr_ldapservers.conf.

This server list file contains one LDAP server per line in the format

HOSTNAME:PORT:USERNAME:PASSWORD:BASE_DN:FLAGS

Lines starting with a ‘#’ are comments.

Note that as usual all strings entered are expected to be UTF-8 encoded. Obviously this will lead to problems if the password has originally been encoded as Latin-1. There is no other solution here than to put such a password in the binary encoding into the file (i.e. non-ascii characters won’t show up readable).1

--ldapserver spec

This is an alternative way to specify LDAP servers for CRL and X.509 certificate retrieval. If this option is used the servers configured in dirmngr_ldapservers.conf (or the file given by --ldapserverlist-file) are cleared. Note that dirmngr_ldapservers.conf is not read again by a reload signal. However, --ldapserver options are read again.

spec is either a proper LDAP URL or a colon delimited list of the form

HOSTNAME:PORT:USERNAME:PASSWORD:BASE_DN:FLAGS:

with an optional prefix of ldap: (but without the two slashes which would turn this into a proper LDAP URL). FLAGS is a list of one or more comma delimited keywords:

plain

The default: Do not use a TLS secured connection at all; the default port is 389.

starttls

Use STARTTLS to secure the connection; the default port is 389.

ldaptls

Tunnel LDAP through a TLS connection; the default port is 636.

ntds

On Windows authenticate the LDAP connection using the Active Directory with the current user.

Note that in an URL style specification the scheme ldaps:// refers to STARTTLS and _not_ to LDAP-over-TLS.

--ldaptimeout secs

Specify the number of seconds to wait for an LDAP query before timing out. The default are 15 seconds. 0 will never timeout.

--add-servers

This option makes dirmngr add any servers it discovers when validating certificates against CRLs to the internal list of servers to consult for certificates and CRLs. This option should in general not be used.

This option might be useful when trying to validate a certificate that has a CRL distribution point that points to a server that is not already listed in the ldapserverlist. Dirmngr will always go to this server and try to download the CRL, but chances are high that the certificate used to sign the CRL is located on the same server. So if dirmngr doesn’t add that new server to list, it will often not be able to verify the signature of the CRL unless the --add-servers option is used.

Caveat emptor: Using this option may enable denial-of-service attacks and leak search requests to unknown third parties. This is because arbitrary servers are added to the internal list of LDAP servers which in turn is used for all unspecific LDAP queries as well as a fallback for queries which did not return a result.

--allow-ocsp

This option enables OCSP support if requested by the client.

OCSP requests are rejected by default because they may violate the privacy of the user; for example it is possible to track the time when a user is reading a mail.

--ocsp-responder url

Use url as the default OCSP Responder if the certificate does not contain information about an assigned responder. Note, that --ocsp-signer must also be set to a valid certificate.

--ocsp-signer fpr|file

Use the certificate with the fingerprint fpr to check the responses of the default OCSP Responder. Alternatively a filename can be given in which case the response is expected to be signed by one of the certificates described in that file. Any argument which contains a slash, dot or tilde is considered a filename. Usual filename expansion takes place: A tilde at the start followed by a slash is replaced by the content of HOME, no slash at start describes a relative filename which will be searched at the home directory. To make sure that the file is searched in the home directory, either prepend the name with "./" or use a name which contains a dot.

If a response has been signed by a certificate described by these fingerprints no further check upon the validity of this certificate is done.

The format of the FILE is a list of SHA-1 fingerprint, one per line with optional colons between the bytes. Empty lines and lines prefix with a hash mark are ignored.

--ocsp-max-clock-skew n

The number of seconds a skew between the OCSP responder and them local clock is accepted. Default is 600 (10 minutes).

--ocsp-max-period n

Seconds a response is at maximum considered valid after the time given in the thisUpdate field. Default is 7776000 (90 days).

--ocsp-current-period n

The number of seconds an OCSP response is considered valid after the time given in the NEXT_UPDATE datum. Default is 10800 (3 hours).

--max-replies n

Do not return more that n items in one query. The default is 10.

--ignore-cert-extension oid

Add oid to the list of ignored certificate extensions. The oid is expected to be in dotted decimal form, like 2.5.29.3. This option may be used more than once. Critical flagged certificate extensions matching one of the OIDs in the list are treated as if they are actually handled and thus the certificate won’t be rejected due to an unknown critical extension. Use this option with care because extensions are usually flagged as critical for a reason.

--ignore-cert fpr|file

Entirely ignore certificates with the fingerprint fpr. As an alternative to the fingerprint a filename can be given in which case all certificates described in that file are ignored. Any argument which contains a slash, dot or tilde is considered a filename. Usual filename expansion takes place: A tilde at the start followed by a slash is replaced by the content of HOME, no slash at start describes a relative filename which will be searched at the home directory. To make sure that the file is searched in the home directory, either prepend the name with "./" or use a name which contains a dot. The format of such a file is a list of SHA-1 fingerprint, one per line with optional colons between the bytes. Empty lines and lines prefixed with a hash mark are ignored.

This option is useful as a quick workaround to exclude certain certificates from the system store.

--hkp-cacert file

Use the root certificates in file for verification of the TLS certificates used with hkps (keyserver access over TLS). If the file is in PEM format a suffix of .pem is expected for file. This option may be given multiple times to add more root certificates. Tilde expansion is supported.

If no hkp-cacert directive is present, dirmngr will use the system CAs.


3.3 Configuration

Dirmngr makes use of several directories when running in daemon mode: There are a few configuration files to control the operation of dirmngr. By default they may all be found in the current home directory (see option --homedir).

dirmngr.conf

This is the standard configuration file read by dirmngr on startup. It may contain any valid long option; the leading two dashes may not be entered and the option may not be abbreviated. This file is also read after a SIGHUP however not all options will actually have an effect. This default name may be changed on the command line (see option --options). You should backup this file.

/etc/gnupg/trusted-certs

This directory should be filled with certificates of Root CAs you are trusting in checking the CRLs and signing OCSP Responses.

Usually these are the same certificates you use with the applications making use of dirmngr. It is expected that each of these certificate files contain exactly one DER encoded certificate in a file with the suffix .crt or .der. dirmngr reads those certificates on startup and when given a SIGHUP. Certificates which are not readable or do not make up a proper X.509 certificate are ignored; see the log file for details.

Applications using dirmngr (e.g. gpgsm) can request these certificates to complete a trust chain in the same way as with the extra-certs directory (see below).

Note that for OCSP responses the certificate specified using the option --ocsp-signer is always considered valid to sign OCSP requests.

/etc/gnupg/extra-certs

This directory may contain extra certificates which are preloaded into the internal cache on startup. Applications using dirmngr (e.g. gpgsm) can request cached certificates to complete a trust chain. This is convenient in cases you have a couple intermediate CA certificates or certificates usually used to sign OCSP responses. These certificates are first tried before going out to the net to look for them. These certificates must also be DER encoded and suffixed with .crt or .der.

~/.gnupg/crls.d

This directory is used to store cached CRLs. The crls.d part will be created by dirmngr if it does not exists but you need to make sure that the upper directory exists.

Several options control the use of trusted certificates for TLS and CRLs. Here is an Overview on the use and origin of those Root CA certificates:

System

These System root certificates are used by: FIXME

The origin of the system provided certificates depends on the platform. On Windows all certificates from the Windows System Stores ROOT and CA are used.

On other platforms the certificates are read from the first file found form this list: /etc/ssl/ca-bundle.pem, /etc/ssl/certs/ca-certificates.crt, /etc/pki/tls/cert.pem, /usr/local/share/certs/ca-root-nss.crt, /etc/ssl/cert.pem.

GnuPG

The GnuPG specific certificates stored in the directory /etc/gnupg/trusted-certs are only used to validate CRLs.

OpenPGP keyserver

For accessing the OpenPGP keyservers the only certificates used are those set with the configuration option hkp-cacert.

OpenPGP keyserver pool

This is usually only one certificate read from the file /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/share/gnupg/gnupg/sks-keyservers.netCA.pem. If this certificate exists it is used to access the special keyservers hkps.pool.sks-keyservers.net (or hkps://keys.gnupg.net).

Please note that gpgsm accepts Root CA certificates for its own purposes only if they are listed in its file trustlist.txt. dirmngr does not make use of this list - except FIXME.

To be able to see diagnostics it is often useful to put at least the following lines into the configuration file ~/gnupg/dirmngr.conf:

log-file ~/dirmngr.log
verbose

You may want to check the log file to see whether all desired root CA certificates are correctly loaded.

To be able to perform OCSP requests you probably want to add the line:

allow-ocsp

To make sure that new options are read or that after the installation of a new GnuPG versions the right dirmngr version is running, you should kill an existing dirmngr so that a new instance is started as needed by the otehr components:

gpgconf --kill dirmngr

Direct interfaction with the dirmngr is possible by using the command

gpg-connect-agent --dirmngr

Enter HELP at the prompt to see a list of commands and enter HELP followed by a command name to get help on that command.


Next: , Previous: , Up: Invoking DIRMNGR   [Contents][Index]

3.4 Use of signals

A running dirmngr may be controlled by signals, i.e. using the kill command to send a signal to the process.

Here is a list of supported signals:

SIGHUP

This signal flushes all internally cached CRLs as well as any cached certificates. Then the certificate cache is reinitialized as on startup. Options are re-read from the configuration file. Instead of sending this signal it is better to use

gpgconf --reload dirmngr
SIGTERM

Shuts down the process but waits until all current requests are fulfilled. If the process has received 3 of these signals and requests are still pending, a shutdown is forced. You may also use

gpgconf --kill dirmngr

instead of this signal

SIGINT

Shuts down the process immediately.

SIGUSR1

This prints some caching statistics to the log file.


3.5 Examples

Here is an example on how to show dirmngr’s internal table of OpenPGP keyserver addresses. The output is intended for debugging purposes and not part of a defined API.

  gpg-connect-agent --dirmngr 'keyserver --hosttable' /bye

To inhibit the use of a particular host you have noticed in one of the keyserver pools, you may use

 gpg-connect-agent --dirmngr 'keyserver --dead pgpkeys.bnd.de' /bye

The description of the keyserver command can be printed using

 gpg-connect-agent --dirmngr 'help keyserver' /bye

Previous: , Up: Invoking DIRMNGR   [Contents][Index]

3.6 Dirmngr’s Assuan Protocol

Assuan is the IPC protocol used to access dirmngr. This is a description of the commands implemented by dirmngr.


3.6.1 Return the certificate(s) found

Lookup certificate. To allow multiple patterns (which are ORed) quoting is required: Spaces are to be translated into "+" or into "%20"; obviously this requires that the usual escape quoting rules are applied. The server responds with:

  S: D <DER encoded certificate>
  S: END
  S: D <second DER encoded certificate>
  S: END
  S: OK

In this example 2 certificates are returned. The server may return any number of certificates; OK will also be returned when no certificates were found. The dirmngr might return a status line

  S: S TRUNCATED <n>

To indicate that the output was truncated to N items due to a limitation of the server or by an arbitrary set limit.

The option --url may be used if instead of a search pattern a complete URL to the certificate is known:

  C: LOOKUP --url CN%3DWerner%20Koch,o%3DIntevation%20GmbH,c%3DDE?userCertificate

If the option --cache-only is given, no external lookup is done so that only certificates from the cache are returned.

With the option --single, the first and only the first match will be returned. Unless option --cache-only is also used, no local lookup will be done in this case.


3.6.2 Validate a certificate using a CRL or OCSP

  ISVALID [--only-ocsp] [--force-default-responder] certid|certfpr

Check whether the certificate described by the certid has been revoked. Due to caching, the Dirmngr is able to answer immediately in most cases.

The certid is a hex encoded string consisting of two parts, delimited by a single dot. The first part is the SHA-1 hash of the issuer name and the second part the serial number.

Alternatively the certificate’s SHA-1 fingerprint certfpr may be given in which case an OCSP request is done before consulting the CRL. If the option --only-ocsp is given, no fallback to a CRL check will be used. If the option --force-default-responder is given, only the default OCSP responder will be used and any other methods of obtaining an OCSP responder URL won’t be used.

Common return values are:

GPG_ERR_NO_ERROR (0)

This is the positive answer: The certificate is not revoked and we have an up-to-date revocation list for that certificate. If OCSP was used the responder confirmed that the certificate has not been revoked.

GPG_ERR_CERT_REVOKED

This is the negative answer: The certificate has been revoked. Either it is in a CRL and that list is up to date or an OCSP responder informed us that it has been revoked.

GPG_ERR_NO_CRL_KNOWN

No CRL is known for this certificate or the CRL is not valid or out of date.

GPG_ERR_NO_DATA

The OCSP responder returned an “unknown” status. This means that it is not aware of the certificate’s status.

GPG_ERR_NOT_SUPPORTED

This is commonly seen if OCSP support has not been enabled in the configuration.

If DirMngr has not enough information about the given certificate (which is the case for not yet cached certificates), it will inquire the missing data:

  S: INQUIRE SENDCERT <CertID>
  C: D <DER encoded certificate>
  C: END

A client should be aware that DirMngr may ask for more than one certificate.

If Dirmngr has a certificate but the signature of the certificate could not been validated because the root certificate is not known to dirmngr as trusted, it may ask back to see whether the client trusts this the root certificate:

  S: INQUIRE ISTRUSTED <CertHexfpr>
  C: D 1
  C: END

Only this answer will let Dirmngr consider the certificate as valid.


3.6.3 Validate a certificate using a CRL

Check whether the certificate with FINGERPRINT (SHA-1 hash of the entire X.509 certificate blob) is valid or not by consulting the CRL responsible for this certificate. If the fingerprint has not been given or the certificate is not known, the function inquires the certificate using:

  S: INQUIRE TARGETCERT
  C: D <DER encoded certificate>
  C: END

Thus the caller is expected to return the certificate for the request (which should match FINGERPRINT) as a binary blob. Processing then takes place without further interaction; in particular dirmngr tries to locate other required certificate by its own mechanism which includes a local certificate store as well as a list of trusted root certificates.

The return code is 0 for success; i.e. the certificate has not been revoked or one of the usual error codes from libgpg-error.


3.6.4 Validate a certificate using OCSP

  CHECKOCSP [--force-default-responder] [fingerprint]

Check whether the certificate with fingerprint (the SHA-1 hash of the entire X.509 certificate blob) is valid by consulting the appropriate OCSP responder. If the fingerprint has not been given or the certificate is not known by Dirmngr, the function inquires the certificate using:

  S: INQUIRE TARGETCERT
  C: D <DER encoded certificate>
  C: END

Thus the caller is expected to return the certificate for the request (which should match fingerprint) as a binary blob. Processing then takes place without further interaction; in particular dirmngr tries to locate other required certificates by its own mechanism which includes a local certificate store as well as a list of trusted root certificates.

If the option --force-default-responder is given, only the default OCSP responder is used. This option is the per-command variant of the global option --ignore-ocsp-service-url.

The return code is 0 for success; i.e. the certificate has not been revoked or one of the usual error codes from libgpg-error.


3.6.5 Put a certificate into the internal cache

Put a certificate into the internal cache. This command might be useful if a client knows in advance certificates required for a test and wants to make sure they get added to the internal cache. It is also helpful for debugging. To get the actual certificate, this command immediately inquires it using

  S: INQUIRE TARGETCERT
  C: D <DER encoded certificate>
  C: END

Thus the caller is expected to return the certificate for the request as a binary blob.

The return code is 0 for success; i.e. the certificate has not been successfully cached or one of the usual error codes from libgpg-error.


3.6.6 Validate a certificate for debugging

Validate a certificate using the certificate validation function used internally by dirmngr. This command is only useful for debugging. To get the actual certificate, this command immediately inquires it using

  S: INQUIRE TARGETCERT
  C: D <DER encoded certificate>
  C: END

Thus the caller is expected to return the certificate for the request as a binary blob.


4 Invoking GPG

gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool to provide digital encryption and signing services using the OpenPGP standard. gpg features complete key management and all the bells and whistles you would expect from a full OpenPGP implementation.

There are two main versions of GnuPG: GnuPG 1.x and GnuPG 2.x. GnuPG 2.x supports modern encryption algorithms and thus should be preferred over GnuPG 1.x. You only need to use GnuPG 1.x if your platform doesn’t support GnuPG 2.x, or you need support for some features that GnuPG 2.x has deprecated, e.g., decrypting data created with PGP-2 keys.

If you are looking for version 1 of GnuPG, you may find that version installed under the name gpg1.

See Option Index, for an index to gpg’s commands and options.


4.1 Commands

Commands are not distinguished from options except for the fact that only one command is allowed. Generally speaking, irrelevant options are silently ignored, and may not be checked for correctness.

gpg may be run with no commands. In this case it will print a warning perform a reasonable action depending on the type of file it is given as input (an encrypted message is decrypted, a signature is verified, a file containing keys is listed, etc.).

If you run into any problems, please add the option --verbose to the invocation to see more diagnostics.


4.1.1 Commands not specific to the function

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help
-h

Print a usage message summarizing the most useful command-line options. Note that you cannot arbitrarily abbreviate this command (though you can use its short form -h).

--warranty

Print warranty information.

--dump-options

Print a list of all available options and commands. Note that you cannot abbreviate this command.


4.1.2 Commands to select the type of operation

--sign
-s

Sign a message. This command may be combined with --encrypt (to sign and encrypt a message), --symmetric (to sign and symmetrically encrypt a message), or both --encrypt and --symmetric (to sign and encrypt a message that can be decrypted using a secret key or a passphrase). The signing key is chosen by default or can be set explicitly using the --local-user and --default-key options.

--clear-sign
--clearsign

Make a cleartext signature. The content in a cleartext signature is readable without any special software. OpenPGP software is only needed to verify the signature. cleartext signatures may modify end-of-line whitespace for platform independence and are not intended to be reversible. The signing key is chosen by default or can be set explicitly using the --local-user and --default-key options.

--detach-sign
-b

Make a detached signature.

--encrypt
-e

Encrypt data to one or more public keys. This command may be combined with --sign (to sign and encrypt a message), --symmetric (to encrypt a message that can be decrypted using a secret key or a passphrase), or --sign and --symmetric together (for a signed message that can be decrypted using a secret key or a passphrase). --recipient and related options specify which public keys to use for encryption.

--symmetric
-c

Encrypt with a symmetric cipher using a passphrase. The default symmetric cipher used is AES-128, but may be chosen with the --cipher-algo option. This command may be combined with --sign (for a signed and symmetrically encrypted message), --encrypt (for a message that may be decrypted via a secret key or a passphrase), or --sign and --encrypt together (for a signed message that may be decrypted via a secret key or a passphrase). gpg caches the passphrase used for symmetric encryption so that a decrypt operation may not require that the user needs to enter the passphrase. The option --no-symkey-cache can be used to disable this feature.

--store

Store only (make a simple literal data packet).

--decrypt
-d

Decrypt the file given on the command line (or STDIN if no file is specified) and write it to STDOUT (or the file specified with --output). If the decrypted file is signed, the signature is also verified. This command differs from the default operation, as it never writes to the filename which is included in the file and it rejects files that don’t begin with an encrypted message.

--verify

Assume that the first argument is a signed file and verify it without generating any output. With no arguments, the signature packet is read from STDIN. If only one argument is given, the specified file is expected to include a complete signature.

With more than one argument, the first argument should specify a file with a detached signature and the remaining files should contain the signed data. To read the signed data from STDIN, use ‘-’ as the second filename. For security reasons, a detached signature will not read the signed material from STDIN if not explicitly specified.

Note: If the option --batch is not used, gpg may assume that a single argument is a file with a detached signature, and it will try to find a matching data file by stripping certain suffixes. Using this historical feature to verify a detached signature is strongly discouraged; you should always specify the data file explicitly.

Note: When verifying a cleartext signature, gpg verifies only what makes up the cleartext signed data and not any extra data outside of the cleartext signature or the header lines directly following the dash marker line. The option --output may be used to write out the actual signed data, but there are other pitfalls with this format as well. It is suggested to avoid cleartext signatures in favor of detached signatures.

Note: Sometimes the use of the gpgv tool is easier than using the full-fledged gpg with this option. gpgv is designed to compare signed data against a list of trusted keys and returns with success only for a good signature. It has its own manual page.

--multifile

This modifies certain other commands to accept multiple files for processing on the command line or read from STDIN with each filename on a separate line. This allows for many files to be processed at once. --multifile may currently be used along with --verify, --encrypt, and --decrypt. Note that --multifile --verify may not be used with detached signatures.

--verify-files

Identical to --multifile --verify.

--encrypt-files

Identical to --multifile --encrypt.

--decrypt-files

Identical to --multifile --decrypt.

--list-keys
-k
--list-public-keys

List the specified keys. If no keys are specified, then all keys from the configured public keyrings are listed.

Never use the output of this command in scripts or other programs. The output is intended only for humans and its format is likely to change. The --with-colons option emits the output in a stable, machine-parseable format, which is intended for use by scripts and other programs.

--list-secret-keys
-K

List the specified secret keys. If no keys are specified, then all known secret keys are listed. A # after the initial tags sec or ssb means that the secret key or subkey is currently not usable. We also say that this key has been taken offline (for example, a primary key can be taken offline by exporting the key using the command --export-secret-subkeys). A > after these tags indicate that the key is stored on a smartcard. See also --list-keys.

--check-signatures
--check-sigs

Same as --list-keys, but the key signatures are verified and listed too. Note that for performance reasons the revocation status of a signing key is not shown. This command has the same effect as using --list-keys with --with-sig-check.

The status of the verification is indicated by a flag directly following the "sig" tag (and thus before the flags described below. A "!" indicates that the signature has been successfully verified, a "-" denotes a bad signature and a "%" is used if an error occurred while checking the signature (e.g. a non supported algorithm). Signatures where the public key is not available are not listed; to see their keyids the command --list-sigs can be used.

For each signature listed, there are several flags in between the signature status flag and keyid. These flags give additional information about each key signature. From left to right, they are the numbers 1-3 for certificate check level (see --ask-cert-level), "L" for a local or non-exportable signature (see --lsign-key), "R" for a nonRevocable signature (see the --edit-key command "nrsign"), "P" for a signature that contains a policy URL (see --cert-policy-url), "N" for a signature that contains a notation (see --cert-notation), "X" for an eXpired signature (see --ask-cert-expire), and the numbers 1-9 or "T" for 10 and above to indicate trust signature levels (see the --edit-key command "tsign").

--locate-keys
--locate-external-keys

Locate the keys given as arguments. This command basically uses the same algorithm as used when locating keys for encryption and may thus be used to see what keys gpg might use. In particular external methods as defined by --auto-key-locate are used to locate a key if the arguments comain valid mail addresses. Only public keys are listed.

The variant --locate-external-keys does not consider a locally existing key and can thus be used to force the refresh of a key via the defined external methods. If a fingerprint is given and and the methods defined by –auto-key-locate define LDAP servers, the key is fetched from these resources; defined non-LDAP keyservers are skipped.

--show-keys

This commands takes OpenPGP keys as input and prints information about them in the same way the command --list-keys does for locally stored key. In addition the list options show-unusable-uids, show-unusable-subkeys, show-notations and show-policy-urls are also enabled. As usual for automated processing, this command should be combined with the option --with-colons.

--fingerprint

List all keys (or the specified ones) along with their fingerprints. This is the same output as --list-keys but with the additional output of a line with the fingerprint. May also be combined with --check-signatures. If this command is given twice, the fingerprints of all secondary keys are listed too. This command also forces pretty printing of fingerprints if the keyid format has been set to "none".

--list-packets

List only the sequence of packets. This command is only useful for debugging. When used with option --verbose the actual MPI values are dumped and not only their lengths. Note that the output of this command may change with new releases.

--edit-card
--card-edit

Present a menu to work with a smartcard. The subcommand "help" provides an overview on available commands. For a detailed description, please see the Card HOWTO at https://gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO .

--card-status

Show the content of the smart card.

--change-pin

Present a menu to allow changing the PIN of a smartcard. This functionality is also available as the subcommand "passwd" with the --edit-card command.

--delete-keys name

Remove key from the public keyring. In batch mode either --yes is required or the key must be specified by fingerprint. This is a safeguard against accidental deletion of multiple keys. If the exclamation mark syntax is used with the fingerprint of a subkey only that subkey is deleted; if the exclamation mark is used with the fingerprint of the primary key the entire public key is deleted.

--delete-secret-keys name

Remove key from the secret keyring. In batch mode the key must be specified by fingerprint. The option --yes can be used to advise gpg-agent not to request a confirmation. This extra pre-caution is done because gpg can’t be sure that the secret key (as controlled by gpg-agent) is only used for the given OpenPGP public key. If the exclamation mark syntax is used with the fingerprint of a subkey only the secret part of that subkey is deleted; if the exclamation mark is used with the fingerprint of the primary key only the secret part of the primary key is deleted.

--delete-secret-and-public-key name

Same as --delete-key, but if a secret key exists, it will be removed first. In batch mode the key must be specified by fingerprint. The option --yes can be used to advise gpg-agent not to request a confirmation.

--export

Either export all keys from all keyrings (default keyring and those registered via option --keyring), or if at least one name is given, those of the given name. The exported keys are written to STDOUT or to the file given with option --output. Use together with --armor to mail those keys.

--send-keys keyIDs

Similar to --export but sends the keys to a keyserver. Fingerprints may be used instead of key IDs. Don’t send your complete keyring to a keyserver — select only those keys which are new or changed by you. If no keyIDs are given, gpg does nothing.

Take care: Keyservers are by design write only systems and thus it is not possible to ever delete keys once they have been send to a keyserver.

--export-secret-keys
--export-secret-subkeys

Same as --export, but exports the secret keys instead. The exported keys are written to STDOUT or to the file given with option --output. This command is often used along with the option --armor to allow for easy printing of the key for paper backup; however the external tool paperkey does a better job of creating backups on paper. Note that exporting a secret key can be a security risk if the exported keys are sent over an insecure channel.

The second form of the command has the special property to render the secret part of the primary key useless; this is a GNU extension to OpenPGP and other implementations can not be expected to successfully import such a key. Its intended use is in generating a full key with an additional signing subkey on a dedicated machine. This command then exports the key without the primary key to the main machine.

GnuPG may ask you to enter the passphrase for the key. This is required, because the internal protection method of the secret key is different from the one specified by the OpenPGP protocol.

--export-ssh-key

This command is used to export a key in the OpenSSH public key format. It requires the specification of one key by the usual means and exports the latest valid subkey which has an authentication capability to STDOUT or to the file given with option --output. That output can directly be added to ssh’s authorized_key file.

By specifying the key to export using a key ID or a fingerprint suffixed with an exclamation mark (!), a specific subkey or the primary key can be exported. This does not even require that the key has the authentication capability flag set.

--import
--fast-import

Import/merge keys. This adds the given keys to the keyring. The fast version is currently just a synonym.

There are a few other options which control how this command works. Most notable here is the --import-options merge-only option which does not insert new keys but does only the merging of new signatures, user-IDs and subkeys.

--receive-keys keyIDs
--recv-keys keyIDs

Import the keys with the given keyIDs from a keyserver.

--refresh-keys

Request updates from a keyserver for keys that already exist on the local keyring. This is useful for updating a key with the latest signatures, user IDs, etc. Calling this with no arguments will refresh the entire keyring.

--search-keys names

Search the keyserver for the given names. Multiple names given here will be joined together to create the search string for the keyserver. Note that keyservers search for names in a different and simpler way than gpg does. The best choice is to use a mail address. Due to data privacy reasons keyservers may even not even allow searching by user id or mail address and thus may only return results when being used with the --recv-key command to search by key fingerprint or keyid.

--fetch-keys URIs

Retrieve keys located at the specified URIs. Note that different installations of GnuPG may support different protocols (HTTP, FTP, LDAP, etc.). When using HTTPS the system provided root certificates are used by this command.

--update-trustdb

Do trust database maintenance. This command iterates over all keys and builds the Web of Trust. This is an interactive command because it may have to ask for the "ownertrust" values for keys. The user has to give an estimation of how far she trusts the owner of the displayed key to correctly certify (sign) other keys. GnuPG only asks for the ownertrust value if it has not yet been assigned to a key. Using the --edit-key menu, the assigned value can be changed at any time.

--check-trustdb

Do trust database maintenance without user interaction. From time to time the trust database must be updated so that expired keys or signatures and the resulting changes in the Web of Trust can be tracked. Normally, GnuPG will calculate when this is required and do it automatically unless --no-auto-check-trustdb is set. This command can be used to force a trust database check at any time. The processing is identical to that of --update-trustdb but it skips keys with a not yet defined "ownertrust".

For use with cron jobs, this command can be used together with --batch in which case the trust database check is done only if a check is needed. To force a run even in batch mode add the option --yes.

--export-ownertrust

Send the ownertrust values to STDOUT. This is useful for backup purposes as these values are the only ones which can’t be re-created from a corrupted trustdb. Example:

  gpg --export-ownertrust > otrust.txt
--import-ownertrust

Update the trustdb with the ownertrust values stored in files (or STDIN if not given); existing values will be overwritten. In case of a severely damaged trustdb and if you have a recent backup of the ownertrust values (e.g. in the file otrust.txt), you may re-create the trustdb using these commands:

  cd ~/.gnupg
  rm trustdb.gpg
  gpg --import-ownertrust < otrust.txt
--rebuild-keydb-caches

When updating from version 1.0.6 to 1.0.7 this command should be used to create signature caches in the keyring. It might be handy in other situations too.

--print-md algo
--print-mds

Print message digest of algorithm algo for all given files or STDIN. With the second form (or a deprecated "*" for algo) digests for all available algorithms are printed.

--gen-random 0|1|2 count

Emit count random bytes of the given quality level 0, 1 or 2. If count is not given or zero, an endless sequence of random bytes will be emitted. If used with --armor the output will be base64 encoded. PLEASE, don’t use this command unless you know what you are doing; it may remove precious entropy from the system!

--gen-prime mode bits

Use the source, Luke :-). The output format is subject to change with ant release.

--enarmor
--dearmor

Pack or unpack an arbitrary input into/from an OpenPGP ASCII armor. This is a GnuPG extension to OpenPGP and in general not very useful.

--unwrap

This command is similar to --decrypt with the change that the output is not the usual plaintext but the original message with the decryption layer removed. Thus the output will be an OpenPGP data structure which often means a signed OpenPGP message. Note that this command may or may not remove a compression layer which is often found beneath the encryption layer.

--tofu-policy {auto|good|unknown|bad|ask} keys

Set the TOFU policy for all the bindings associated with the specified keys. For more information about the meaning of the policies, see trust-model-tofu. The keys may be specified either by their fingerprint (preferred) or their keyid.


4.1.3 How to manage your keys

This section explains the main commands for key management.

--quick-generate-key user-id [algo [usage [expire]]]
--quick-gen-key

This is a simple command to generate a standard key with one user id. In contrast to --generate-key the key is generated directly without the need to answer a bunch of prompts. Unless the option --yes is given, the key creation will be canceled if the given user id already exists in the keyring.

If invoked directly on the console without any special options an answer to a “Continue?” style confirmation prompt is required. In case the user id already exists in the keyring a second prompt to force the creation of the key will show up.

If algo or usage are given, only the primary key is created and no prompts are shown. To specify an expiration date but still create a primary and subkey use “default” or “future-default” for algo and “default” for usage. For a description of these optional arguments see the command --quick-add-key. The usage accepts also the value “cert” which can be used to create a certification only primary key; the default is to a create certification and signing key.

The expire argument can be used to specify an expiration date for the key. Several formats are supported; commonly the ISO formats “YYYY-MM-DD” or “YYYYMMDDThhmmss” are used. To make the key expire in N seconds, N days, N weeks, N months, or N years use “seconds=N”, “Nd”, “Nw”, “Nm”, or “Ny” respectively. Not specifying a value, or using “-” results in a key expiring in a reasonable default interval. The values “never”, “none” can be used for no expiration date.

If this command is used with --batch, --pinentry-mode has been set to loopback, and one of the passphrase options (--passphrase, --passphrase-fd, or --passphrase-file) is used, the supplied passphrase is used for the new key and the agent does not ask for it. To create a key without any protection --passphrase '' may be used.

To create an OpenPGP key from the keys available on the currently inserted smartcard, the special string “card” can be used for algo. If the card features an encryption and a signing key, gpg will figure them out and creates an OpenPGP key consisting of the usual primary key and one subkey. This works only with certain smartcards. Note that the interactive --full-gen-key command allows to do the same but with greater flexibility in the selection of the smartcard keys.

Note that it is possible to create a primary key and a subkey using non-default algorithms by using “default” and changing the default parameters using the option --default-new-key-algo.

--quick-set-expire fpr expire [*|subfprs]

With two arguments given, directly set the expiration time of the primary key identified by fpr to expire. To remove the expiration time 0 can be used. With three arguments and the third given as an asterisk, the expiration time of all non-revoked and not yet expired subkeys are set to expire. With more than two arguments and a list of fingerprints given for subfprs, all non-revoked subkeys matching these fingerprints are set to expire.

--quick-add-key fpr [algo [usage [expire]]]

Directly add a subkey to the key identified by the fingerprint fpr. Without the optional arguments an encryption subkey is added. If any of the arguments are given a more specific subkey is added.

algo may be any of the supported algorithms or curve names given in the format as used by key listings. To use the default algorithm the string “default” or “-” can be used. Supported algorithms are “rsa”, “dsa”, “elg”, “ed25519”, “cv25519”, and other ECC curves. For example the string “rsa” adds an RSA key with the default key length; a string “rsa4096” requests that the key length is 4096 bits. The string “future-default” is an alias for the algorithm which will likely be used as default algorithm in future versions of gpg. To list the supported ECC curves the command gpg --with-colons --list-config curve can be used.

Depending on the given algo the subkey may either be an encryption subkey or a signing subkey. If an algorithm is capable of signing and encryption and such a subkey is desired, a usage string must be given. This string is either “default” or “-” to keep the default or a comma delimited list (or space delimited list) of keywords: “sign” for a signing subkey, “auth” for an authentication subkey, and “encr” for an encryption subkey (“encrypt” can be used as alias for “encr”). The valid combinations depend on the algorithm.

The expire argument can be used to specify an expiration date for the key. Several formats are supported; commonly the ISO formats “YYYY-MM-DD” or “YYYYMMDDThhmmss” are used. To make the key expire in N seconds, N days, N weeks, N months, or N years use “seconds=N”, “Nd”, “Nw”, “Nm”, or “Ny” respectively. Not specifying a value, or using “-” results in a key expiring in a reasonable default interval. The values “never”, “none” can be used for no expiration date.

--generate-key
--gen-key

Generate a new key pair using the current default parameters. This is the standard command to create a new key. In addition to the key a revocation certificate is created and stored in the openpgp-revocs.d directory below the GnuPG home directory.

--full-generate-key
--full-gen-key

Generate a new key pair with dialogs for all options. This is an extended version of --generate-key.

There is also a feature which allows you to create keys in batch mode. See the manual section “Unattended key generation” on how to use this.

--generate-revocation name
--gen-revoke name

Generate a revocation certificate for the complete key. To only revoke a subkey or a key signature, use the --edit command.

This command merely creates the revocation certificate so that it can be used to revoke the key if that is ever needed. To actually revoke a key the created revocation certificate needs to be merged with the key to revoke. This is done by importing the revocation certificate using the --import command. Then the revoked key needs to be published, which is best done by sending the key to a keyserver (command --send-key) and by exporting (--export) it to a file which is then send to frequent communication partners.

--generate-designated-revocation name
--desig-revoke name

Generate a designated revocation certificate for a key. This allows a user (with the permission of the keyholder) to revoke someone else’s key.

--edit-key

Present a menu which enables you to do most of the key management related tasks. It expects the specification of a key on the command line.

uid n

Toggle selection of user ID or photographic user ID with index n. Use * to select all and 0 to deselect all.

key n

Toggle selection of subkey with index n or key ID n. Use * to select all and 0 to deselect all.

sign

Make a signature on key of user name. If the key is not yet signed by the default user (or the users given with -u), the program displays the information of the key again, together with its fingerprint and asks whether it should be signed. This question is repeated for all users specified with -u.

lsign

Same as "sign" but the signature is marked as non-exportable and will therefore never be used by others. This may be used to make keys valid only in the local environment.

nrsign

Same as "sign" but the signature is marked as non-revocable and can therefore never be revoked.

tsign

Make a trust signature. This is a signature that combines the notions of certification (like a regular signature), and trust (like the "trust" command). It is generally only useful in distinct communities or groups. For more information please read the sections “Trust Signature” and “Regular Expression” in RFC-4880.

Note that "l" (for local / non-exportable), "nr" (for non-revocable, and "t" (for trust) may be freely mixed and prefixed to "sign" to create a signature of any type desired.

If the option --only-sign-text-ids is specified, then any non-text based user ids (e.g., photo IDs) will not be selected for signing.

delsig

Delete a signature. Note that it is not possible to retract a signature, once it has been send to the public (i.e. to a keyserver). In that case you better use revsig.

revsig

Revoke a signature. For every signature which has been generated by one of the secret keys, GnuPG asks whether a revocation certificate should be generated.

check

Check the signatures on all selected user IDs. With the extra option selfsig only self-signatures are shown.

adduid

Create an additional user ID.

addphoto

Create a photographic user ID. This will prompt for a JPEG file that will be embedded into the user ID. Note that a very large JPEG will make for a very large key. Also note that some programs will display your JPEG unchanged (GnuPG), and some programs will scale it to fit in a dialog box (PGP).

showphoto

Display the selected photographic user ID.

deluid

Delete a user ID or photographic user ID. Note that it is not possible to retract a user id, once it has been send to the public (i.e. to a keyserver). In that case you better use revuid.

revuid

Revoke a user ID or photographic user ID.

primary

Flag the current user id as the primary one, removes the primary user id flag from all other user ids and sets the timestamp of all affected self-signatures one second ahead. Note that setting a photo user ID as primary makes it primary over other photo user IDs, and setting a regular user ID as primary makes it primary over other regular user IDs.

keyserver

Set a preferred keyserver for the specified user ID(s). This allows other users to know where you prefer they get your key from. See --keyserver-options honor-keyserver-url for more on how this works. Setting a value of "none" removes an existing preferred keyserver.

notation

Set a name=value notation for the specified user ID(s). See --cert-notation for more on how this works. Setting a value of "none" removes all notations, setting a notation prefixed with a minus sign (-) removes that notation, and setting a notation name (without the =value) prefixed with a minus sign removes all notations with that name.

pref

List preferences from the selected user ID. This shows the actual preferences, without including any implied preferences.

showpref

More verbose preferences listing for the selected user ID. This shows the preferences in effect by including the implied preferences of 3DES (cipher), SHA-1 (digest), and Uncompressed (compression) if they are not already included in the preference list. In addition, the preferred keyserver and signature notations (if any) are shown.

setpref string

Set the list of user ID preferences to string for all (or just the selected) user IDs. Calling setpref with no arguments sets the preference list to the default (either built-in or set via --default-preference-list), and calling setpref with "none" as the argument sets an empty preference list. Use gpg --version to get a list of available algorithms. Note that while you can change the preferences on an attribute user ID (aka "photo ID"), GnuPG does not select keys via attribute user IDs so these preferences will not be used by GnuPG.

When setting preferences, you should list the algorithms in the order which you’d like to see them used by someone else when encrypting a message to your key. If you don’t include 3DES, it will be automatically added at the end. Note that there are many factors that go into choosing an algorithm (for example, your key may not be the only recipient), and so the remote OpenPGP application being used to send to you may or may not follow your exact chosen order for a given message. It will, however, only choose an algorithm that is present on the preference list of every recipient key. See also the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section below.

addkey

Add a subkey to this key.

addcardkey

Generate a subkey on a card and add it to this key.

keytocard

Transfer the selected secret subkey (or the primary key if no subkey has been selected) to a smartcard. The secret key in the keyring will be replaced by a stub if the key could be stored successfully on the card and you use the save command later. Only certain key types may be transferred to the card. A sub menu allows you to select on what card to store the key. Note that it is not possible to get that key back from the card - if the card gets broken your secret key will be lost unless you have a backup somewhere.

bkuptocard file

Restore the given file to a card. This command may be used to restore a backup key (as generated during card initialization) to a new card. In almost all cases this will be the encryption key. You should use this command only with the corresponding public key and make sure that the file given as argument is indeed the backup to restore. You should then select 2 to restore as encryption key. You will first be asked to enter the passphrase of the backup key and then for the Admin PIN of the card.

keytotpm

Transfer the selected secret subkey (or the primary key if no subkey has been selected) to TPM form. The secret key in the keyring will be replaced by the TPM representation of that key, which can only be read by the particular TPM that created it (so the keyfile now becomes locked to the laptop containing the TPM). Only certain key types may be transferred to the TPM (all TPM 2.0 systems are mandated to have the rsa2048 and nistp256 algorithms but newer TPMs may have more). Note that the key itself is not transferred into the TPM, merely encrypted by the TPM in-place, so if the keyfile is deleted, the key will be lost. Once transferred to TPM representation, the key file can never be converted back to non-TPM form and the key will die when the TPM does, so you should first have a backup on secure offline storage of the actual secret key file before conversion. It is essential to use the physical system TPM that you have rw permission on the TPM resource manager device (/dev/tpmrm0). Usually this means you must be a member of the tss group.

delkey

Remove a subkey (secondary key). Note that it is not possible to retract a subkey, once it has been send to the public (i.e. to a keyserver). In that case you better use revkey. Also note that this only deletes the public part of a key.

revkey

Revoke a subkey.

expire

Change the key or subkey expiration time. If a subkey is selected, the expiration time of this subkey will be changed. With no selection, the key expiration of the primary key is changed.

trust

Change the owner trust value for the key. This updates the trust-db immediately and no save is required.

disable
enable

Disable or enable an entire key. A disabled key can not normally be used for encryption.

addrevoker

Add a designated revoker to the key. This takes one optional argument: "sensitive". If a designated revoker is marked as sensitive, it will not be exported by default (see export-options).

passwd

Change the passphrase of the secret key.

toggle

This is dummy command which exists only for backward compatibility.

clean

Compact (by removing all signatures except the selfsig) any user ID that is no longer usable (e.g. revoked, or expired). Then, remove any signatures that are not usable by the trust calculations. Specifically, this removes any signature that does not validate, any signature that is superseded by a later signature, revoked signatures, and signatures issued by keys that are not present on the keyring.

minimize

Make the key as small as possible. This removes all signatures from each user ID except for the most recent self-signature.

change-usage

Change the usage flags (capabilities) of the primary key or of subkeys. These usage flags (e.g. Certify, Sign, Authenticate, Encrypt) are set during key creation. Sometimes it is useful to have the opportunity to change them (for example to add Authenticate) after they have been created. Please take care when doing this; the allowed usage flags depend on the key algorithm.

cross-certify

Add cross-certification signatures to signing subkeys that may not currently have them. Cross-certification signatures protect against a subtle attack against signing subkeys. See --require-cross-certification. All new keys generated have this signature by default, so this command is only useful to bring older keys up to date.

save

Save all changes to the keyring and quit.

quit

Quit the program without updating the keyring.

The listing shows you the key with its secondary keys and all user IDs. The primary user ID is indicated by a dot, and selected keys or user IDs are indicated by an asterisk. The trust value is displayed with the primary key: "trust" is the assigned owner trust and "validity" is the calculated validity of the key. Validity values are also displayed for all user IDs. For possible values of trust, see trust-values.

--sign-key name

Signs a public key with your secret key. This is a shortcut version of the subcommand "sign" from --edit-key.

--lsign-key name

Signs a public key with your secret key but marks it as non-exportable. This is a shortcut version of the subcommand "lsign" from --edit-key.

--quick-sign-key fpr [names]
--quick-lsign-key fpr [names]

Directly sign a key from the passphrase without any further user interaction. The fpr must be the verified primary fingerprint of a key in the local keyring. If no names are given, all useful user ids are signed; with given [names] only useful user ids matching one of these names are signed. By default, or if a name is prefixed with a ’*’, a case insensitive substring match is used. If a name is prefixed with a ’=’ a case sensitive exact match is done.

The command --quick-lsign-key marks the signatures as non-exportable. If such a non-exportable signature already exists the --quick-sign-key turns it into a exportable signature. If you need to update an existing signature, for example to add or change notation data, you need to use the option --force-sign-key.

This command uses reasonable defaults and thus does not provide the full flexibility of the "sign" subcommand from --edit-key. Its intended use is to help unattended key signing by utilizing a list of verified fingerprints.

--quick-add-uid user-id new-user-id

This command adds a new user id to an existing key. In contrast to the interactive sub-command adduid of --edit-key the new-user-id is added verbatim with only leading and trailing white space removed, it is expected to be UTF-8 encoded, and no checks on its form are applied.

--quick-revoke-uid user-id user-id-to-revoke

This command revokes a user ID on an existing key. It cannot be used to revoke the last user ID on key (some non-revoked user ID must remain), with revocation reason “User ID is no longer valid”. If you want to specify a different revocation reason, or to supply supplementary revocation text, you should use the interactive sub-command revuid of --edit-key.

--quick-revoke-sig fpr signing-fpr [names]

This command revokes the key signatures made by signing-fpr from the key specified by the fingerprint fpr. With names given only the signatures on user ids of the key matching any of the given names are affected (see --quick-sign-key). If a revocation already exists a notice is printed instead of creating a new revocation; no error is returned in this case. Note that key signature revocations may be superseded by a newer key signature and in turn again revoked.

--quick-set-primary-uid user-id primary-user-id

This command sets or updates the primary user ID flag on an existing key. user-id specifies the key and primary-user-id the user ID which shall be flagged as the primary user ID. The primary user ID flag is removed from all other user ids and the timestamp of all affected self-signatures is set one second ahead.

--change-passphrase user-id
--passwd user-id

Change the passphrase of the secret key belonging to the certificate specified as user-id. This is a shortcut for the sub-command passwd of the --edit-key menu. When using together with the option --dry-run this will not actually change the passphrase but check that the current passphrase is correct.


4.2 Option Summary

gpg features a bunch of options to control the exact behaviour and to change the default configuration.

Long options can be put in an options file (default "~/.gnupg/gpg.conf"). Short option names will not work - for example, "armor" is a valid option for the options file, while "a" is not. Do not write the 2 dashes, but simply the name of the option and any required arguments. Lines with a hash (’#’) as the first non-white-space character are ignored. Commands may be put in this file too, but that is not generally useful as the command will execute automatically with every execution of gpg.

Please remember that option parsing stops as soon as a non-option is encountered, you can explicitly stop parsing by using the special option --.


4.2.1 How to change the configuration

These options are used to change the configuration and most of them are usually found in the option file.

--default-key name

Use name as the default key to sign with. If this option is not used, the default key is the first key found in the secret keyring. Note that -u or --local-user overrides this option. This option may be given multiple times. In this case, the last key for which a secret key is available is used. If there is no secret key available for any of the specified values, GnuPG will not emit an error message but continue as if this option wasn’t given.

--default-recipient name

Use name as default recipient if option --recipient is not used and don’t ask if this is a valid one. name must be non-empty.

--default-recipient-self

Use the default key as default recipient if option --recipient is not used and don’t ask if this is a valid one. The default key is the first one from the secret keyring or the one set with --default-key.

--no-default-recipient

Reset --default-recipient and --default-recipient-self. Should not be used in an option file.

-v, --verbose

Give more information during processing. If used twice, the input data is listed in detail.

--no-verbose

Reset verbose level to 0. Should not be used in an option file.

-q, --quiet

Try to be as quiet as possible. Should not be used in an option file.

--batch
--no-batch

Use batch mode. Never ask, do not allow interactive commands. --no-batch disables this option. Note that even with a filename given on the command line, gpg might still need to read from STDIN (in particular if gpg figures that the input is a detached signature and no data file has been specified). Thus if you do not want to feed data via STDIN, you should connect STDIN to /dev/null.

It is highly recommended to use this option along with the options --status-fd and --with-colons for any unattended use of gpg. Should not be used in an option file.

--no-tty

Make sure that the TTY (terminal) is never used for any output. This option is needed in some cases because GnuPG sometimes prints warnings to the TTY even if --batch is used.

--yes

Assume "yes" on most questions. Should not be used in an option file.

--no

Assume "no" on most questions. Should not be used in an option file.

--list-options parameters

This is a space or comma delimited string that gives options used when listing keys and signatures (that is, --list-keys, --check-signatures, --list-public-keys, --list-secret-keys, and the --edit-key functions). Options can be prepended with a no- (after the two dashes) to give the opposite meaning. The options are:

show-photos

Causes --list-keys, --check-signatures, --list-public-keys, and --list-secret-keys to display any photo IDs attached to the key. Defaults to no. See also --photo-viewer. Does not work with --with-colons: see --attribute-fd for the appropriate way to get photo data for scripts and other frontends.

show-usage

Show usage information for keys and subkeys in the standard key listing. This is a list of letters indicating the allowed usage for a key (E=encryption, S=signing, C=certification, A=authentication). Defaults to yes.

show-policy-urls

Show policy URLs in the --check-signatures listings. Defaults to no.

show-notations
show-std-notations
show-user-notations

Show all, IETF standard, or user-defined signature notations in the --check-signatures listings. Defaults to no.

show-keyserver-urls

Show any preferred keyserver URL in the --check-signatures listings. Defaults to no.

show-uid-validity

Display the calculated validity of user IDs during key listings. Defaults to yes.

show-unusable-uids

Show revoked and expired user IDs in key listings. Defaults to no.

show-unusable-subkeys

Show revoked and expired subkeys in key listings. Defaults to no.

show-keyring

Display the keyring name at the head of key listings to show which keyring a given key resides on. Defaults to no.

show-sig-expire

Show signature expiration dates (if any) during --check-signatures listings. Defaults to no.

show-sig-subpackets

Include signature subpackets in the key listing. This option can take an optional argument list of the subpackets to list. If no argument is passed, list all subpackets. Defaults to no. This option is only meaningful when using --with-colons along with --check-signatures.

show-only-fpr-mbox

For each user-id which has a valid mail address print only the fingerprint followed by the mail address.

sort-sigs

With –list-sigs and –check-sigs sort the signatures by keyID and creation time to make it easier to view the history of these signatures. The self-signature is also listed before other signatures. Defaults to yes.

--verify-options parameters

This is a space or comma delimited string that gives options used when verifying signatures. Options can be prepended with a ‘no-’ to give the opposite meaning. The options are:

show-photos

Display any photo IDs present on the key that issued the signature. Defaults to no. See also --photo-viewer.

show-policy-urls

Show policy URLs in the signature being verified. Defaults to yes.

show-notations
show-std-notations
show-user-notations

Show all, IETF standard, or user-defined signature notations in the signature being verified. Defaults to IETF standard.

show-keyserver-urls

Show any preferred keyserver URL in the signature being verified. Defaults to yes.

show-uid-validity

Display the calculated validity of the user IDs on the key that issued the signature. Defaults to yes.

show-unusable-uids

Show revoked and expired user IDs during signature verification. Defaults to no.

show-primary-uid-only

Show only the primary user ID during signature verification. That is all the AKA lines as well as photo Ids are not shown with the signature verification status.

--enable-large-rsa
--disable-large-rsa

With –generate-key and –batch, enable the creation of RSA secret keys as large as 8192 bit. Note: 8192 bit is more than is generally recommended. These large keys don’t significantly improve security, but they are more expensive to use, and their signatures and certifications are larger. This option is only available if the binary was build with large-secmem support.

--enable-dsa2
--disable-dsa2

Enable hash truncation for all DSA keys even for old DSA Keys up to 1024 bit. This is also the default with --openpgp. Note that older versions of GnuPG also required this flag to allow the generation of DSA larger than 1024 bit.

--photo-viewer string

This is the command line that should be run to view a photo ID. "%i" will be expanded to a filename containing the photo. "%I" does the same, except the file will not be deleted once the viewer exits. Other flags are "%k" for the key ID, "%K" for the long key ID, "%f" for the key fingerprint, "%t" for the extension of the image type (e.g. "jpg"), "%T" for the MIME type of the image (e.g. "image/jpeg"), "%v" for the single-character calculated validity of the image being viewed (e.g. "f"), "%V" for the calculated validity as a string (e.g. "full"), "%U" for a base32 encoded hash of the user ID, and "%%" for an actual percent sign. If neither %i or %I are present, then the photo will be supplied to the viewer on standard input.

On Unix the default viewer is xloadimage -fork -quiet -title 'KeyID 0x%k' STDIN with a fallback to display -title 'KeyID 0x%k' %i and finally to xdg-open %i. On Windows !ShellExecute 400 %i is used; here the command is a meta command to use that API call followed by a wait time in milliseconds which is used to give the viewer time to read the temporary image file before gpg deletes it again. Note that if your image viewer program is not secure, then executing it from gpg does not make it secure.

--exec-path string

Sets a list of directories to search for photo viewers If not provided photo viewers use the PATH environment variable.

--keyring file

Add file to the current list of keyrings. If file begins with a tilde and a slash, these are replaced by the $HOME directory. If the filename does not contain a slash, it is assumed to be in the GnuPG home directory ("~/.gnupg" unless --homedir or $GNUPGHOME is used).

Note that this adds a keyring to the current list. If the intent is to use the specified keyring alone, use --keyring along with --no-default-keyring.

If the option --no-keyring has been used no keyrings will be used at all.

Note that if the option use-keyboxd is enabled in common.conf, no keyrings are used at all and keys are all maintained by the keyboxd process in its own database.

--primary-keyring file

This is a varian of --keyring and designates file as the primary public keyring. This means that newly imported keys (via --import or keyserver --recv-from) will go to this keyring.

--secret-keyring file

This is an obsolete option and ignored. All secret keys are stored in the private-keys-v1.d directory below the GnuPG home directory.

--trustdb-name file

Use file instead of the default trustdb. If file begins with a tilde and a slash, these are replaced by the $HOME directory. If the filename does not contain a slash, it is assumed to be in the GnuPG home directory (~/.gnupg if --homedir or $GNUPGHOME is not used).

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

--display-charset name

Set the name of the native character set. This is used to convert some informational strings like user IDs to the proper UTF-8 encoding. Note that this has nothing to do with the character set of data to be encrypted or signed; GnuPG does not recode user-supplied data. If this option is not used, the default character set is determined from the current locale. A verbosity level of 3 shows the chosen set. This option should not be used on Windows. Valid values for name are:

iso-8859-1

This is the Latin 1 set.

iso-8859-2

The Latin 2 set.

iso-8859-15

This is currently an alias for the Latin 1 set.

koi8-r

The usual Russian set (RFC-1489).

utf-8

Bypass all translations and assume that the OS uses native UTF-8 encoding.

--utf8-strings
--no-utf8-strings

Assume that command line arguments are given as UTF-8 strings. The default (--no-utf8-strings) is to assume that arguments are encoded in the character set as specified by --display-charset. These options affect all following arguments. Both options may be used multiple times. This option should not be used in an option file.

This option has no effect on Windows. There the internal used UTF-8 encoding is translated for console input and output. The command line arguments are expected as Unicode and translated to UTF-8. Thus when calling this program from another, make sure to use the Unicode version of CreateProcess.

--options file

Read options from file and do not try to read them from the default options file in the homedir (see --homedir). This option is ignored if used in an options file.

--no-options

Shortcut for --options /dev/null. This option is detected before an attempt to open an option file. Using this option will also prevent the creation of a ~/.gnupg homedir.

-z n
--compress-level n
--bzip2-compress-level n

Set compression level to n for the ZIP and ZLIB compression algorithms. The default is to use the default compression level of zlib (normally 6). --bzip2-compress-level sets the compression level for the BZIP2 compression algorithm (defaulting to 6 as well). This is a different option from --compress-level since BZIP2 uses a significant amount of memory for each additional compression level. -z sets both. A value of 0 for n disables compression.

--bzip2-decompress-lowmem

Use a different decompression method for BZIP2 compressed files. This alternate method uses a bit more than half the memory, but also runs at half the speed. This is useful under extreme low memory circumstances when the file was originally compressed at a high --bzip2-compress-level.

--mangle-dos-filenames
--no-mangle-dos-filenames

Older version of Windows cannot handle filenames with more than one dot. --mangle-dos-filenames causes GnuPG to replace (rather than add to) the extension of an output filename to avoid this problem. This option is off by default and has no effect on non-Windows platforms.

--ask-cert-level
--no-ask-cert-level

When making a key signature, prompt for a certification level. If this option is not specified, the certification level used is set via --default-cert-level. See --default-cert-level for information on the specific levels and how they are used. --no-ask-cert-level disables this option. This option defaults to no.

--default-cert-level n

The default to use for the check level when signing a key.

0 means you make no particular claim as to how carefully you verified the key.

1 means you believe the key is owned by the person who claims to own it but you could not, or did not verify the key at all. This is useful for a "persona" verification, where you sign the key of a pseudonymous user.

2 means you did casual verification of the key. For example, this could mean that you verified the key fingerprint and checked the user ID on the key against a photo ID.

3 means you did extensive verification of the key. For example, this could mean that you verified the key fingerprint with the owner of the key in person, and that you checked, by means of a hard to forge document with a photo ID (such as a passport) that the name of the key owner matches the name in the user ID on the key, and finally that you verified (by exchange of email) that the email address on the key belongs to the key owner.

Note that the examples given above for levels 2 and 3 are just that: examples. In the end, it is up to you to decide just what "casual" and "extensive" mean to you.

This option defaults to 0 (no particular claim).

--min-cert-level

When building the trust database, treat any signatures with a certification level below this as invalid. Defaults to 2, which disregards level 1 signatures. Note that level 0 "no particular claim" signatures are always accepted.

--trusted-key long key ID or fingerprint

Assume that the specified key (which should be given as fingerprint) is as trustworthy as one of your own secret keys. This option is useful if you don’t want to keep your secret keys (or one of them) online but still want to be able to check the validity of a given recipient’s or signator’s key. If the given key is not locally available but an LDAP keyserver is configured the missing key is imported from that server.

--trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}

Set what trust model GnuPG should follow. The models are:

pgp

This is the Web of Trust combined with trust signatures as used in PGP 5.x and later. This is the default trust model when creating a new trust database.

classic

This is the standard Web of Trust as introduced by PGP 2.

tofu

TOFU stands for Trust On First Use. In this trust model, the first time a key is seen, it is memorized. If later another key with a user id with the same email address is seen, both keys are marked as suspect. In that case, the next time either is used, a warning is displayed describing the conflict, why it might have occurred (either the user generated a new key and failed to cross sign the old and new keys, the key is forgery, or a man-in-the-middle attack is being attempted), and the user is prompted to manually confirm the validity of the key in question.

Because a potential attacker is able to control the email address and thereby circumvent the conflict detection algorithm by using an email address that is similar in appearance to a trusted email address, whenever a message is verified, statistics about the number of messages signed with the key are shown. In this way, a user can easily identify attacks using fake keys for regular correspondents.

When compared with the Web of Trust, TOFU offers significantly weaker security guarantees. In particular, TOFU only helps ensure consistency (that is, that the binding between a key and email address doesn’t change). A major advantage of TOFU is that it requires little maintenance to use correctly. To use the web of trust properly, you need to actively sign keys and mark users as trusted introducers. This is a time-consuming process and anecdotal evidence suggests that even security-conscious users rarely take the time to do this thoroughly and instead rely on an ad-hoc TOFU process.

In the TOFU model, policies are associated with bindings between keys and email addresses (which are extracted from user ids and normalized). There are five policies, which can be set manually using the --tofu-policy option. The default policy can be set using the --tofu-default-policy option.

The TOFU policies are: auto, good, unknown, bad and ask. The auto policy is used by default (unless overridden by --tofu-default-policy) and marks a binding as marginally trusted. The good, unknown and bad policies mark a binding as fully trusted, as having unknown trust or as having trust never, respectively. The unknown policy is useful for just using TOFU to detect conflicts, but to never assign positive trust to a binding. The final policy, ask prompts the user to indicate the binding’s trust. If batch mode is enabled (or input is inappropriate in the context), then the user is not prompted and the undefined trust level is returned.

tofu+pgp

This trust model combines TOFU with the Web of Trust. This is done by computing the trust level for each model and then taking the maximum trust level where the trust levels are ordered as follows: unknown < undefined < marginal < fully < ultimate < expired < never.

By setting --tofu-default-policy=unknown, this model can be used to implement the web of trust with TOFU’s conflict detection algorithm, but without its assignment of positive trust values, which some security-conscious users don’t like.

direct

Key validity is set directly by the user and not calculated via the Web of Trust. This model is solely based on the key and does not distinguish user IDs. Note that when changing to another trust model the trust values assigned to a key are transformed into ownertrust values, which also indicate how you trust the owner of the key to sign other keys.

always

Skip key validation and assume that used keys are always fully valid. You generally won’t use this unless you are using some external validation scheme. This option also suppresses the "[uncertain]" tag printed with signature checks when there is no evidence that the user ID is bound to the key. Note that this trust model still does not allow the use of expired, revoked, or disabled keys.

auto

Select the trust model depending on whatever the internal trust database says. This is the default model if such a database already exists. Note that a tofu trust model is not considered here and must be enabled explicitly.

--auto-key-locate mechanisms
--no-auto-key-locate

GnuPG can automatically locate and retrieve keys as needed using this option. This happens when encrypting to an email address (in the "user@example.com" form), and there are no "user@example.com" keys on the local keyring. This option takes any number of the mechanisms listed below, in the order they are to be tried. Instead of listing the mechanisms as comma delimited arguments, the option may also be given several times to add more mechanism. The option --no-auto-key-locate or the mechanism "clear" resets the list. The default is "local,wkd".

cert

Locate a key using DNS CERT, as specified in RFC-4398.

dane

Locate a key using DANE, as specified in draft-ietf-dane-openpgpkey-05.txt.

wkd

Locate a key using the Web Key Directory protocol.

ldap

Using DNS Service Discovery, check the domain in question for any LDAP keyservers to use. If this fails, attempt to locate the key using the PGP Universal method of checking ‘ldap://keys.(thedomain)’.

ntds

Locate the key using the Active Directory (Windows only). This method also allows to search by fingerprint using the command --locate-external-key. Note that this mechanism is actually a shortcut for the mechanism ‘keyserver’ but using "ldap:///" as the keyserver.

keyserver

Locate a key using a keyserver. This method also allows to search by fingerprint using the command --locate-external-key if any of the configured keyservers is an LDAP server.

keyserver-URL

In addition, a keyserver URL as used in the dirmngr configuration may be used here to query that particular keyserver. This method also allows to search by fingerprint using the command --locate-external-key if the URL specifies an LDAP server.

local

Locate the key using the local keyrings. This mechanism allows the user to select the order a local key lookup is done. Thus using ‘--auto-key-locate local’ is identical to --no-auto-key-locate.

nodefault

This flag disables the standard local key lookup, done before any of the mechanisms defined by the --auto-key-locate are tried. The position of this mechanism in the list does not matter. It is not required if local is also used.

clear

Clear all defined mechanisms. This is useful to override mechanisms given in a config file. Note that a nodefault in mechanisms will also be cleared unless it is given after the clear.

--auto-key-import
--no-auto-key-import

This is an offline mechanism to get a missing key for signature verification and for later encryption to this key. If this option is enabled and a signature includes an embedded key, that key is used to verify the signature and on verification success the key is imported. The default is --no-auto-key-import.

On the sender (signing) site the option --include-key-block needs to be used to put the public part of the signing key as “Key Block subpacket” into the signature.

--auto-key-retrieve
--no-auto-key-retrieve

These options enable or disable the automatic retrieving of keys from a keyserver when verifying signatures made by keys that are not on the local keyring. The default is --no-auto-key-retrieve.

The order of methods tried to lookup the key is:

1. If the option --auto-key-import is set and the signatures includes an embedded key, that key is used to verify the signature and on verification success that key is imported.

2. If a preferred keyserver is specified in the signature and the option honor-keyserver-url is active (which is not the default), that keyserver is tried. Note that the creator of the signature uses the option --sig-keyserver-url to specify the preferred keyserver for data signatures.

3. If the signature has the Signer’s UID set (e.g. using --sender while creating the signature) a Web Key Directory (WKD) lookup is done. This is the default configuration but can be disabled by removing WKD from the auto-key-locate list or by using the option --disable-signer-uid.

4. If any keyserver is configured and the Issuer Fingerprint is part of the signature (since GnuPG 2.1.16), the configured keyservers are tried.

Note that this option makes a "web bug" like behavior possible. Keyserver or Web Key Directory operators can see which keys you request, so by sending you a message signed by a brand new key (which you naturally will not have on your local keyring), the operator can tell both your IP address and the time when you verified the signature.

--keyid-format {none|short|0xshort|long|0xlong}

Select how to display key IDs. "none" does not show the key ID at all but shows the fingerprint in a separate line. "short" is the traditional 8-character key ID. "long" is the more accurate (but less convenient) 16-character key ID. Add an "0x" to either to include an "0x" at the beginning of the key ID, as in 0x99242560. Note that this option is ignored if the option --with-colons is used.

--keyserver name

This option is deprecated - please use the --keyserver in dirmngr.conf instead.

Use name as your keyserver. This is the server that --receive-keys, --send-keys, and --search-keys will communicate with to receive keys from, send keys to, and search for keys on. The format of the name is a URI: ‘scheme:[//]keyservername[:port]’ The scheme is the type of keyserver: "hkp"/"hkps" for the HTTP (or compatible) keyservers or "ldap"/"ldaps" for the LDAP keyservers. Note that your particular installation of GnuPG may have other keyserver types available as well. Keyserver schemes are case-insensitive.

Most keyservers synchronize with each other, so there is generally no need to send keys to more than one server. The keyserver hkp://keys.gnupg.net uses round robin DNS to give a different keyserver each time you use it.

--keyserver-options {name=value}

This is a space or comma delimited string that gives options for the keyserver. Options can be prefixed with a ‘no-’ to give the opposite meaning. Valid import-options or export-options may be used here as well to apply to importing (--recv-key) or exporting (--send-key) a key from a keyserver. While not all options are available for all keyserver types, some common options are:

include-revoked

When searching for a key with --search-keys, include keys that are marked on the keyserver as revoked. Note that not all keyservers differentiate between revoked and unrevoked keys, and for such keyservers this option is meaningless. Note also that most keyservers do not have cryptographic verification of key revocations, and so turning this option off may result in skipping keys that are incorrectly marked as revoked.

include-disabled

When searching for a key with --search-keys, include keys that are marked on the keyserver as disabled. Note that this option is not used with HKP keyservers.

auto-key-retrieve

This is an obsolete alias for the option auto-key-retrieve. Please do not use it; it will be removed in future versions..

honor-keyserver-url

When using --refresh-keys, if the key in question has a preferred keyserver URL, then use that preferred keyserver to refresh the key from. In addition, if auto-key-retrieve is set, and the signature being verified has a preferred keyserver URL, then use that preferred keyserver to fetch the key from. Note that this option introduces a "web bug": The creator of the key can see when the keys is refreshed. Thus this option is not enabled by default.

include-subkeys

When receiving a key, include subkeys as potential targets. Note that this option is not used with HKP keyservers, as they do not support retrieving keys by subkey id.

timeout
http-proxy=value
verbose
debug
check-cert
ca-cert-file

These options have no more function since GnuPG 2.1. Use the dirmngr configuration options instead.

The default list of options is: "self-sigs-only, import-clean, repair-keys, repair-pks-subkey-bug, export-attributes". However, if the actual used source is an LDAP server "no-self-sigs-only" is assumed unless "self-sigs-only" has been explictly configured.

--completes-needed n

Number of completely trusted users to introduce a new key signer (defaults to 1).

--marginals-needed n

Number of marginally trusted users to introduce a new key signer (defaults to 3)

--tofu-default-policy {auto|good|unknown|bad|ask}

The default TOFU policy (defaults to auto). For more information about the meaning of this option, see trust-model-tofu.

--max-cert-depth n

Maximum depth of a certification chain (default is 5).

--no-sig-cache

Do not cache the verification status of key signatures. Caching gives a much better performance in key listings. However, if you suspect that your public keyring is not safe against write modifications, you can use this option to disable the caching. It probably does not make sense to disable it because all kind of damage can be done if someone else has write access to your public keyring.

--auto-check-trustdb
--no-auto-check-trustdb

If GnuPG feels that its information about the Web of Trust has to be updated, it automatically runs the --check-trustdb command internally. This may be a time consuming process. --no-auto-check-trustdb disables this option.

--use-agent
--no-use-agent

This is dummy option. gpg always requires the agent.

--gpg-agent-info

This is dummy option. It has no effect when used with gpg.

--agent-program file

Specify an agent program to be used for secret key operations. The default value is determined by running gpgconf with the option --list-dirs. Note that the pipe symbol (|) is used for a regression test suite hack and may thus not be used in the file name.

--dirmngr-program file

Specify a dirmngr program to be used for keyserver access. The default value is /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/bin/dirmngr.

--disable-dirmngr

Entirely disable the use of the Dirmngr.

--no-autostart

Do not start the gpg-agent or the dirmngr if it has not yet been started and its service is required. This option is mostly useful on machines where the connection to gpg-agent has been redirected to another machines. If dirmngr is required on the remote machine, it may be started manually using gpgconf --launch dirmngr.

--lock-once

Lock the databases the first time a lock is requested and do not release the lock until the process terminates.

--lock-multiple

Release the locks every time a lock is no longer needed. Use this to override a previous --lock-once from a config file.

--lock-never

Disable locking entirely. This option should be used only in very special environments, where it can be assured that only one process is accessing those files. A bootable floppy with a stand-alone encryption system will probably use this. Improper usage of this option may lead to data and key corruption.

--exit-on-status-write-error

This option will cause write errors on the status FD to immediately terminate the process. That should in fact be the default but it never worked this way and thus we need an option to enable this, so that the change won’t break applications which close their end of a status fd connected pipe too early. Using this option along with --enable-progress-filter may be used to cleanly cancel long running gpg operations.

--limit-card-insert-tries n

With n greater than 0 the number of prompts asking to insert a smartcard gets limited to N-1. Thus with a value of 1 gpg won’t at all ask to insert a card if none has been inserted at startup. This option is useful in the configuration file in case an application does not know about the smartcard support and waits ad infinitum for an inserted card.

--no-random-seed-file

GnuPG uses a file to store its internal random pool over invocations. This makes random generation faster; however sometimes write operations are not desired. This option can be used to achieve that with the cost of slower random generation.

--no-greeting

Suppress the initial copyright message.

--no-secmem-warning

Suppress the warning about "using insecure memory".

--no-permission-warning

Suppress the warning about unsafe file and home directory (--homedir) permissions. Note that the permission checks that GnuPG performs are not intended to be authoritative, but rather they simply warn about certain common permission problems. Do not assume that the lack of a warning means that your system is secure.

Note that the warning for unsafe --homedir permissions cannot be suppressed in the gpg.conf file, as this would allow an attacker to place an unsafe gpg.conf file in place, and use this file to suppress warnings about itself. The --homedir permissions warning may only be suppressed on the command line.

--require-secmem
--no-require-secmem

Refuse to run if GnuPG cannot get secure memory. Defaults to no (i.e. run, but give a warning).

--require-cross-certification
--no-require-cross-certification

When verifying a signature made from a subkey, ensure that the cross certification "back signature" on the subkey is present and valid. This protects against a subtle attack against subkeys that can sign. Defaults to --require-cross-certification for gpg.

--expert
--no-expert

Allow the user to do certain nonsensical or "silly" things like signing an expired or revoked key, or certain potentially incompatible things like generating unusual key types. This also disables certain warning messages about potentially incompatible actions. As the name implies, this option is for experts only. If you don’t fully understand the implications of what it allows you to do, leave this off. --no-expert disables this option.


4.2.3 Input and Output

--armor
-a

Create ASCII armored output. The default is to create the binary OpenPGP format.

--no-armor

Assume the input data is not in ASCII armored format.

--output file
-o file

Write output to file. To write to stdout use - as the filename.

--max-output n

This option sets a limit on the number of bytes that will be generated when processing a file. Since OpenPGP supports various levels of compression, it is possible that the plaintext of a given message may be significantly larger than the original OpenPGP message. While GnuPG works properly with such messages, there is often a desire to set a maximum file size that will be generated before processing is forced to stop by the OS limits. Defaults to 0, which means "no limit".

--chunk-size n

The AEAD encryption mode encrypts the data in chunks so that a receiving side can check for transmission errors or tampering at the end of each chunk and does not need to delay this until all data has been received. The used chunk size is 2^n byte. The lowest allowed value for n is 6 (64 byte) and the largest is the default of 22 which creates chunks not larger than 4 MiB.

--input-size-hint n

This option can be used to tell GPG the size of the input data in bytes. n must be a positive base-10 number. This option is only useful if the input is not taken from a file. GPG may use this hint to optimize its buffer allocation strategy. It is also used by the --status-fd line “PROGRESS” to provide a value for “total” if that is not available by other means.

--key-origin string[,url]

gpg can track the origin of a key. Certain origins are implicitly known (e.g. keyserver, web key directory) and set. For a standard import the origin of the keys imported can be set with this option. To list the possible values use "help" for string. Some origins can store an optional url argument. That URL can appended to string after a comma.

--import-options parameters

This is a space or comma delimited string that gives options for importing keys. Options can be prepended with a ‘no-’ to give the opposite meaning. The options are:

import-local-sigs

Allow importing key signatures marked as "local". This is not generally useful unless a shared keyring scheme is being used. Defaults to no.

keep-ownertrust

Normally possible still existing ownertrust values of a key are cleared if a key is imported. This is in general desirable so that a formerly deleted key does not automatically gain an ownertrust values merely due to import. On the other hand it is sometimes necessary to re-import a trusted set of keys again but keeping already assigned ownertrust values. This can be achieved by using this option.

repair-pks-subkey-bug

During import, attempt to repair the damage caused by the PKS keyserver bug (pre version 0.9.6) that mangles keys with multiple subkeys. Note that this cannot completely repair the damaged key as some crucial data is removed by the keyserver, but it does at least give you back one subkey. Defaults to no for regular --import and to yes for keyserver --receive-keys.

import-show
show-only

Show a listing of the key as imported right before it is stored. This can be combined with the option --dry-run to only look at keys; the option show-only is a shortcut for this combination. The command --show-keys is another shortcut for this. Note that suffixes like ’#’ for "sec" and "sbb" lines may or may not be printed.

import-export

Run the entire import code but instead of storing the key to the local keyring write it to the output. The export option export-dane affect the output. This option can for example be used to remove all invalid parts from a key without the need to store it.

merge-only

During import, allow key updates to existing keys, but do not allow any new keys to be imported. Defaults to no.

import-clean

After import, compact (remove all signatures except the self-signature) any user IDs from the new key that are not usable. Then, remove any signatures from the new key that are not usable. This includes signatures that were issued by keys that are not present on the keyring. This option is the same as running the --edit-key command "clean" after import. Defaults to no.

self-sigs-only

Accept only self-signatures while importing a key. All other key signatures are skipped at an early import stage. This option can be used with keyserver-options to mitigate attempts to flood a key with bogus signatures from a keyserver. The drawback is that all other valid key signatures, as required by the Web of Trust are also not imported. Note that when using this option along with import-clean it suppresses the final clean step after merging the imported key into the existing key.

repair-keys

After import, fix various problems with the keys. For example, this reorders signatures, and strips duplicate signatures. Defaults to yes.

bulk-import

When used the keyboxd (option use-keyboxd in common.conf) does the import within a single transaction.

import-minimal

Import the smallest key possible. This removes all signatures except the most recent self-signature on each user ID. This option is the same as running the --edit-key command "minimize" after import. Defaults to no.

restore
import-restore

Import in key restore mode. This imports all data which is usually skipped during import; including all GnuPG specific data. All other contradicting options are overridden.

--import-filter {name=expr}
--export-filter {name=expr}

These options define an import/export filter which are applied to the imported/exported keyblock right before it will be stored/written. name defines the type of filter to use, expr the expression to evaluate. The option can be used several times which then appends more expression to the same name.

The available filter types are:

keep-uid

This filter will keep a user id packet and its dependent packets in the keyblock if the expression evaluates to true.

drop-subkey

This filter drops the selected subkeys. Currently only implemented for –export-filter.

drop-sig

This filter drops the selected key signatures on user ids. Self-signatures are not considered. Currently only implemented for –import-filter.

For the syntax of the expression see the chapter "FILTER EXPRESSIONS". The property names for the expressions depend on the actual filter type and are indicated in the following table.

The available properties are:

uid

A string with the user id. (keep-uid)

mbox

The addr-spec part of a user id with mailbox or the empty string. (keep-uid)

key_algo

A number with the public key algorithm of a key or subkey packet. (drop-subkey)

key_created
key_created_d

The first is the timestamp a public key or subkey packet was created. The second is the same but given as an ISO string, e.g. "2016-08-17". (drop-subkey)

fpr

The hexified fingerprint of the current subkey or primary key. (drop-subkey)

primary

Boolean indicating whether the user id is the primary one. (keep-uid)

expired

Boolean indicating whether a user id (keep-uid), a key (drop-subkey), or a signature (drop-sig) expired.

revoked

Boolean indicating whether a user id (keep-uid) or a key (drop-subkey) has been revoked.

disabled

Boolean indicating whether a primary key is disabled. (not used)

secret

Boolean indicating whether a key or subkey is a secret one. (drop-subkey)

usage

A string indicating the usage flags for the subkey, from the sequence “ecsa?”. For example, a subkey capable of just signing and authentication would be an exact match for “sa”. (drop-subkey)

sig_created
sig_created_d

The first is the timestamp a signature packet was created. The second is the same but given as an ISO date string, e.g. "2016-08-17". (drop-sig)

sig_algo

A number with the public key algorithm of a signature packet. (drop-sig)

sig_digest_algo

A number with the digest algorithm of a signature packet. (drop-sig)

--export-options parameters

This is a space or comma delimited string that gives options for exporting keys. Options can be prepended with a ‘no-’ to give the opposite meaning. The options are:

export-local-sigs

Allow exporting key signatures marked as "local". This is not generally useful unless a shared keyring scheme is being used. Defaults to no.

export-attributes

Include attribute user IDs (photo IDs) while exporting. Not including attribute user IDs is useful to export keys that are going to be used by an OpenPGP program that does not accept attribute user IDs. Defaults to yes.

export-sensitive-revkeys

Include designated revoker information that was marked as "sensitive". Defaults to no.

backup
export-backup

Export for use as a backup. The exported data includes all data which is needed to restore the key or keys later with GnuPG. The format is basically the OpenPGP format but enhanced with GnuPG specific data. All other contradicting options are overridden.

export-clean

Compact (remove all signatures from) user IDs on the key being exported if the user IDs are not usable. Also, do not export any signatures that are not usable. This includes signatures that were issued by keys that are not present on the keyring. This option is the same as running the --edit-key command "clean" before export except that the local copy of the key is not modified. Defaults to no.

export-minimal

Export the smallest key possible. This removes all signatures except the most recent self-signature on each user ID. This option is the same as running the --edit-key command "minimize" before export except that the local copy of the key is not modified. Defaults to no.

export-dane

Instead of outputting the key material output OpenPGP DANE records suitable to put into DNS zone files. An ORIGIN line is printed before each record to allow diverting the records to the corresponding zone file.

--with-colons

Print key listings delimited by colons. Note that the output will be encoded in UTF-8 regardless of any --display-charset setting. This format is useful when GnuPG is called from scripts and other programs as it is easily machine parsed. The details of this format are documented in the file doc/DETAILS, which is included in the GnuPG source distribution.

--fixed-list-mode

Do not merge primary user ID and primary key in --with-colon listing mode and print all timestamps as seconds since 1970-01-01. Since GnuPG 2.0.10, this mode is always used and thus this option is obsolete; it does not harm to use it though.

--legacy-list-mode

Revert to the pre-2.1 public key list mode. This only affects the human readable output and not the machine interface (i.e. --with-colons). Note that the legacy format does not convey suitable information for elliptic curves.

--with-fingerprint

Same as the command --fingerprint but changes only the format of the output and may be used together with another command.

--with-subkey-fingerprint

If a fingerprint is printed for the primary key, this option forces printing of the fingerprint for all subkeys. This could also be achieved by using the --with-fingerprint twice but by using this option along with keyid-format "none" a compact fingerprint is printed.

--with-icao-spelling

Print the ICAO spelling of the fingerprint in addition to the hex digits.

--with-keygrip

Include the keygrip in the key listings. In --with-colons mode this is implicitly enable for secret keys.

--with-key-origin

Include the locally held information on the origin and last update of a key in a key listing. In --with-colons mode this is always printed. This data is currently experimental and shall not be considered part of the stable API.

--with-wkd-hash

Print a Web Key Directory identifier along with each user ID in key listings. This is an experimental feature and semantics may change.

--with-secret

Include info about the presence of a secret key in public key listings done with --with-colons.


4.2.4 OpenPGP protocol specific options

-t, --textmode
--no-textmode

Treat input files as text and store them in the OpenPGP canonical text form with standard "CRLF" line endings. This also sets the necessary flags to inform the recipient that the encrypted or signed data is text and may need its line endings converted back to whatever the local system uses. This option is useful when communicating between two platforms that have different line ending conventions (UNIX-like to Mac, Mac to Windows, etc). --no-textmode disables this option, and is the default.

--force-v3-sigs
--no-force-v3-sigs
--force-v4-certs
--no-force-v4-certs

These options are obsolete and have no effect since GnuPG 2.1.

--force-aead

Force the use of AEAD encryption over MDC encryption. AEAD is a modern and faster way to do authenticated encryption than the old MDC method. See also options --aead-algo and --chunk-size.

--force-mdc
--disable-mdc

These options are obsolete and have no effect since GnuPG 2.2.8. The MDC is always used unless the keys indicate that an AEAD algorithm can be used in which case AEAD is used. But note: If the creation of a legacy non-MDC message is exceptionally required, the option --rfc2440 allows for this.

--disable-signer-uid

By default the user ID of the signing key is embedded in the data signature. As of now this is only done if the signing key has been specified with local-user using a mail address, or with sender. This information can be helpful for verifier to locate the key; see option --auto-key-retrieve.

--include-key-block
--no-include-key-block

This option is used to embed the actual signing key into a data signature. The embedded key is stripped down to a single user id and includes only the signing subkey used to create the signature as well as as valid encryption subkeys. All other info is removed from the key to keep it and thus the signature small. This option is the OpenPGP counterpart to the gpgsm option --include-certs and allows the recipient of a signed message to reply encrypted to the sender without using any online directories to lookup the key. The default is --no-include-key-block. See also the option --auto-key-import.

--personal-cipher-preferences string

Set the list of personal cipher preferences to string. Use gpg --version to get a list of available algorithms, and use none to set no preference at all. This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients. The most highly ranked cipher in this list is also used for the --symmetric encryption command.

--personal-aead-preferences string

Set the list of personal AEAD preferences to string. Use gpg --version to get a list of available algorithms, and use none to set no preference at all. This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients. The most highly ranked cipher in this list is also used for the --symmetric encryption command.

--personal-digest-preferences string

Set the list of personal digest preferences to string. Use gpg --version to get a list of available algorithms, and use none to set no preference at all. This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients. The most highly ranked digest algorithm in this list is also used when signing without encryption (e.g. --clear-sign or --sign).

--personal-compress-preferences string

Set the list of personal compression preferences to string. Use gpg --version to get a list of available algorithms, and use none to set no preference at all. This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients. The most highly ranked compression algorithm in this list is also used when there are no recipient keys to consider (e.g. --symmetric).

--s2k-cipher-algo name

Use name as the cipher algorithm for symmetric encryption with a passphrase if --personal-cipher-preferences and --cipher-algo are not given. The default is AES-128.

--s2k-digest-algo name

Use name as the digest algorithm used to mangle the passphrases for symmetric encryption. The default is SHA-1.

--s2k-mode n

Selects how passphrases for symmetric encryption are mangled. If n is 0 a plain passphrase (which is in general not recommended) will be used, a 1 adds a salt (which should not be used) to the passphrase and a 3 (the default) iterates the whole process a number of times (see --s2k-count).

--s2k-count n

Specify how many times the passphrases mangling for symmetric encryption is repeated. This value may range between 1024 and 65011712 inclusive. The default is inquired from gpg-agent. Note that not all values in the 1024-65011712 range are legal and if an illegal value is selected, GnuPG will round up to the nearest legal value. This option is only meaningful if --s2k-mode is set to the default of 3.


4.2.5 Compliance options

These options control what GnuPG is compliant to. Only one of these options may be active at a time. Note that the default setting of this is nearly always the correct one. See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section below before using one of these options.

--gnupg

Use standard GnuPG behavior. This is essentially OpenPGP behavior (see --openpgp), but with extension from the proposed update to OpenPGP and with some additional workarounds for common compatibility problems in different versions of PGP. This is the default option, so it is not generally needed, but it may be useful to override a different compliance option in the gpg.conf file.

--openpgp

Reset all packet, cipher and digest options to strict OpenPGP behavior. This option implies --allow-old-cipher-algos. Use this option to reset all previous options like --s2k-*, --cipher-algo, --digest-algo and --compress-algo to OpenPGP compliant values. All PGP workarounds are disabled.

--rfc4880

Reset all packet, cipher and digest options to strict RFC-4880 behavior. This option implies --allow-old-cipher-algos. Note that this is currently the same thing as --openpgp.

--rfc4880bis

Reset all packet, cipher and digest options to strict according to the proposed updates of RFC-4880.

--rfc2440

Reset all packet, cipher and digest options to strict RFC-2440 behavior. Note that by using this option encryption packets are created in a legacy mode without MDC protection. This is dangerous and should thus only be used for experiments. This option implies --allow-old-cipher-algos. See also option --ignore-mdc-error.

--pgp6

This option is obsolete; it is handled as an alias for --pgp7

--pgp7

Set up all options to be as PGP 7 compliant as possible. This allowed the ciphers IDEA, 3DES, CAST5,AES128, AES192, AES256, and TWOFISH., the hashes MD5, SHA1 and RIPEMD160, and the compression algorithms none and ZIP. This option implies --escape-from-lines and disables --throw-keyids,

--pgp8

Set up all options to be as PGP 8 compliant as possible. PGP 8 is a lot closer to the OpenPGP standard than previous versions of PGP, so all this does is disable --throw-keyids and set --escape-from-lines. All algorithms are allowed except for the SHA224, SHA384, and SHA512 digests.

--compliance string

This option can be used instead of one of the options above. Valid values for string are the above option names (without the double dash) and possibly others as shown when using "help" for string.

--min-rsa-length n

This option adjusts the compliance mode "de-vs" for stricter key size requirements. For example, a value of 3000 turns rsa2048 and dsa2048 keys into non-VS-NfD compliant keys.


4.2.6 Doing things one usually doesn’t want to do

-n
--dry-run

Don’t make any changes (this is not completely implemented).

--list-only

Changes the behaviour of some commands. This is like --dry-run but different in some cases. The semantic of this option may be extended in the future. Currently it only skips the actual decryption pass and therefore enables a fast listing of the encryption keys.

-i
--interactive

Prompt before overwriting any files.

--debug-level level

Select the debug level for investigating problems. level may be a numeric value or by a keyword:

none

No debugging at all. A value of less than 1 may be used instead of the keyword.

basic

Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.

advanced

More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.

expert

Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.

guru

All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

--debug flags

Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice.

--debug-all

Set all useful debugging flags.

--debug-iolbf

Set stdout into line buffered mode. This option is only honored when given on the command line.

--debug-set-iobuf-size n

Change the buffer size of the IOBUFs to n kilobyte. Using 0 prints the current size. Note well: This is a maintainer only option and may thus be changed or removed at any time without notice.

--debug-allow-large-chunks

To facilitate software tests and experiments this option allows to specify a limit of up to 4 EiB (--chunk-size 62).

--faked-system-time epoch

This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsed since the year 1970. Alternatively epoch may be given as a full ISO time string (e.g. "20070924T154812").

If you suffix epoch with an exclamation mark (!), the system time will appear to be frozen at the specified time.

--full-timestrings

Change the format of printed creation and expiration times from just the date to the date and time. This is in general not useful and the same information is anyway available in --with-colons mode. These longer strings are also not well aligned with other printed data.

--enable-progress-filter

Enable certain PROGRESS status outputs. This option allows frontends to display a progress indicator while gpg is processing larger files. There is a slight performance overhead using it.

--status-fd n

Write special status strings to the file descriptor n. See the file DETAILS in the documentation for a listing of them.

--status-file file

Same as --status-fd, except the status data is written to file file.

--logger-fd n

Write log output to file descriptor n and not to STDERR.

--log-file file
--logger-file file

Same as --logger-fd, except the logger data is written to file file. Use socket:// to log to s socket.

--attribute-fd n

Write attribute subpackets to the file descriptor n. This is most useful for use with --status-fd, since the status messages are needed to separate out the various subpackets from the stream delivered to the file descriptor.

--attribute-file file

Same as --attribute-fd, except the attribute data is written to file file.

--comment string
--no-comments

Use string as a comment string in cleartext signatures and ASCII armored messages or keys (see --armor). The default behavior is not to use a comment string. --comment may be repeated multiple times to get multiple comment strings. --no-comments removes all comments. It is a good idea to keep the length of a single comment below 60 characters to avoid problems with mail programs wrapping such lines. Note that comment lines, like all other header lines, are not protected by the signature.

--emit-version
--no-emit-version

Force inclusion of the version string in ASCII armored output. If given once only the name of the program and the major number is emitted, given twice the minor is also emitted, given thrice the micro is added, and given four times an operating system identification is also emitted. --no-emit-version (default) disables the version line.

--sig-notation {name=value}
--cert-notation {name=value}
-N, --set-notation {name=value}

Put the name value pair into the signature as notation data. name must consist only of printable characters or spaces, and must contain a ’@’ character in the form keyname@domain.example.com (substituting the appropriate keyname and domain name, of course). This is to help prevent pollution of the IETF reserved notation namespace. The --expert flag overrides the ’@’ check. value may be any printable string; it will be encoded in UTF-8, so you should check that your --display-charset is set correctly. If you prefix name with an exclamation mark (!), the notation data will be flagged as critical (rfc4880:5.2.3.16). --sig-notation sets a notation for data signatures. --cert-notation sets a notation for key signatures (certifications). --set-notation sets both.

There are special codes that may be used in notation names. "%k" will be expanded into the key ID of the key being signed, "%K" into the long key ID of the key being signed, "%f" into the fingerprint of the key being signed, "%s" into the key ID of the key making the signature, "%S" into the long key ID of the key making the signature, "%g" into the fingerprint of the key making the signature (which might be a subkey), "%p" into the fingerprint of the primary key of the key making the signature, "%c" into the signature count from the OpenPGP smartcard, and "%%" results in a single "%". %k, %K, and %f are only meaningful when making a key signature (certification), and %c is only meaningful when using the OpenPGP smartcard.

--known-notation name

Adds name to a list of known critical signature notations. The effect of this is that gpg will not mark a signature with a critical signature notation of that name as bad. Note that gpg already knows by default about a few critical signatures notation names.

--sig-policy-url string
--cert-policy-url string
--set-policy-url string

Use string as a Policy URL for signatures (rfc4880:5.2.3.20). If you prefix it with an exclamation mark (!), the policy URL packet will be flagged as critical. --sig-policy-url sets a policy url for data signatures. --cert-policy-url sets a policy url for key signatures (certifications). --set-policy-url sets both.

The same %-expandos used for notation data are available here as well.

--sig-keyserver-url string

Use string as a preferred keyserver URL for data signatures. If you prefix it with an exclamation mark (!), the keyserver URL packet will be flagged as critical.

The same %-expandos used for notation data are available here as well.

--set-filename string

Use string as the filename which is stored inside messages. This overrides the default, which is to use the actual filename of the file being encrypted. Using the empty string for string effectively removes the filename from the output.

--for-your-eyes-only
--no-for-your-eyes-only

Set the ‘for your eyes only’ flag in the message. This causes GnuPG to refuse to save the file unless the --output option is given, and PGP to use a "secure viewer" with a claimed Tempest-resistant font to display the message. This option overrides --set-filename. --no-for-your-eyes-only disables this option.

--use-embedded-filename
--no-use-embedded-filename

Try to create a file with a name as embedded in the data. This can be a dangerous option as it enables overwriting files. Defaults to no. Note that the option --output overrides this option.

--cipher-algo name

Use name as cipher algorithm. Running the program with the command --version yields a list of supported algorithms. If this is not used the cipher algorithm is selected from the preferences stored with the key. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. The option --personal-cipher-preferences is the safe way to accomplish the same thing.

--aead-algo name

Specify that the AEAD algorithm name is to be used. This is useful for symmetric encryption where no key preference are available to select the AEAD algorithm. Running gpg with option --version shows the available AEAD algorithms. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. The option --personal-aead-preferences is the safe way to accomplish the same thing.

--digest-algo name

Use name as the message digest algorithm. Running the program with the command --version yields a list of supported algorithms. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. The option --personal-digest-preferences is the safe way to accomplish the same thing.

--compress-algo name

Use compression algorithm name. "zlib" is RFC-1950 ZLIB compression. "zip" is RFC-1951 ZIP compression which is used by PGP. "bzip2" is a more modern compression scheme that can compress some things better than zip or zlib, but at the cost of more memory used during compression and decompression. "uncompressed" or "none" disables compression. If this option is not used, the default behavior is to examine the recipient key preferences to see which algorithms the recipient supports. If all else fails, ZIP is used for maximum compatibility.

ZLIB may give better compression results than ZIP, as the compression window size is not limited to 8k. BZIP2 may give even better compression results than that, but will use a significantly larger amount of memory while compressing and decompressing. This may be significant in low memory situations. Note, however, that PGP (all versions) only supports ZIP compression. Using any algorithm other than ZIP or "none" will make the message unreadable with PGP. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. The option --personal-compress-preferences is the safe way to accomplish the same thing.

--cert-digest-algo name

Use name as the message digest algorithm used when signing a key. Running the program with the command --version yields a list of supported algorithms. Be aware that if you choose an algorithm that GnuPG supports but other OpenPGP implementations do not, then some users will not be able to use the key signatures you make, or quite possibly your entire key. Note also that a public key algorithm must be compatible with the specified digest algorithm; thus selecting an arbitrary digest algorithm may result in error messages from lower crypto layers or lead to security flaws.

--disable-cipher-algo name

Never allow the use of name as cipher algorithm. The given name will not be checked so that a later loaded algorithm will still get disabled.

--disable-pubkey-algo name

Never allow the use of name as public key algorithm. The given name will not be checked so that a later loaded algorithm will still get disabled.

--throw-keyids
--no-throw-keyids

Do not put the recipient key IDs into encrypted messages. This helps to hide the receivers of the message and is a limited countermeasure against traffic analysis.2 On the receiving side, it may slow down the decryption process because all available secret keys must be tried. --no-throw-keyids disables this option. This option is essentially the same as using --hidden-recipient for all recipients.

--not-dash-escaped

This option changes the behavior of cleartext signatures so that they can be used for patch files. You should not send such an armored file via email because all spaces and line endings are hashed too. You can not use this option for data which has 5 dashes at the beginning of a line, patch files don’t have this. A special armor header line tells GnuPG about this cleartext signature option.

--escape-from-lines
--no-escape-from-lines

Because some mailers change lines starting with "From " to ">From " it is good to handle such lines in a special way when creating cleartext signatures to prevent the mail system from breaking the signature. Note that all other PGP versions do it this way too. Enabled by default. --no-escape-from-lines disables this option.

--passphrase-repeat n

Specify how many times gpg will request a new passphrase be repeated. This is useful for helping memorize a passphrase. Defaults to 1 repetition; can be set to 0 to disable any passphrase repetition. Note that a n greater than 1 will pop up the pinentry window n+1 times even if a modern pinentry with two entry fields is used.

--passphrase-fd n

Read the passphrase from file descriptor n. Only the first line will be read from file descriptor n. If you use 0 for n, the passphrase will be read from STDIN. This can only be used if only one passphrase is supplied.

Note that since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--passphrase-file file

Read the passphrase from file file. Only the first line will be read from file file. This can only be used if only one passphrase is supplied. Obviously, a passphrase stored in a file is of questionable security if other users can read this file. Don’t use this option if you can avoid it.

Note that since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--passphrase string

Use string as the passphrase. This can only be used if only one passphrase is supplied. Obviously, this is of very questionable security on a multi-user system. Don’t use this option if you can avoid it.

Note that since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--pinentry-mode mode

Set the pinentry mode to mode. Allowed values for mode are:

default

Use the default of the agent, which is ask.

ask

Force the use of the Pinentry.

cancel

Emulate use of Pinentry’s cancel button.

error

Return a Pinentry error (“No Pinentry”).

loopback

Redirect Pinentry queries to the caller. Note that in contrast to Pinentry the user is not prompted again if he enters a bad password.

--no-symkey-cache

Disable the passphrase cache used for symmetrical en- and decryption. This cache is based on the message specific salt value (cf. --s2k-mode).

--request-origin origin

Tell gpg to assume that the operation ultimately originated at origin. Depending on the origin certain restrictions are applied and the Pinentry may include an extra note on the origin. Supported values for origin are: local which is the default, remote to indicate a remote origin or browser for an operation requested by a web browser.

--command-fd n

This is a replacement for the deprecated shared-memory IPC mode. If this option is enabled, user input on questions is not expected from the TTY but from the given file descriptor. It should be used together with --status-fd. See the file doc/DETAILS in the source distribution for details on how to use it.

--command-file file

Same as --command-fd, except the commands are read out of file file

--allow-non-selfsigned-uid
--no-allow-non-selfsigned-uid

Allow the import and use of keys with user IDs which are not self-signed. This is not recommended, as a non self-signed user ID is trivial to forge. --no-allow-non-selfsigned-uid disables.

--allow-freeform-uid

Disable all checks on the form of the user ID while generating a new one. This option should only be used in very special environments as it does not ensure the de-facto standard format of user IDs.

--ignore-time-conflict

GnuPG normally checks that the timestamps associated with keys and signatures have plausible values. However, sometimes a signature seems to be older than the key due to clock problems. This option makes these checks just a warning. See also --ignore-valid-from for timestamp issues on subkeys.

--ignore-valid-from

GnuPG normally does not select and use subkeys created in the future. This option allows the use of such keys and thus exhibits the pre-1.0.7 behaviour. You should not use this option unless there is some clock problem. See also --ignore-time-conflict for timestamp issues with signatures.

--ignore-crc-error

The ASCII armor used by OpenPGP is protected by a CRC checksum against transmission errors. Occasionally the CRC gets mangled somewhere on the transmission channel but the actual content (which is protected by the OpenPGP protocol anyway) is still okay. This option allows GnuPG to ignore CRC errors.

--ignore-mdc-error

This option changes a MDC integrity protection failure into a warning. It is required to decrypt old messages which did not use an MDC. It may also be useful if a message is partially garbled, but it is necessary to get as much data as possible out of that garbled message. Be aware that a missing or failed MDC can be an indication of an attack. Use with great caution; see also option --rfc2440.

--allow-old-cipher-algos

Old cipher algorithms like 3DES, IDEA, or CAST5 encrypt data using blocks of 64 bits; modern algorithms use blocks of 128 bit instead. To avoid certain attack on these old algorithms it is suggested not to encrypt more than 150 MiByte using the same key. For this reason gpg does not allow the use of 64 bit block size algorithms for encryption unless this option is specified.

--allow-weak-digest-algos

Signatures made with known-weak digest algorithms are normally rejected with an “invalid digest algorithm” message. This option allows the verification of signatures made with such weak algorithms. MD5 is the only digest algorithm considered weak by default. See also --weak-digest to reject other digest algorithms.

--weak-digest name

Treat the specified digest algorithm as weak. Signatures made over weak digests algorithms are normally rejected. This option can be supplied multiple times if multiple algorithms should be considered weak. See also --allow-weak-digest-algos to disable rejection of weak digests. MD5 is always considered weak, and does not need to be listed explicitly.

--allow-weak-key-signatures

To avoid a minor risk of collision attacks on third-party key signatures made using SHA-1, those key signatures are considered invalid. This options allows to override this restriction.

--override-compliance-check

The signature verification only allows the use of keys suitable in the current compliance mode. If the compliance mode has been forced by a global option, there might be no way to check certain signature. This option allows to override this and prints an extra warning in such a case. This option is ignored in –batch mode so that no accidental unattended verification may happen.

--no-default-keyring

Do not add the default keyring to the list of keyrings. Note that GnuPG needs for almost all operations a keyring. Thus if you use this option and do not provide alternate keyrings via --keyring, then GnuPG will still use the default keyring.

Note that if the option use-keyboxd is enabled in common.conf, no keyrings are used at all and keys are all maintained by the keyboxd process in its own database.

--no-keyring

Do not use any keyring at all. This overrides the default and all options which specify keyrings.

--skip-verify

Skip the signature verification step. This may be used to make the decryption faster if the signature verification is not needed.

--with-key-data

Print key listings delimited by colons (like --with-colons) and print the public key data.

--list-signatures
--list-sigs

Same as --list-keys, but the signatures are listed too. This command has the same effect as using --list-keys with --with-sig-list. Note that in contrast to --check-signatures the key signatures are not verified. This command can be used to create a list of signing keys missing in the local keyring; for example:

      gpg --list-sigs --with-colons USERID | \
        awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'
--fast-list-mode

Changes the output of the list commands to work faster; this is achieved by leaving some parts empty. Some applications don’t need the user ID and the trust information given in the listings. By using this options they can get a faster listing. The exact behaviour of this option may change in future versions. If you are missing some information, don’t use this option.

--no-literal

This is not for normal use. Use the source to see for what it might be useful.

--set-filesize

This is not for normal use. Use the source to see for what it might be useful.

--show-session-key

Display the session key used for one message. See --override-session-key for the counterpart of this option.

We think that Key Escrow is a Bad Thing; however the user should have the freedom to decide whether to go to prison or to reveal the content of one specific message without compromising all messages ever encrypted for one secret key.

You can also use this option if you receive an encrypted message which is abusive or offensive, to prove to the administrators of the messaging system that the ciphertext transmitted corresponds to an inappropriate plaintext so they can take action against the offending user.

--override-session-key string
--override-session-key-fd fd

Don’t use the public key but the session key string respective the session key taken from the first line read from file descriptor fd. The format of this string is the same as the one printed by --show-session-key. This option is normally not used but comes handy in case someone forces you to reveal the content of an encrypted message; using this option you can do this without handing out the secret key. Note that using --override-session-key may reveal the session key to all local users via the global process table. Often it is useful to combine this option with --no-keyring.

--ask-sig-expire
--no-ask-sig-expire

When making a data signature, prompt for an expiration time. If this option is not specified, the expiration time set via --default-sig-expire is used. --no-ask-sig-expire disables this option.

--default-sig-expire

The default expiration time to use for signature expiration. Valid values are "0" for no expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form YYYY-MM-DD. Defaults to "0".

--ask-cert-expire
--no-ask-cert-expire

When making a key signature, prompt for an expiration time. If this option is not specified, the expiration time set via --default-cert-expire is used. --no-ask-cert-expire disables this option.

--default-cert-expire

The default expiration time to use for key signature expiration. Valid values are "0" for no expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form YYYY-MM-DD. Defaults to "0".

--default-new-key-algo string

This option can be used to change the default algorithms for key generation. The string is similar to the arguments required for the command --quick-add-key but slightly different. For example the current default of "rsa2048/cert,sign+rsa2048/encr" (or "rsa3072") can be changed to the value of what we currently call future default, which is "ed25519/cert,sign+cv25519/encr". You need to consult the source code to learn the details. Note that the advanced key generation commands can always be used to specify a key algorithm directly.

--no-auto-trust-new-key

When creating a new key the ownertrust of the new key is set to ultimate. This option disables this and the user needs to manually assign an ownertrust value.

--force-sign-key

This option modifies the behaviour of the commands --quick-sign-key, --quick-lsign-key, and the "sign" sub-commands of --edit-key by forcing the creation of a key signature, even if one already exists.

--forbid-gen-key

This option is intended for use in the global config file to disallow the use of generate key commands. Those commands will then fail with the error code for Not Enabled.

--allow-secret-key-import

This is an obsolete option and is not used anywhere.

--allow-multiple-messages
--no-allow-multiple-messages

These are obsolete options; they have no more effect since GnuPG 2.2.8.

--enable-special-filenames

This option enables a mode in which filenames of the form -&n, where n is a non-negative decimal number, refer to the file descriptor n and not to a file with that name.

--no-expensive-trust-checks

Experimental use only.

--preserve-permissions

Don’t change the permissions of a secret keyring back to user read/write only. Use this option only if you really know what you are doing.

--default-preference-list string

Set the list of default preferences to string. This preference list is used for new keys and becomes the default for "setpref" in the --edit-key menu.

--default-keyserver-url name

Set the default keyserver URL to name. This keyserver will be used as the keyserver URL when writing a new self-signature on a key, which includes key generation and changing preferences.

--list-config

Display various internal configuration parameters of GnuPG. This option is intended for external programs that call GnuPG to perform tasks, and is thus not generally useful. See the file doc/DETAILS in the source distribution for the details of which configuration items may be listed. --list-config is only usable with --with-colons set.

--list-gcrypt-config

Display various internal configuration parameters of Libgcrypt.

--gpgconf-list

This command is similar to --list-config but in general only internally used by the gpgconf tool.

--gpgconf-test

This is more or less dummy action. However it parses the configuration file and returns with failure if the configuration file would prevent gpg from startup. Thus it may be used to run a syntax check on the configuration file.

--chuid uid

Change the current user to uid which may either be a number or a name. This can be used from the root account to run gpg for another user. If uid is not the current UID a standard PATH is set and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This option has only an effect when used on the command line. This option has currently no effect at all on Windows.


4.2.7 Deprecated options

--show-photos
--no-show-photos

Causes --list-keys, --list-signatures, --list-public-keys, --list-secret-keys, and verifying a signature to also display the photo ID attached to the key, if any. See also --photo-viewer. These options are deprecated. Use --list-options [no-]show-photos and/or --verify-options [no-]show-photos instead.

--show-keyring

Display the keyring name at the head of key listings to show which keyring a given key resides on. This option is deprecated: use --list-options [no-]show-keyring instead.

--always-trust

Identical to --trust-model always. This option is deprecated.

--show-notation
--no-show-notation

Show signature notations in the --list-signatures or --check-signatures listings as well as when verifying a signature with a notation in it. These options are deprecated. Use --list-options [no-]show-notation and/or --verify-options [no-]show-notation instead.

--show-policy-url
--no-show-policy-url

Show policy URLs in the --list-signatures or --check-signatures listings as well as when verifying a signature with a policy URL in it. These options are deprecated. Use --list-options [no-]show-policy-url and/or --verify-options [no-]show-policy-url instead.


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4.3 Configuration files

There are a few configuration files to control certain aspects of gpg’s operation. Unless noted, they are expected in the current home directory (see option --homedir).

gpg.conf

This is the standard configuration file read by gpg on startup. It may contain any valid long option; the leading two dashes may not be entered and the option may not be abbreviated. This default name may be changed on the command line (see gpg-option --options). You should backup this file.

common.conf

This is an optional configuration file read by gpg on startup. It may contain options pertaining to all components of GnuPG. Its current main use is for the "use-keyboxd" option.

Note that on larger installations, it is useful to put predefined files into the directory /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/skel/.gnupg so that newly created users start up with a working configuration. For existing users a small helper script is provided to create these files (see Create .gnupg home directories).

For internal purposes gpg creates and maintains a few other files; They all live in the current home directory (see option --homedir). Only the gpg program may modify these files.

~/.gnupg

This is the default home directory which is used if neither the environment variable GNUPGHOME nor the option --homedir is given.

~/.gnupg/pubring.gpg

The public keyring using a legacy format. You should backup this file.

If this file is not available, gpg defaults to the new keybox format and creates a file pubring.kbx unless that file already exists in which case that file will also be used for OpenPGP keys.

Note that in the case that both files, pubring.gpg and pubring.kbx exists but the latter has no OpenPGP keys, the legacy file pubring.gpg will be used. Take care: GnuPG versions before 2.1 will always use the file pubring.gpg because they do not know about the new keybox format. In the case that you have to use GnuPG 1.4 to decrypt archived data you should keep this file.

~/.gnupg/pubring.gpg.lock

The lock file for the public keyring.

~/.gnupg/pubring.kbx

The public keyring using the new keybox format. This file is shared with gpgsm. You should backup this file. See above for the relation between this file and it predecessor.

To convert an existing pubring.gpg file to the keybox format, you first backup the ownertrust values, then rename pubring.gpg to publickeys.backup, so it won’t be recognized by any GnuPG version, run import, and finally restore the ownertrust values:

  $ cd ~/.gnupg
  $ gpg --export-ownertrust >otrust.lst
  $ mv pubring.gpg publickeys.backup
  $ gpg --import-options restore --import publickeys.backups
  $ gpg --import-ownertrust otrust.lst
  
~/.gnupg/pubring.kbx.lock

The lock file for pubring.kbx.

~/.gnupg/secring.gpg

The legacy secret keyring as used by GnuPG versions before 2.1. It is not used by GnuPG 2.1 and later. You may want to keep it in case you have to use GnuPG 1.4 to decrypt archived data.

~/.gnupg/secring.gpg.lock

The lock file for the legacy secret keyring.

~/.gnupg/.gpg-v21-migrated

File indicating that a migration to GnuPG 2.1 has been done.

~/.gnupg/trustdb.gpg

The trust database. There is no need to backup this file; it is better to backup the ownertrust values (see option --export-ownertrust).

~/.gnupg/trustdb.gpg.lock

The lock file for the trust database.

~/.gnupg/random_seed

A file used to preserve the state of the internal random pool.

~/.gnupg/openpgp-revocs.d/

This is the directory where gpg stores pre-generated revocation certificates. The file name corresponds to the OpenPGP fingerprint of the respective key. It is suggested to backup those certificates and if the primary private key is not stored on the disk to move them to an external storage device. Anyone who can access these files is able to revoke the corresponding key. You may want to print them out. You should backup all files in this directory and take care to keep this backup closed away.

Operation is further controlled by a few environment variables:

HOME

Used to locate the default home directory.

GNUPGHOME

If set directory used instead of "~/.gnupg".

GPG_AGENT_INFO

This variable is obsolete; it was used by GnuPG versions before 2.1.

PINENTRY_USER_DATA

This value is passed via gpg-agent to pinentry. It is useful to convey extra information to a custom pinentry.

COLUMNS
LINES

Used to size some displays to the full size of the screen.

LANGUAGE

Apart from its use by GNU, it is used in the W32 version to override the language selection done through the Registry. If used and set to a valid and available language name (langid), the file with the translation is loaded from gpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory out of which the gpg binary has been loaded. If it can’t be loaded the Registry is tried and as last resort the native Windows locale system is used.

GNUPG_BUILD_ROOT

This variable is only used by the regression test suite as a helper under operating systems without proper support to figure out the name of a process’ text file.

When calling the gpg-agent component gpg sends a set of environment variables to gpg-agent. The names of these variables can be listed using the command:

  gpg-connect-agent 'getinfo std_env_names' /bye | awk '$1=="D" {print $2}'

4.4 Examples

gpg -se -r Bob file

sign and encrypt for user Bob

gpg –clear-sign file

make a cleartext signature

gpg -sb file

make a detached signature

gpg -u 0x12345678 -sb file

make a detached signature with the key 0x12345678

gpg –list-keys user_ID

show keys

gpg –fingerprint user_ID

show fingerprint

gpg –verify pgpfile
gpg –verify sigfile [datafile]

Verify the signature of the file but do not output the data unless requested. The second form is used for detached signatures, where sigfile is the detached signature (either ASCII armored or binary) and datafile are the signed data; if this is not given, the name of the file holding the signed data is constructed by cutting off the extension (".asc" or ".sig") of sigfile or by asking the user for the filename. If the option --output is also used the signed data is written to the file specified by that option; use - to write the signed data to stdout.

FILTER EXPRESSIONS

The options --import-filter and --export-filter use expressions with this syntax (square brackets indicate an optional part and curly braces a repetition, white space between the elements are allowed):

  [lc] {[{flag}] PROPNAME op VALUE [lc]}

The name of a property (PROPNAME) may only consist of letters, digits and underscores. The description for the filter type describes which properties are defined. If an undefined property is used it evaluates to the empty string. Unless otherwise noted, the VALUE must always be given and may not be the empty string. No quoting is defined for the value, thus the value may not contain the strings && or ||, which are used as logical connection operators. The flag -- can be used to remove this restriction.

Numerical values are computed as long int; standard C notation applies. lc is the logical connection operator; either && for a conjunction or || for a disjunction. A conjunction is assumed at the begin of an expression. Conjunctions have higher precedence than disjunctions. If VALUE starts with one of the characters used in any op a space after the op is required.

The supported operators (op) are:

=~

Substring must match.

!~

Substring must not match.

=

The full string must match.

<>

The full string must not match.

==

The numerical value must match.

!=

The numerical value must not match.

<=

The numerical value of the field must be LE than the value.

<

The numerical value of the field must be LT than the value.

>

The numerical value of the field must be GT than the value.

>=

The numerical value of the field must be GE than the value.

-le

The string value of the field must be less or equal than the value.

-lt

The string value of the field must be less than the value.

-gt

The string value of the field must be greater than the value.

-ge

The string value of the field must be greater or equal than the value.

-n

True if value is not empty (no value allowed).

-z

True if value is empty (no value allowed).

-t

Alias for "PROPNAME != 0" (no value allowed).

-f

Alias for "PROPNAME == 0" (no value allowed).

Values for flag must be space separated. The supported flags are:

VALUE spans to the end of the expression.

-c

The string match in this part is done case-sensitive.

-t

Leading and trailing spaces are not removed from VALUE. The optional single space after op is here required.

The filter options concatenate several specifications for a filter of the same type. For example the four options in this example:

 --import-filter keep-uid="uid =~ Alfa"
 --import-filter keep-uid="&& uid !~ Test"
 --import-filter keep-uid="|| uid =~ Alpha"
 --import-filter keep-uid="uid !~ Test"

which is equivalent to

 --import-filter \
  keep-uid="uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"

imports only the user ids of a key containing the strings "Alfa" or "Alpha" but not the string "test".

RETURN VALUE

The program returns 0 if there are no severe errors, 1 if at least a signature was bad, and other error codes for fatal errors.

Note that signature verification requires exact knowledge of what has been signed and by whom it has been signed. Using only the return code is thus not an appropriate way to verify a signature by a script. Either make proper use or the status codes or use the gpgv tool which has been designed to make signature verification easy for scripts.

WARNINGS

Use a good password for your user account and make sure that all security issues are always fixed on your machine. Also employ diligent physical protection to your machine. Consider to use a good passphrase as a last resort protection to your secret key in the case your machine gets stolen. It is important that your secret key is never leaked. Using an easy to carry around token or smartcard with the secret key is often a advisable.

If you are going to verify detached signatures, make sure that the program knows about it; either give both filenames on the command line or use ‘-’ to specify STDIN.

For scripted or other unattended use of gpg make sure to use the machine-parseable interface and not the default interface which is intended for direct use by humans. The machine-parseable interface provides a stable and well documented API independent of the locale or future changes of gpg. To enable this interface use the options --with-colons and --status-fd. For certain operations the option --command-fd may come handy too. See this man page and the file DETAILS for the specification of the interface. Note that the GnuPG “info” pages as well as the PDF version of the GnuPG manual features a chapter on unattended use of GnuPG. As an alternative the library GPGME can be used as a high-level abstraction on top of that interface.

INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS

GnuPG tries to be a very flexible implementation of the OpenPGP standard. In particular, GnuPG implements many of the optional parts of the standard, such as the SHA-512 hash, and the ZLIB and BZIP2 compression algorithms. It is important to be aware that not all OpenPGP programs implement these optional algorithms and that by forcing their use via the --cipher-algo, --digest-algo, --cert-digest-algo, or --compress-algo options in GnuPG, it is possible to create a perfectly valid OpenPGP message, but one that cannot be read by the intended recipient.

There are dozens of variations of OpenPGP programs available, and each supports a slightly different subset of these optional algorithms. For example, until recently, no (unhacked) version of PGP supported the BLOWFISH cipher algorithm. A message using BLOWFISH simply could not be read by a PGP user. By default, GnuPG uses the standard OpenPGP preferences system that will always do the right thing and create messages that are usable by all recipients, regardless of which OpenPGP program they use. Only override this safe default if you really know what you are doing.

If you absolutely must override the safe default, or if the preferences on a given key are invalid for some reason, you are far better off using the --pgp6, --pgp7, or --pgp8 options. These options are safe as they do not force any particular algorithms in violation of OpenPGP, but rather reduce the available algorithms to a "PGP-safe" list.

BUGS

On older systems this program should be installed as setuid(root). This is necessary to lock memory pages. Locking memory pages prevents the operating system from writing memory pages (which may contain passphrases or other sensitive material) to disk. If you get no warning message about insecure memory your operating system supports locking without being root. The program drops root privileges as soon as locked memory is allocated.

Note also that some systems (especially laptops) have the ability to “suspend to disk” (also known as “safe sleep” or “hibernate”). This writes all memory to disk before going into a low power or even powered off mode. Unless measures are taken in the operating system to protect the saved memory, passphrases or other sensitive material may be recoverable from it later.

Before you report a bug you should first search the mailing list archives for similar problems and second check whether such a bug has already been reported to our bug tracker at https://bugs.gnupg.org.


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4.5 Unattended Usage

gpg is often used as a backend engine by other software. To help with this a machine interface has been defined to have an unambiguous way to do this. The options --status-fd and --batch are almost always required for this.


4.5.1 Programmatic use of GnuPG

Please consider using GPGME instead of calling gpg directly. GPGME offers a stable, backend-independent interface for many cryptographic operations. It supports OpenPGP and S/MIME, and also allows interaction with various GnuPG components.

GPGME provides a C-API, and comes with bindings for C++, Qt, and Python. Bindings for other languages are available.


4.5.2 Ephemeral home directories

Sometimes you want to contain effects of some operation, for example you want to import a key to inspect it, but you do not want this key to be added to your keyring. In earlier versions of GnuPG, it was possible to specify alternate keyring files for both public and secret keys. In modern GnuPG versions, however, we changed how secret keys are stored in order to better protect secret key material, and it was not possible to preserve this interface.

The preferred way to do this is to use ephemeral home directories. This technique works across all versions of GnuPG.

Create a temporary directory, create (or copy) a configuration that meets your needs, make gpg use this directory either using the environment variable GNUPGHOME, or the option --homedir. GPGME supports this too on a per-context basis, by modifying the engine info of contexts. Now execute whatever operation you like, import and export key material as necessary. Once finished, you can delete the directory. All GnuPG backend services that were started will detect this and shut down.


4.5.3 The quick key manipulation interface

Recent versions of GnuPG have an interface to manipulate keys without using the interactive command --edit-key. This interface was added mainly for the benefit of GPGME (please consider using GPGME, see the manual subsection “Programmatic use of GnuPG”). This interface is described in the subsection “How to manage your keys”.


4.5.4 Unattended key generation

The command --generate-key may be used along with the option --batch for unattended key generation. This is the most flexible way of generating keys, but it is also the most complex one. Consider using the quick key manipulation interface described in the previous subsection “The quick key manipulation interface”.

The parameters for the key are either read from stdin or given as a file on the command line. The format of the parameter file is as follows:

  • Text only, line length is limited to about 1000 characters.
  • UTF-8 encoding must be used to specify non-ASCII characters.
  • Empty lines are ignored.
  • Leading and trailing white space is ignored.
  • A hash sign as the first non white space character indicates a comment line.
  • Control statements are indicated by a leading percent sign, the arguments are separated by white space from the keyword.
  • Parameters are specified by a keyword, followed by a colon. Arguments are separated by white space.
  • The first parameter must be ‘Key-Type’; control statements may be placed anywhere.
  • The order of the parameters does not matter except for ‘Key-Type’ which must be the first parameter. The parameters are only used for the generated keyblock (primary and subkeys); parameters from previous sets are not used. Some syntactically checks may be performed.
  • Key generation takes place when either the end of the parameter file is reached, the next ‘Key-Type’ parameter is encountered or at the control statement ‘%commit’ is encountered.

Control statements:

%echo text

Print text as diagnostic.

%dry-run

Suppress actual key generation (useful for syntax checking).

%commit

Perform the key generation. Note that an implicit commit is done at the next Key-Type parameter.

%pubring filename

Do not write the key to the default or commandline given keyring but to filename. This must be given before the first commit to take place, duplicate specification of the same filename is ignored, the last filename before a commit is used. The filename is used until a new filename is used (at commit points) and all keys are written to that file. If a new filename is given, this file is created (and overwrites an existing one).

See the previous subsection “Ephemeral home directories” for a more robust way to contain side-effects.

%secring filename

This option is a no-op for GnuPG 2.1 and later.

See the previous subsection “Ephemeral home directories”.

%ask-passphrase
%no-ask-passphrase

This option is a no-op for GnuPG 2.1 and later.

%no-protection

Using this option allows the creation of keys without any passphrase protection. This option is mainly intended for regression tests.

%transient-key

If given the keys are created using a faster and a somewhat less secure random number generator. This option may be used for keys which are only used for a short time and do not require full cryptographic strength. It takes only effect if used together with the control statement ‘%no-protection’.

General Parameters:

Key-Type: algo

Starts a new parameter block by giving the type of the primary key. The algorithm must be capable of signing. This is a required parameter. algo may either be an OpenPGP algorithm number or a string with the algorithm name. The special value ‘default’ may be used for algo to create the default key type; in this case a ‘Key-Usage’ shall not be given and ‘default’ also be used for ‘Subkey-Type’.

Key-Length: nbits

The requested length of the generated key in bits. The default is returned by running the command ‘gpg --gpgconf-list’. For ECC keys this parameter is ignored.

Key-Curve: curve

The requested elliptic curve of the generated key. This is a required parameter for ECC keys. It is ignored for non-ECC keys.

Key-Grip: hexstring

This is optional and used to generate a CSR or certificate for an already existing key. Key-Length will be ignored when given.

Key-Usage: usage-list

Space or comma delimited list of key usages. Allowed values are ‘encrypt’, ‘sign’, and ‘auth’. This is used to generate the key flags. Please make sure that the algorithm is capable of this usage. Note that OpenPGP requires that all primary keys are capable of certification, so no matter what usage is given here, the ‘cert’ flag will be on. If no ‘Key-Usage’ is specified and the ‘Key-Type’ is not ‘default’, all allowed usages for that particular algorithm are used; if it is not given but ‘default’ is used the usage will be ‘sign’.

Subkey-Type: algo

This generates a secondary key (subkey). Currently only one subkey can be handled. See also ‘Key-Type’ above.

Subkey-Length: nbits

Length of the secondary key (subkey) in bits. The default is returned by running the command ‘gpg --gpgconf-list’.

Subkey-Curve: curve

Key curve for a subkey; similar to ‘Key-Curve’.

Subkey-Usage: usage-list

Key usage lists for a subkey; similar to ‘Key-Usage’.

Passphrase: string

If you want to specify a passphrase for the secret key, enter it here. Default is to use the Pinentry dialog to ask for a passphrase.

Name-Real: name
Name-Comment: comment
Name-Email: email

The three parts of a user name. Remember to use UTF-8 encoding here. If you don’t give any of them, no user ID is created.

Expire-Date: iso-date|(number[d|w|m|y])

Set the expiration date for the key (and the subkey). It may either be entered in ISO date format (e.g. "20000815T145012") or as number of days, weeks, month or years after the creation date. The special notation "seconds=N" is also allowed to specify a number of seconds since creation. Without a letter days are assumed. Note that there is no check done on the overflow of the type used by OpenPGP for timestamps. Thus you better make sure that the given value make sense. Although OpenPGP works with time intervals, GnuPG uses an absolute value internally and thus the last year we can represent is 2105.

Creation-Date: iso-date

Set the creation date of the key as stored in the key information and which is also part of the fingerprint calculation. Either a date like "1986-04-26" or a full timestamp like "19860426T042640" may be used. The time is considered to be UTC. The special notation "seconds=N" may be used to directly specify a the number of seconds since Epoch (Unix time). If it is not given the current time is used.

Preferences: string

Set the cipher, hash, and compression preference values for this key. This expects the same type of string as the sub-command ‘setpref’ in the --edit-key menu.

Revoker: algo:fpr [sensitive]

Add a designated revoker to the generated key. Algo is the public key algorithm of the designated revoker (i.e. RSA=1, DSA=17, etc.) fpr is the fingerprint of the designated revoker. The optional ‘sensitive’ flag marks the designated revoker as sensitive information. Only v4 keys may be designated revokers.

Keyserver: string

This is an optional parameter that specifies the preferred keyserver URL for the key.

Handle: string

This is an optional parameter only used with the status lines KEY_CREATED and KEY_NOT_CREATED. string may be up to 100 characters and should not contain spaces. It is useful for batch key generation to associate a key parameter block with a status line.

Here is an example on how to create a key in an ephemeral home directory:

$ export GNUPGHOME="$(mktemp -d)"
$ cat >foo <<EOF
     %echo Generating a basic OpenPGP key
     Key-Type: DSA
     Key-Length: 1024
     Subkey-Type: ELG-E
     Subkey-Length: 1024
     Name-Real: Joe Tester
     Name-Comment: with stupid passphrase
     Name-Email: joe@foo.bar
     Expire-Date: 0
     Passphrase: abc
     # Do a commit here, so that we can later print "done" :-)
     %commit
     %echo done
EOF
$ gpg --batch --generate-key foo
 [...]
$ gpg --list-secret-keys
/tmp/tmp.0NQxB74PEf/pubring.kbx
-------------------------------
sec   dsa1024 2016-12-16 [SCA]
      768E895903FC1C44045C8CB95EEBDB71E9E849D0
uid           [ultimate] Joe Tester (with stupid passphrase) <joe@foo.bar>
ssb   elg1024 2016-12-16 [E]

If you want to create a key with the default algorithms you would use these parameters:

     %echo Generating a default key
     Key-Type: default
     Subkey-Type: default
     Name-Real: Joe Tester
     Name-Comment: with stupid passphrase
     Name-Email: joe@foo.bar
     Expire-Date: 0
     Passphrase: abc
     # Do a commit here, so that we can later print "done" :-)
     %commit
     %echo done

5 Invoking GPGSM

gpgsm is a tool similar to gpg to provide digital encryption and signing services on X.509 certificates and the CMS protocol. It is mainly used as a backend for S/MIME mail processing. gpgsm includes a full featured certificate management and complies with all rules defined for the German Sphinx project.

See Option Index, for an index to GPGSM’s commands and options.


5.1 Commands

Commands are not distinguished from options except for the fact that only one command is allowed.


5.1.1 Commands not specific to the function

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help, -h

Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command.

--warranty

Print warranty information. Note that you cannot abbreviate this command.

--dump-options

Print a list of all available options and commands. Note that you cannot abbreviate this command.


5.1.2 Commands to select the type of operation

--encrypt

Perform an encryption. The keys the data is encrypted to must be set using the option --recipient.

--decrypt

Perform a decryption; the type of input is automatically determined. It may either be in binary form or PEM encoded; automatic determination of base-64 encoding is not done.

--sign

Create a digital signature. The key used is either the fist one found in the keybox or those set with the --local-user option.

--verify

Check a signature file for validity. Depending on the arguments a detached signature may also be checked.

--server

Run in server mode and wait for commands on the stdin.

--call-dirmngr command [args]

Behave as a Dirmngr client issuing the request command with the optional list of args. The output of the Dirmngr is printed stdout. Please note that file names given as arguments should have an absolute file name (i.e. commencing with /) because they are passed verbatim to the Dirmngr and the working directory of the Dirmngr might not be the same as the one of this client. Currently it is not possible to pass data via stdin to the Dirmngr. command should not contain spaces.

This is command is required for certain maintaining tasks of the dirmngr where a dirmngr must be able to call back to gpgsm. See the Dirmngr manual for details.

--call-protect-tool arguments

Certain maintenance operations are done by an external program call gpg-protect-tool; this is usually not installed in a directory listed in the PATH variable. This command provides a simple wrapper to access this tool. arguments are passed verbatim to this command; use ‘--help’ to get a list of supported operations.


5.1.3 How to manage the certificates and keys

--generate-key
--gen-key

This command allows the creation of a certificate signing request or a self-signed certificate. It is commonly used along with the --output option to save the created CSR or certificate into a file. If used with the --batch a parameter file is used to create the CSR or certificate and it is further possible to create non-self-signed certificates.

--list-keys
-k

List all available certificates stored in the local key database. Note that the displayed data might be reformatted for better human readability and illegal characters are replaced by safe substitutes.

--list-secret-keys
-K

List all available certificates for which a corresponding a secret key is available.

--list-external-keys pattern

List certificates matching pattern using an external server. This utilizes the dirmngr service.

--list-chain

Same as --list-keys but also prints all keys making up the chain.

--dump-cert
--dump-keys

List all available certificates stored in the local key database using a format useful mainly for debugging.

--dump-chain

Same as --dump-keys but also prints all keys making up the chain.

--dump-secret-keys

List all available certificates for which a corresponding a secret key is available using a format useful mainly for debugging.

--dump-external-keys pattern

List certificates matching pattern using an external server. This utilizes the dirmngr service. It uses a format useful mainly for debugging.

--show-certs [files]

This command takes certificate files as input and prints information about them in the same format as --dump-cert does. Each file may either contain a single binary certificate or several PEM encoded certificates. If no files are given, the input is taken from stdin.

Please note that the listing format may be changed in future releases and that the option --with-colons has currently no effect.

--keydb-clear-some-cert-flags

This is a debugging aid to reset certain flags in the key database which are used to cache certain certificate statuses. It is especially useful if a bad CRL or a weird running OCSP responder did accidentally revoke certificate. There is no security issue with this command because gpgsm always make sure that the validity of a certificate is checked right before it is used.

--delete-keys pattern

Delete the keys matching pattern. Note that there is no command to delete the secret part of the key directly. In case you need to do this, you should run the command gpgsm --dump-secret-keys KEYID before you delete the key, copy the string of hex-digits in the “keygrip” line and delete the file consisting of these hex-digits and the suffix .key from the private-keys-v1.d directory below our GnuPG home directory (usually ~/.gnupg).

--export [pattern]

Export all certificates stored in the Keybox or those specified by the optional pattern. Those pattern consist of a list of user ids (see how-to-specify-a-user-id). When used along with the --armor option a few informational lines are prepended before each block. There is one limitation: As there is no commonly agreed upon way to pack more than one certificate into an ASN.1 structure, the binary export (i.e. without using armor) works only for the export of one certificate. Thus it is required to specify a pattern which yields exactly one certificate. Ephemeral certificate are only exported if all pattern are given as fingerprints or keygrips.

--export-secret-key-p12 key-id

Export the private key and the certificate identified by key-id using the PKCS#12 format. When used with the --armor option a few informational lines are prepended to the output. Note, that the PKCS#12 format is not very secure and proper transport security should be used to convey the exported key. (See option --p12-charset.)

--export-secret-key-p8 key-id
--export-secret-key-raw key-id

Export the private key of the certificate identified by key-id with any encryption stripped. The ...-raw command exports in PKCS#1 format; the ...-p8 command exports in PKCS#8 format. When used with the --armor option a few informational lines are prepended to the output. These commands are useful to prepare a key for use on a TLS server.

--import [files]

Import the certificates from the PEM or binary encoded files as well as from signed-only messages. This command may also be used to import a secret key from a PKCS#12 file.

--learn-card

Read information about the private keys from the smartcard and import the certificates from there. This command utilizes the gpg-agent and in turn the scdaemon.

--change-passphrase user_id
--passwd user_id

Change the passphrase of the private key belonging to the certificate specified as user_id. Note, that changing the passphrase/PIN of a smartcard is not yet supported.


5.2 Option Summary

GPGSM features a bunch of options to control the exact behaviour and to change the default configuration.


5.2.1 How to change the configuration

These options are used to change the configuration and are usually found in the option file.

--options file

Reads configuration from file instead of from the default per-user configuration file. The default configuration file is named gpgsm.conf and expected in the .gnupg directory directly below the home directory of the user.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

-v
--verbose

Outputs additional information while running. You can increase the verbosity by giving several verbose commands to gpgsm, such as ‘-vv’.

--ldapserver string
--keyserver string

Add an LDAP server to use for X.509 certificate and CRL lookup. This option can be given multiple times to configure more than one LDAP server. Note that in general dirmngr should be configured with the list of LDAP servers; if this option is also configured here, it is used in addition to those configured in dirmngr. For the syntax see the description of dirmngr’s ldapserver option.

--policy-file filename

Change the default name of the policy file to filename. The default name is policies.txt.

--agent-program file

Specify an agent program to be used for secret key operations. The default value is determined by running the command gpgconf. Note that the pipe symbol (|) is used for a regression test suite hack and may thus not be used in the file name.

--dirmngr-program file

Specify a dirmngr program to be used for CRL checks. The default value is /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/bin/dirmngr.

--prefer-system-dirmngr

This option is obsolete and ignored.

--disable-dirmngr

Entirely disable the use of the Dirmngr.

--no-autostart

Do not start the gpg-agent or the dirmngr if it has not yet been started and its service is required. This option is mostly useful on machines where the connection to gpg-agent has been redirected to another machines. If dirmngr is required on the remote machine, it may be started manually using gpgconf --launch dirmngr.

--no-secmem-warning

Do not print a warning when the so called "secure memory" cannot be used.

--log-file file

When running in server mode, append all logging output to file. Use socket:// to log to socket.


5.2.2 Certificate related options

--enable-policy-checks
--disable-policy-checks

By default policy checks are enabled. These options may be used to change it.

--enable-crl-checks
--disable-crl-checks

By default the CRL checks are enabled and the DirMngr is used to check for revoked certificates. The disable option is most useful with an off-line network connection to suppress this check and also to avoid that new certificates introduce a web bug by including a certificate specific CRL DP. The disable option also disables an issuer certificate lookup via the authorityInfoAccess property of the certificate; the --enable-issuer-key-retrieve can be used to make use of that property anyway.

--enable-trusted-cert-crl-check
--disable-trusted-cert-crl-check

By default the CRL for trusted root certificates are checked like for any other certificates. This allows a CA to revoke its own certificates voluntary without the need of putting all ever issued certificates into a CRL. The disable option may be used to switch this extra check off. Due to the caching done by the Dirmngr, there will not be any noticeable performance gain. Note, that this also disables possible OCSP checks for trusted root certificates. A more specific way of disabling this check is by adding the “relax” keyword to the root CA line of the trustlist.txt

--force-crl-refresh

Tell the dirmngr to reload the CRL for each request. For better performance, the dirmngr will actually optimize this by suppressing the loading for short time intervals (e.g. 30 minutes). This option is useful to make sure that a fresh CRL is available for certificates hold in the keybox. The suggested way of doing this is by using it along with the option --with-validation for a key listing command. This option should not be used in a configuration file.

--enable-issuer-based-crl-check

Run a CRL check even for certificates which do not have any CRL distribution point. This requires that a suitable LDAP server has been configured in Dirmngr and that the CRL can be found using the issuer. This option reverts to what GnuPG did up to version 2.2.20. This option is in general not useful.

--enable-ocsp
--disable-ocsp

By default OCSP checks are disabled. The enable option may be used to enable OCSP checks via Dirmngr. If CRL checks are also enabled, CRLs will be used as a fallback if for some reason an OCSP request will not succeed. Note, that you have to allow OCSP requests in Dirmngr’s configuration too (option --allow-ocsp) and configure Dirmngr properly. If you do not do so you will get the error code ‘Not supported’.

--auto-issuer-key-retrieve

If a required certificate is missing while validating the chain of certificates, try to load that certificate from an external location. This usually means that Dirmngr is employed to search for the certificate. Note that this option makes a "web bug" like behavior possible. LDAP server operators can see which keys you request, so by sending you a message signed by a brand new key (which you naturally will not have on your local keybox), the operator can tell both your IP address and the time when you verified the signature.

--validation-model name

This option changes the default validation model. The only possible values are "shell" (which is the default), "chain" which forces the use of the chain model and "steed" for a new simplified model. The chain model is also used if an option in the trustlist.txt or an attribute of the certificate requests it. However the standard model (shell) is in that case always tried first.

--ignore-cert-extension oid

Add oid to the list of ignored certificate extensions. The oid is expected to be in dotted decimal form, like 2.5.29.3. This option may be used more than once. Critical flagged certificate extensions matching one of the OIDs in the list are treated as if they are actually handled and thus the certificate will not be rejected due to an unknown critical extension. Use this option with care because extensions are usually flagged as critical for a reason.


5.2.3 Input and Output

--armor
-a

Create PEM encoded output. Default is binary output.

--base64

Create Base-64 encoded output; i.e. PEM without the header lines.

--assume-armor

Assume the input data is PEM encoded. Default is to autodetect the encoding but this is may fail.

--assume-base64

Assume the input data is plain base-64 encoded.

--assume-binary

Assume the input data is binary encoded.

--p12-charset name

gpgsm uses the UTF-8 encoding when encoding passphrases for PKCS#12 files. This option may be used to force the passphrase to be encoded in the specified encoding name. This is useful if the application used to import the key uses a different encoding and thus will not be able to import a file generated by gpgsm. Commonly used values for name are Latin1 and CP850. Note that gpgsm itself automagically imports any file with a passphrase encoded to the most commonly used encodings.

--default-key user_id

Use user_id as the standard key for signing. This key is used if no other key has been defined as a signing key. Note, that the first --local-users option also sets this key if it has not yet been set; however --default-key always overrides this.

--local-user user_id
-u user_id

Set the user(s) to be used for signing. The default is the first secret key found in the database.

--recipient name
-r

Encrypt to the user id name. There are several ways a user id may be given (see how-to-specify-a-user-id).

--output file
-o file

Write output to file. The default is to write it to stdout.

--with-key-data

Displays extra information with the --list-keys commands. Especially a line tagged grp is printed which tells you the keygrip of a key. This string is for example used as the file name of the secret key. Implies --with-colons.

--with-validation

When doing a key listing, do a full validation check for each key and print the result. This is usually a slow operation because it requires a CRL lookup and other operations.

When used along with --import, a validation of the certificate to import is done and only imported if it succeeds the test. Note that this does not affect an already available certificate in the DB. This option is therefore useful to simply verify a certificate.

--with-md5-fingerprint

For standard key listings, also print the MD5 fingerprint of the certificate.

--with-keygrip

Include the keygrip in standard key listings. Note that the keygrip is always listed in --with-colons mode.

--with-secret

Include info about the presence of a secret key in public key listings done with --with-colons.


5.2.4 How to change how the CMS is created

--include-certs n

Using n of -2 includes all certificate except for the root cert, -1 includes all certs, 0 does not include any certs, 1 includes only the signers cert and all other positive values include up to n certificates starting with the signer cert. The default is -2.

--cipher-algo oid

Use the cipher algorithm with the ASN.1 object identifier oid for encryption. For convenience the strings 3DES, AES and AES256 may be used instead of their OIDs. The default is AES (2.16.840.1.101.3.4.1.2).

--digest-algo name

Use name as the message digest algorithm. Usually this algorithm is deduced from the respective signing certificate. This option forces the use of the given algorithm and may lead to severe interoperability problems.


5.2.5 Doing things one usually do not want to do

--chuid uid

Change the current user to uid which may either be a number or a name. This can be used from the root account to run gpgsm for another user. If uid is not the current UID a standard PATH is set and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This option has only an effect when used on the command line. This option has currently no effect at all on Windows.

--extra-digest-algo name

Sometimes signatures are broken in that they announce a different digest algorithm than actually used. gpgsm uses a one-pass data processing model and thus needs to rely on the announced digest algorithms to properly hash the data. As a workaround this option may be used to tell gpgsm to also hash the data using the algorithm name; this slows processing down a little bit but allows verification of such broken signatures. If gpgsm prints an error like “digest algo 8 has not been enabled” you may want to try this option, with ‘SHA256’ for name.

--compliance string

Set the compliance mode. Valid values are shown when using "help" for string.

--min-rsa-length n

This option adjusts the compliance mode "de-vs" for stricter key size requirements. For example, a value of 3000 turns rsa2048 and dsa2048 keys into non-VS-NfD compliant keys.

--faked-system-time epoch

This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsed since the year 1970. Alternatively epoch may be given as a full ISO time string (e.g. "20070924T154812").

--with-ephemeral-keys

Include ephemeral flagged keys in the output of key listings. Note that they are included anyway if the key specification for a listing is given as fingerprint or keygrip.

--debug-level level

Select the debug level for investigating problems. level may be a numeric value or by a keyword:

none

No debugging at all. A value of less than 1 may be used instead of the keyword.

basic

Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.

advanced

More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.

expert

Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.

guru

All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

--debug flags

Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice.

Note, that all flags set using this option may get overridden by --debug-level.

--debug-all

Same as --debug=0xffffffff

--debug-allow-core-dump

Usually gpgsm tries to avoid dumping core by well written code and by disabling core dumps for security reasons. However, bugs are pretty durable beasts and to squash them it is sometimes useful to have a core dump. This option enables core dumps unless the Bad Thing happened before the option parsing.

--debug-no-chain-validation

This is actually not a debugging option but only useful as such. It lets gpgsm bypass all certificate chain validation checks.

--debug-ignore-expiration

This is actually not a debugging option but only useful as such. It lets gpgsm ignore all notAfter dates, this is used by the regression tests.

--passphrase-fd n

Read the passphrase from file descriptor n. Only the first line will be read from file descriptor n. If you use 0 for n, the passphrase will be read from STDIN. This can only be used if only one passphrase is supplied.

Note that this passphrase is only used if the option --batch has also been given.

--pinentry-mode mode

Set the pinentry mode to mode. Allowed values for mode are:

default

Use the default of the agent, which is ask.

ask

Force the use of the Pinentry.

cancel

Emulate use of Pinentry’s cancel button.

error

Return a Pinentry error (“No Pinentry”).

loopback

Redirect Pinentry queries to the caller. Note that in contrast to Pinentry the user is not prompted again if he enters a bad password.

--request-origin origin

Tell gpgsm to assume that the operation ultimately originated at origin. Depending on the origin certain restrictions are applied and the Pinentry may include an extra note on the origin. Supported values for origin are: local which is the default, remote to indicate a remote origin or browser for an operation requested by a web browser.

--no-common-certs-import

Suppress the import of common certificates on keybox creation.

All the long options may also be given in the configuration file after stripping off the two leading dashes.


Next: , Previous: , Up: Invoking GPGSM   [Contents][Index]

5.3 Configuration files

There are a few configuration files to control certain aspects of gpgsm’s operation. Unless noted, they are expected in the current home directory (see option --homedir).

gpgsm.conf

This is the standard configuration file read by gpgsm on startup. It may contain any valid long option; the leading two dashes may not be entered and the option may not be abbreviated. This default name may be changed on the command line (see gpgsm-option --options). You should backup this file.

common.conf

This is an optional configuration file read by gpgsm on startup. It may contain options pertaining to all components of GnuPG. Its current main use is for the "use-keyboxd" option.

policies.txt

This is a list of allowed CA policies. This file should list the object identifiers of the policies line by line. Empty lines and lines starting with a hash mark are ignored. Policies missing in this file and not marked as critical in the certificate will print only a warning; certificates with policies marked as critical and not listed in this file will fail the signature verification. You should backup this file.

For example, to allow only the policy 2.289.9.9, the file should look like this:

# Allowed policies
2.289.9.9
qualified.txt

This is the list of root certificates used for qualified certificates. They are defined as certificates capable of creating legally binding signatures in the same way as handwritten signatures are. Comments start with a hash mark and empty lines are ignored. Lines do have a length limit but this is not a serious limitation as the format of the entries is fixed and checked by gpgsm: A non-comment line starts with optional whitespace, followed by exactly 40 hex characters, white space and a lowercased 2 letter country code. Additional data delimited with by a white space is current ignored but might late be used for other purposes.

Note that even if a certificate is listed in this file, this does not mean that the certificate is trusted; in general the certificates listed in this file need to be listed also in trustlist.txt. This is a global file an installed in the sysconf directory (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/gnupg/qualified.txt).

Every time gpgsm uses a certificate for signing or verification this file will be consulted to check whether the certificate under question has ultimately been issued by one of these CAs. If this is the case the user will be informed that the verified signature represents a legally binding (“qualified”) signature. When creating a signature using such a certificate an extra prompt will be issued to let the user confirm that such a legally binding signature shall really be created.

Because this software has not yet been approved for use with such certificates, appropriate notices will be shown to indicate this fact.

help.txt

This is plain text file with a few help entries used with pinentry as well as a large list of help items for gpg and gpgsm. The standard file has English help texts; to install localized versions use filenames like help.LL.txt with LL denoting the locale. GnuPG comes with a set of predefined help files in the data directory (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/share/gnupg/gnupg/help.de.txt) and allows overriding of any help item by help files stored in the system configuration directory (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/gnupg/help.de.txt). For a reference of the help file’s syntax, please see the installed help.txt file.

com-certs.pem

This file is a collection of common certificates used to populated a newly created pubring.kbx. An administrator may replace this file with a custom one. The format is a concatenation of PEM encoded X.509 certificates. This global file is installed in the data directory (e.g. /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/share/gnupg/com-certs.pem).

Note that on larger installations, it is useful to put predefined files into the directory /etc/skel/.gnupg/ so that newly created users start up with a working configuration. For existing users a small helper script is provided to create these files (see Create .gnupg home directories).

For internal purposes gpgsm creates and maintains a few other files; they all live in the current home directory (see option --homedir). Only gpgsm may modify these files.

pubring.kbx

This a database file storing the certificates as well as meta information. For debugging purposes the tool kbxutil may be used to show the internal structure of this file. You should backup this file.

random_seed

This content of this file is used to maintain the internal state of the random number generator across invocations. The same file is used by other programs of this software too.

S.gpg-agent

If this file exists gpgsm will first try to connect to this socket for accessing gpg-agent before starting a new gpg-agent instance. Under Windows this socket (which in reality be a plain file describing a regular TCP listening port) is the standard way of connecting the gpg-agent.


5.4 Examples

$ gpgsm -er goo@bar.net <plaintext >ciphertext

5.5 Unattended Usage

gpgsm is often used as a backend engine by other software. To help with this a machine interface has been defined to have an unambiguous way to do this. This is most likely used with the --server command but may also be used in the standard operation mode by using the --status-fd option.


5.5.1 Automated signature checking

It is very important to understand the semantics used with signature verification. Checking a signature is not as simple as it may sound and so the operation is a bit complicated. In most cases it is required to look at several status lines. Here is a table of all cases a signed message may have:

The signature is valid

This does mean that the signature has been successfully verified, the certificates are all sane. However there are two subcases with important information: One of the certificates may have expired or a signature of a message itself as expired. It is a sound practise to consider such a signature still as valid but additional information should be displayed. Depending on the subcase gpgsm will issue these status codes:

signature valid and nothing did expire

GOODSIG, VALIDSIG, TRUST_FULLY

signature valid but at least one certificate has expired

EXPKEYSIG, VALIDSIG, TRUST_FULLY

signature valid but expired

EXPSIG, VALIDSIG, TRUST_FULLY Note, that this case is currently not implemented.

The signature is invalid

This means that the signature verification failed (this is an indication of a transfer error, a program error or tampering with the message). gpgsm issues one of these status codes sequences:

BADSIG
GOODSIG, VALIDSIG TRUST_NEVER
Error verifying a signature

For some reason the signature could not be verified, i.e. it cannot be decided whether the signature is valid or invalid. A common reason for this is a missing certificate.


5.5.2 CSR and certificate creation

The command --generate-key may be used along with the option --batch to either create a certificate signing request (CSR) or an X.509 certificate. This is controlled by a parameter file; the format of this file is as follows:

  • Text only, line length is limited to about 1000 characters.
  • UTF-8 encoding must be used to specify non-ASCII characters.
  • Empty lines are ignored.
  • Leading and trailing while space is ignored.
  • A hash sign as the first non white space character indicates a comment line.
  • Control statements are indicated by a leading percent sign, the arguments are separated by white space from the keyword.
  • Parameters are specified by a keyword, followed by a colon. Arguments are separated by white space.
  • The first parameter must be ‘Key-Type’, control statements may be placed anywhere.
  • The order of the parameters does not matter except for ‘Key-Type’ which must be the first parameter. The parameters are only used for the generated CSR/certificate; parameters from previous sets are not used. Some syntactically checks may be performed.
  • Key generation takes place when either the end of the parameter file is reached, the next ‘Key-Type’ parameter is encountered or at the control statement ‘%commit’ is encountered.

Control statements:

%echo text

Print text as diagnostic.

%dry-run

Suppress actual key generation (useful for syntax checking).

%commit

Perform the key generation. Note that an implicit commit is done at the next Key-Type parameter.

General Parameters:

Key-Type: algo

Starts a new parameter block by giving the type of the primary key. The algorithm must be capable of signing. This is a required parameter. The supported values for algo are ‘rsa’, ‘ecdsa’, and ‘eddsa’.

Key-Length: nbits

The requested length of a generated key in bits. Defaults to 3072. The value is ignored for ECC algorithms.

Key-Grip: hexstring

This is optional and used to generate a CSR or certificate for an already existing key. Key-Length will be ignored when given.

Key-Usage: usage-list

Space or comma delimited list of key usage, allowed values are ‘encrypt’, ‘sign’ and ‘cert’. This is used to generate the keyUsage extension. Please make sure that the algorithm is capable of this usage. Default is to allow encrypt and sign.

Name-DN: subject-name

This is the Distinguished Name (DN) of the subject in RFC-2253 format.

Name-Email: string

This is an email address for the altSubjectName. This parameter is optional but may occur several times to add several email addresses to a certificate.

Name-DNS: string

The is an DNS name for the altSubjectName. This parameter is optional but may occur several times to add several DNS names to a certificate.

Name-URI: string

This is an URI for the altSubjectName. This parameter is optional but may occur several times to add several URIs to a certificate.

Additional parameters used to create a certificate (in contrast to a certificate signing request):

Serial: sn

If this parameter is given an X.509 certificate will be generated. sn is expected to be a hex string representing an unsigned integer of arbitrary length. The special value ‘random’ can be used to create a 64 bit random serial number.

Issuer-DN: issuer-name

This is the DN name of the issuer in RFC-2253 format. If it is not set it will default to the subject DN and a special GnuPG extension will be included in the certificate to mark it as a standalone certificate.

Creation-Date: iso-date
Not-Before: iso-date

Set the notBefore date of the certificate. Either a date like ‘1986-04-26’ or ‘1986-04-26 12:00’ or a standard ISO timestamp like ‘19860426T042640’ may be used. The time is considered to be UTC. If it is not given the current date is used.

Expire-Date: iso-date
Not-After: iso-date

Set the notAfter date of the certificate. Either a date like ‘2063-04-05’ or ‘2063-04-05 17:00’ or a standard ISO timestamp like ‘20630405T170000’ may be used. The time is considered to be UTC. If it is not given a default value in the not too far future is used.

Signing-Key: keygrip

This gives the keygrip of the key used to sign the certificate. If it is not given a self-signed certificate will be created. For compatibility with future versions, it is suggested to prefix the keygrip with a ‘&’.

Hash-Algo: hash-algo

Use hash-algo for this CSR or certificate. The supported hash algorithms are: ‘sha1’, ‘sha256’, ‘sha384’ and ‘sha512’; they may also be specified with uppercase letters. The default is ‘sha256’.

Authority-Key-Id: hexstring

Insert the decoded value of hexstring as authorityKeyIdentifier. If this is not given and an ECC algorithm is used the public part of the certified public key is used as authorityKeyIdentifier. To inhibit any authorityKeyIdentifier use the special value none for hexstring.

Subject-Key-Id: hexstring

Insert the decoded value of hexstring as subjectKeyIdentifier. If this is not given and an ECC algorithm is used the public part of the signing key is used as authorityKeyIdentifier. To inhibit any subjectKeyIdentifier use the special value none for hexstring.


5.6 The Protocol the Server Mode Uses

Description of the protocol used to access GPGSM. GPGSM does implement the Assuan protocol and in addition provides a regular command line interface which exhibits a full client to this protocol (but uses internal linking). To start gpgsm as a server the command line the option --server must be used. Additional options are provided to select the communication method (i.e. the name of the socket).

We assume that the connection has already been established; see the Assuan manual for details.


5.6.1 Encrypting a Message

Before encryption can be done the recipient must be set using the command:

  RECIPIENT userID

Set the recipient for the encryption. userID should be the internal representation of the key; the server may accept any other way of specification. If this is a valid and trusted recipient the server does respond with OK, otherwise the return is an ERR with the reason why the recipient cannot be used, the encryption will then not be done for this recipient. If the policy is not to encrypt at all if not all recipients are valid, the client has to take care of this. All RECIPIENT commands are cumulative until a RESET or an successful ENCRYPT command.

  INPUT FD[=n] [--armor|--base64|--binary]

Set the file descriptor for the message to be encrypted to n. Obviously the pipe must be open at that point, the server establishes its own end. If the server returns an error the client should consider this session failed. If n is not given, this commands uses the last file descriptor passed to the application. See the assuan_sendfd function in the Libassuan manual, on how to do descriptor passing.

The --armor option may be used to advise the server that the input data is in PEM format, --base64 advises that a raw base-64 encoding is used, --binary advises of raw binary input (BER). If none of these options is used, the server tries to figure out the used encoding, but this may not always be correct.

  OUTPUT FD[=n] [--armor|--base64]

Set the file descriptor to be used for the output (i.e. the encrypted message). Obviously the pipe must be open at that point, the server establishes its own end. If the server returns an error the client should consider this session failed.

The option --armor encodes the output in PEM format, the --base64 option applies just a base-64 encoding. No option creates binary output (BER).

The actual encryption is done using the command

  ENCRYPT

It takes the plaintext from the INPUT command, writes to the ciphertext to the file descriptor set with the OUTPUT command, take the recipients from all the recipients set so far. If this command fails the clients should try to delete all output currently done or otherwise mark it as invalid. GPGSM does ensure that there will not be any security problem with leftover data on the output in this case.

This command should in general not fail, as all necessary checks have been done while setting the recipients. The input and output pipes are closed.


5.6.2 Decrypting a message

Input and output FDs are set the same way as in encryption, but INPUT refers to the ciphertext and OUTPUT to the plaintext. There is no need to set recipients. GPGSM automatically strips any S/MIME headers from the input, so it is valid to pass an entire MIME part to the INPUT pipe.

The decryption is done by using the command

  DECRYPT

It performs the decrypt operation after doing some check on the internal state (e.g. that all needed data has been set). Because it utilizes the GPG-Agent for the session key decryption, there is no need to ask the client for a protecting passphrase - GpgAgent takes care of this by requesting this from the user.


5.6.3 Signing a Message

Signing is usually done with these commands:

  INPUT FD[=n] [--armor|--base64|--binary]

This tells GPGSM to read the data to sign from file descriptor n.

  OUTPUT FD[=m] [--armor|--base64]

Write the output to file descriptor m. If a detached signature is requested, only the signature is written.

  SIGN [--detached]

Sign the data set with the INPUT command and write it to the sink set by OUTPUT. With --detached, a detached signature is created (surprise).

The key used for signing is the default one or the one specified in the configuration file. To get finer control over the keys, it is possible to use the command

  SIGNER userID

to set the signer’s key. userID should be the internal representation of the key; the server may accept any other way of specification. If this is a valid and trusted recipient the server does respond with OK, otherwise the return is an ERR with the reason why the key cannot be used, the signature will then not be created using this key. If the policy is not to sign at all if not all keys are valid, the client has to take care of this. All SIGNER commands are cumulative until a RESET is done. Note that a SIGN does not reset this list of signers which is in contrast to the RECIPIENT command.


5.6.4 Verifying a Message

To verify a message the command:

  VERIFY

is used. It does a verify operation on the message send to the input FD. The result is written out using status lines. If an output FD was given, the signed text will be written to that. If the signature is a detached one, the server will inquire about the signed material and the client must provide it.


5.6.5 Generating a Key

This is used to generate a new keypair, store the secret part in the PSE and the public key in the key database. We will probably add optional commands to allow the client to select whether a hardware token is used to store the key. Configuration options to GPGSM can be used to restrict the use of this command.

  GENKEY

GPGSM checks whether this command is allowed and then does an INQUIRY to get the key parameters, the client should then send the key parameters in the native format:

    S: INQUIRE KEY_PARAM native
    C: D foo:fgfgfg
    C: D bar
    C: END

Please note that the server may send Status info lines while reading the data lines from the client. After this the key generation takes place and the server eventually does send an ERR or OK response. Status lines may be issued as a progress indicator.


5.6.6 List available keys

To list the keys in the internal database or using an external key provider, the command:

  LISTKEYS  pattern

is used. To allow multiple patterns (which are ORed during the search) quoting is required: Spaces are to be translated into "+" or into "%20"; in turn this requires that the usual escape quoting rules are done.

  LISTSECRETKEYS pattern

Lists only the keys where a secret key is available.

The list commands are affected by the option

  OPTION list-mode=mode

where mode may be:

0

Use default (which is usually the same as 1).

1

List only the internal keys.

2

List only the external keys.

3

List internal and external keys.

Note that options are valid for the entire session.


5.6.7 Export certificates

To export certificate from the internal key database the command:

  EXPORT [--data [--armor] [--base64]] [--] pattern

is used. To allow multiple patterns (which are ORed) quoting is required: Spaces are to be translated into "+" or into "%20"; in turn this requires that the usual escape quoting rules are done.

If the --data option has not been given, the format of the output depends on what was set with the OUTPUT command. When using PEM encoding a few informational lines are prepended.

If the --data has been given, a target set via OUTPUT is ignored and the data is returned inline using standard D-lines. This avoids the need for an extra file descriptor. In this case the options --armor and --base64 may be used in the same way as with the OUTPUT command.


5.6.8 Import certificates

To import certificates into the internal key database, the command

  IMPORT [--re-import]

is used. The data is expected on the file descriptor set with the INPUT command. Certain checks are performed on the certificate. Note that the code will also handle PKCS#12 files and import private keys; a helper program is used for that.

With the option --re-import the input data is expected to a be a linefeed separated list of fingerprints. The command will re-import the corresponding certificates; that is they are made permanent by removing their ephemeral flag.


5.6.9 Delete certificates

To delete a certificate the command

  DELKEYS pattern

is used. To allow multiple patterns (which are ORed) quoting is required: Spaces are to be translated into "+" or into "%20"; in turn this requires that the usual escape quoting rules are done.

The certificates must be specified unambiguously otherwise an error is returned.


5.6.10 Retrieve an audit log

This command is used to retrieve an audit log.

GETAUDITLOG [--data] [--html]

If --data is used, the audit log is send using D-lines instead of being sent to the file descriptor given by an OUTPUT command. If --html is used, the output is formatted as an XHTML block. This is designed to be incorporated into a HTML document.


5.6.11 Return information about the process

This is a multipurpose function to return a variety of information.

GETINFO what

The value of what specifies the kind of information returned:

version

Return the version of the program.

pid

Return the process id of the process.

agent-check

Return OK if the agent is running.

cmd_has_option cmd opt

Return OK if the command cmd implements the option opt. The leading two dashes usually used with opt shall not be given.

offline

Return OK if the connection is in offline mode. This may be either due to a OPTION offline=1 or due to gpgsm being started with option --disable-dirmngr.


5.6.12 Session options

The standard Assuan option handler supports these options.

OPTION name[=value]

These names are recognized:

putenv

Change the session’s environment to be passed via gpg-agent to Pinentry. value is a string of the form <KEY>[=[<STRING>]]. If only <KEY> is given the environment variable <KEY> is removed from the session environment, if <KEY>= is given that environment variable is set to the empty string, and if <STRING> is given it is set to that string.

display

Set the session environment variable DISPLAY is set to value.

ttyname

Set the session environment variable GPG_TTY is set to value.

ttytype

Set the session environment variable TERM is set to value.

lc-ctype

Set the session environment variable LC_CTYPE is set to value.

lc-messages

Set the session environment variable LC_MESSAGES is set to value.

xauthority

Set the session environment variable XAUTHORITY is set to value.

pinentry-user-data

Set the session environment variable PINENTRY_USER_DATA is set to value.

include-certs

This option overrides the command line option --include-certs. A value of -2 includes all certificates except for the root certificate, -1 includes all certificates, 0 does not include any certificates, 1 includes only the signers certificate and all other positive values include up to value certificates starting with the signer cert.

list-mode

See gpgsm-cmd listkeys.

list-to-output

If value is true the output of the list commands (see gpgsm-cmd listkeys) is written to the file descriptor set with the last OUTPUT command. If value is false the output is written via data lines; this is the default.

with-validation

If value is true for each listed certificate the validation status is printed. This may result in the download of a CRL or the user being asked about the trustworthiness of a root certificate. The default is given by a command line option (see gpgsm-option --with-validation).

with-secret

If value is true certificates with a corresponding private key are marked by the list commands.

validation-model

This option overrides the command line option validation-model for the session. (See gpgsm-option --validation-model.)

with-key-data

This option globally enables the command line option --with-key-data. (See gpgsm-option --with-key-data.)

enable-audit-log

If value is true data to write an audit log is gathered. (See gpgsm-cmd getauditlog.)

allow-pinentry-notify

If this option is used notifications about the launch of a Pinentry are passed back to the client.

with-ephemeral-keys

If value is true ephemeral certificates are included in the output of the list commands.

no-encrypt-to

If this option is used all keys set by the command line option --encrypt-to are ignored.

offline

If value is true or value is not given all network access is disabled for this session. This is the same as the command line option --disable-dirmngr.


6 Invoking the SCDAEMON

The scdaemon is a daemon to manage smartcards. It is usually invoked by gpg-agent and in general not used directly.

See Option Index, for an index to scdaemon’s commands and options.


6.1 Commands

Commands are not distinguished from options except for the fact that only one command is allowed.

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help, -h

Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command.

--dump-options

Print a list of all available options and commands. Note that you cannot abbreviate this command.

--server

Run in server mode and wait for commands on the stdin. The default mode is to create a socket and listen for commands there.

--multi-server

Run in server mode and wait for commands on the stdin as well as on an additional Unix Domain socket. The server command GETINFO may be used to get the name of that extra socket.

--daemon

Run the program in the background. This option is required to prevent it from being accidentally running in the background.


6.2 Option Summary

--options file

Reads configuration from file instead of from the default per-user configuration file. The default configuration file is named scdaemon.conf and expected in the .gnupg directory directly below the home directory of the user.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

-v
--verbose

Outputs additional information while running. You can increase the verbosity by giving several verbose commands to gpgsm, such as ‘-vv’.

--debug-level level

Select the debug level for investigating problems. level may be a numeric value or a keyword:

none

No debugging at all. A value of less than 1 may be used instead of the keyword.

basic

Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.

advanced

More verbose debug messages. A value between 3 and 5 may be used instead of the keyword.

expert

Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.

guru

All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used.

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

Note: All debugging options are subject to change and thus should not be used by any application program. As the name says, they are only used as helpers to debug problems.

--debug flags

Set debug flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice.

--debug-all

Same as --debug=0xffffffff

--debug-wait n

When running in server mode, wait n seconds before entering the actual processing loop and print the pid. This gives time to attach a debugger.

--debug-ccid-driver

Enable debug output from the included CCID driver for smartcards. Using this option twice will also enable some tracing of the T=1 protocol. Note that this option may reveal sensitive data.

--debug-disable-ticker

This option disables all ticker functions like checking for card insertions.

--debug-allow-core-dump

For security reasons we won’t create a core dump when the process aborts. For debugging purposes it is sometimes better to allow core dump. This option enables it and also changes the working directory to /tmp when running in --server mode.

--debug-log-tid

This option appends a thread ID to the PID in the log output.

--debug-assuan-log-cats cats

Changes the active Libassuan logging categories to cats. The value for cats is an unsigned integer given in usual C-Syntax. A value of 0 switches to a default category. If this option is not used the categories are taken from the environment variable ASSUAN_DEBUG. Note that this option has only an effect if the Assuan debug flag has also been with the option --debug. For a list of categories see the Libassuan manual.

--no-detach

Don’t detach the process from the console. This is mainly useful for debugging.

--listen-backlog n

Set the size of the queue for pending connections. The default is 64. This option has an effect only if --multi-server is also used.

--log-file file

Append all logging output to file. This is very helpful in seeing what the agent actually does. Use socket:// to log to socket.

--pcsc-shared

Use shared mode to access the card via PC/SC. This is a somewhat dangerous option because Scdaemon assumes exclusive access to the card and for example caches certain information from the card. Use this option only if you know what you are doing.

--pcsc-driver library

Use library to access the smartcard reader. The current default is libpcsclite.so. Instead of using this option you might also want to install a symbolic link to the default file name (e.g. from libpcsclite.so.1).

--ctapi-driver library

Use library to access the smartcard reader. The current default is libtowitoko.so. Note that the use of this interface is deprecated; it may be removed in future releases.

--disable-ccid

Disable the integrated support for CCID compliant readers. This allows falling back to one of the other drivers even if the internal CCID driver can handle the reader. Note, that CCID support is only available if libusb was available at build time.

--reader-port number_or_string

This option may be used to specify the port of the card terminal. A value of 0 refers to the first serial device; add 32768 to access USB devices. The default is 32768 (first USB device). PC/SC or CCID readers might need a string here; run the program in verbose mode to get a list of available readers. The default is then the first reader found.

To get a list of available CCID readers you may use this command:

  echo scd getinfo reader_list \
    | gpg-connect-agent --decode | awk '/^D/ {print $2}'
--card-timeout n

This option is deprecated. In GnuPG 2.0, it used to be used for DISCONNECT command to control timing issue. Since DISCONNECT command works synchronously, it has no effect.

--enable-pinpad-varlen

Please specify this option when the card reader supports variable length input for pinpad (default is no). For known readers (listed in ccid-driver.c and apdu.c), this option is not needed. Note that if your card reader doesn’t supports variable length input but you want to use it, you need to specify your pinpad request on your card.

--disable-pinpad

Even if a card reader features a pinpad, do not try to use it.

--deny-admin

This option disables the use of admin class commands for card applications where this is supported. Currently we support it for the OpenPGP card. This option is useful to inhibit accidental access to admin class command which could ultimately lock the card through wrong PIN numbers. Note that GnuPG versions older than 2.0.11 featured an --allow-admin option which was required to use such admin commands. This option has no more effect today because the default is now to allow admin commands.

--disable-application name

This option disables the use of the card application named name. This is mainly useful for debugging or if a application with lower priority should be used by default.

--application-priority namelist

This option allows to change the order in which applications of a card a tried if no specific application was requested. namelist is a space or comma delimited list of application names. Unknown names are simply skipped. Applications not mentioned in the list are put in the former order at the end of the new priority list.

To get the list of current active applications, use

    gpg-connect-agent 'scd getinfo app_list' /bye

All the long options may also be given in the configuration file after stripping off the two leading dashes.


6.3 Description of card applications

scdaemon supports the card applications as described below.


6.3.1 The OpenPGP card application “openpgp”

This application is currently only used by gpg but may in future also be useful with gpgsm. Version 1 and version 2 of the card is supported.

The specifications for these cards are available at
http://g10code.com/docs/openpgp-card-1.0.pdf and
http://g10code.com/docs/openpgp-card-2.0.pdf.


6.3.2 The Telesec NetKey card “nks”

This is the main application of the Telesec cards as available in Germany. It is a superset of the German DINSIG card. The card is used by gpgsm.


6.3.3 The DINSIG card application “dinsig”

This is an application as described in the German draft standard DIN V 66291-1. It is intended to be used by cards supporting the German signature law and its bylaws (SigG and SigV).


6.3.4 The PKCS#15 card application “p15”

This is common framework for smart card applications. It is used by gpgsm.


6.3.5 The Geldkarte card application “geldkarte”

This is a simple application to display information of a German Geldkarte. The Geldkarte is a small amount debit card application which comes with almost all German banking cards.


6.3.6 The SmartCard-HSM card application “sc-hsm”

This application adds read-only support for keys and certificates stored on a SmartCard-HSM.

To generate keys and store certificates you may use OpenSC or the tools from OpenSCDP.

The SmartCard-HSM cards requires a card reader that supports Extended Length APDUs.


6.3.7 The Undefined card application “undefined”

This is a stub application to allow the use of the APDU command even if no supported application is found on the card. This application is not used automatically but must be explicitly requested using the SERIALNO command.


6.4 Configuration files

There are a few configuration files to control certain aspects of scdaemons’s operation. Unless noted, they are expected in the current home directory (see option --homedir).

scdaemon.conf

This is the standard configuration file read by scdaemon on startup. It may contain any valid long option; the leading two dashes may not be entered and the option may not be abbreviated. This default name may be changed on the command line (see option --options).

scd-event

If this file is present and executable, it will be called on every card reader’s status change. An example of this script is provided with the distribution

reader_n.status

This file is created by scdaemon to let other applications now about reader status changes. Its use is now deprecated in favor of scd-event.


6.5 Examples

$ scdaemon --server -v

6.6 Scdaemon’s Assuan Protocol

The SC-Daemon should be started by the system to provide access to external tokens. Using Smartcards on a multi-user system does not make much sense except for system services, but in this case no regular user accounts are hosted on the machine.

A client connects to the SC-Daemon by connecting to the socket named /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/run/gnupg/scdaemon/socket, configuration information is read from /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/etc/gnupg/scdaemon.conf

Each connection acts as one session, SC-Daemon takes care of synchronizing access to a token between sessions.


6.6.1 Return the serial number

This command should be used to check for the presence of a card. It is special in that it can be used to reset the card. Most other commands will return an error when a card change has been detected and the use of this function is therefore required.

Background: We want to keep the client clear of handling card changes between operations; i.e. the client can assume that all operations are done on the same card unless he call this function.

  SERIALNO

Return the serial number of the card using a status response like:

  S SERIALNO D27600000000000000000000

The serial number is the hex encoded value identified by the 0x5A tag in the GDO file (FIX=0x2F02).


6.6.2 Read all useful information from the card

  LEARN [--force]

Learn all useful information of the currently inserted card. When used without the --force option, the command might do an INQUIRE like this:

      INQUIRE KNOWNCARDP <hexstring_with_serialNumber>

The client should just send an END if the processing should go on or a CANCEL to force the function to terminate with a cancel error message. The response of this command is a list of status lines formatted as this:

     S KEYPAIRINFO hexstring_with_keygrip hexstring_with_id

If there is no certificate yet stored on the card a single "X" is returned in hexstring_with_keygrip.


6.6.3 Return a certificate

 READCERT hexified_certid|keyid

This function is used to read a certificate identified by hexified_certid from the card. With OpenPGP cards the keyid OpenPGP.3 may be used to read the certificate of version 2 cards.


6.6.4 Return a public key

READKEY hexified_certid

Return the public key for the given cert or key ID as an standard S-Expression.


6.6.5 Signing data with a Smartcard

To sign some data the caller should use the command

 SETDATA hexstring

to tell scdaemon about the data to be signed. The data must be given in hex notation. The actual signing is done using the command

  PKSIGN keyid

where keyid is the hexified ID of the key to be used. The key id may have been retrieved using the command LEARN. If another hash algorithm than SHA-1 is used, that algorithm may be given like:

  PKSIGN --hash=algoname keyid

With algoname are one of sha1, rmd160 or md5.


6.6.6 Decrypting data with a Smartcard

To decrypt some data the caller should use the command

 SETDATA hexstring

to tell scdaemon about the data to be decrypted. The data must be given in hex notation. The actual decryption is then done using the command

  PKDECRYPT keyid

where keyid is the hexified ID of the key to be used.

If the card is aware of the apdding format a status line with padding information is send before the plaintext data. The key for this status line is PADDING with the only defined value being 0 and meaning padding has been removed.


6.6.7 Read an attribute’s value

TO BE WRITTEN.


6.6.8 Update an attribute’s value

TO BE WRITTEN.


6.6.9 Write a key to a card

  WRITEKEY [--force] keyid

This command is used to store a secret key on a smartcard. The allowed keyids depend on the currently selected smartcard application. The actual keydata is requested using the inquiry KEYDATA and need to be provided without any protection. With --force set an existing key under this keyid will get overwritten. The key data is expected to be the usual canonical encoded S-expression.

A PIN will be requested in most cases. This however depends on the actual card application.


6.6.10 Generate a new key on-card

TO BE WRITTEN.


6.6.11 Return random bytes generated on-card

TO BE WRITTEN.


6.6.12 Change PINs

   PASSWD [--reset] [--nullpin] chvno

Change the PIN or reset the retry counter of the card holder verification vector number chvno. The option --nullpin is used to initialize the PIN of TCOS cards (6 byte NullPIN only).


6.6.13 Perform a VERIFY operation

  CHECKPIN idstr

Perform a VERIFY operation without doing anything else. This may be used to initialize a the PIN cache earlier to long lasting operations. Its use is highly application dependent:

OpenPGP

Perform a simple verify operation for CHV1 and CHV2, so that further operations won’t ask for CHV2 and it is possible to do a cheap check on the PIN: If there is something wrong with the PIN entry system, only the regular CHV will get blocked and not the dangerous CHV3. idstr is the usual card’s serial number in hex notation; an optional fingerprint part will get ignored.

There is however a special mode if idstr is suffixed with the literal string [CHV3]: In this case the Admin PIN is checked if and only if the retry counter is still at 3.


6.6.14 Perform a RESTART operation

  RESTART

Restart the current connection; this is a kind of warm reset. It deletes the context used by this connection but does not actually reset the card.

This is used by gpg-agent to reuse a primary pipe connection and may be used by clients to backup from a conflict in the serial command; i.e. to select another application.


6.6.15 Send a verbatim APDU to the card

  APDU [--atr] [--more] [--exlen[=n]] [hexstring]

Send an APDU to the current reader. This command bypasses the high level functions and sends the data directly to the card. hexstring is expected to be a proper APDU. If hexstring is not given no commands are send to the card; However the command will implicitly check whether the card is ready for use.

Using the option --atr returns the ATR of the card as a status message before any data like this:

     S CARD-ATR 3BFA1300FF813180450031C173C00100009000B1

Using the option --more handles the card status word MORE_DATA (61xx) and concatenate all responses to one block.

Using the option --exlen the returned APDU may use extended length up to N bytes. If N is not given a default value is used (currently 4096).


7 How to Specify a User Id

There are different ways to specify a user ID to GnuPG. Some of them are only valid for gpg others are only good for gpgsm. Here is the entire list of ways to specify a key:

Please note that we have reused the hash mark identifier which was used in old GnuPG versions to indicate the so called local-id. It is not anymore used and there should be no conflict when used with X.509 stuff.

Using the RFC-2253 format of DNs has the drawback that it is not possible to map them back to the original encoding, however we don’t have to do this because our key database stores this encoding as meta data.


8 Trust Values

Trust values are used to indicate ownertrust and validity of keys and user IDs. They are displayed with letters or strings:

-
unknown

No ownertrust assigned / not yet calculated.

e
expired

Trust calculation has failed; probably due to an expired key.

q
undefined, undef

Not enough information for calculation.

n
never

Never trust this key.

m
marginal

Marginally trusted.

f
full

Fully trusted.

u
ultimate

Ultimately trusted.

r
revoked

For validity only: the key or the user ID has been revoked.

?
err

The program encountered an unknown trust value.


Next: , Previous:   [Contents][Index]

9 Smart Card Tool

GnuPG comes with a tool to administrate smart cards and USB tokens. This tool is an enhanced version of the --edit-key command available with gpg.


9.1 Administrate smart cards.

The gpg-card is used to administrate smart cards and USB tokens. It provides a superset of features from gpg --card-edit an can be considered a frontend to scdaemon which is a daemon started by gpg-agent to handle smart cards.

If gpg-card is invoked without commands an interactive mode is used.

If gpg-card is invoked with one or more commands the same commands as available in the interactive mode are run from the command line. These commands need to be delimited with a double-dash. If a double-dash or a shell specific character is required as part of a command the entire command needs to be put in quotes. If one of those commands returns an error the remaining commands are not anymore run unless the command was prefixed with a single dash.

A list of commands is available by using the command help and a brief description of each command is printed by using help CMD. See the section COMMANDS for a full description.

See the NOTES sections for instructions pertaining to specific cards or card applications.

gpg-card understands these options:

--with-colons

This option has currently no effect.

--status-fd n

Write special status strings to the file descriptor n. This program returns only the status messages SUCCESS or FAILURE which are helpful when the caller uses a double fork approach and can’t easily get the return code of the process.

--verbose

Enable extra informational output.

--quiet

Disable almost all informational output.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.

--no-autostart

Do not start the gpg-agent if it has not yet been started and its service is required. This option is mostly useful on machines where the connection to gpg-agent has been redirected to another machines.

--no-history

In interactive mode the command line history is usually saved and restored to and from a file below the GnuPG home directory. This option inhibits the use of that file.

--agent-program file

Specify the agent program to be started if none is running. The default value is determined by running gpgconf with the option --list-dirs.

--gpg-program file

Specify a non-default gpg binary to be used by certain commands.

--gpgsm-program file

Specify a non-default gpgsm binary to be used by certain commands.

--chuid uid

Change the current user to uid which may either be a number or a name. This can be used from the root account to run gpg-card for another user. If uid is not the current UID a standard PATH is set and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This option has only an effect when used on the command line. This option has currently no effect at all on Windows.

gpg-card understands the following commands, which have options of their own. The pseudo-option ‘--’ can be used to separate command options from arguments; if this pseudo option is used on the command line the entire command with options and arguments must be quoted, so that it is not mixed up with the ‘--’ as used on the command line to separate commands. Note that a short online help is available for all commands by prefixing them with “help”. Command completion in the interactive mode is also supported.

AUTHENTICATE [--setkey] [--raw] [< file]|key]
AUTH

Authenticate to the card. Perform a mutual autentication either by reading the key from file or by taking it from the command line as key. Without the option --raw the key is expected to be hex encoded. To install a new administration key --setkey is used; this requires a prior authentication with the old key. This is used with PIV cards.

CAFPR [--clear] N

Change the CA fingerprint number N of an OpenPGP card. N must be in the range 1 to 3. The option --clear clears the specified CA fingerprint N or all of them if N is 0 or not given.

FACTORY-RESET

Do a complete reset of some OpenPGP and PIV cards. This command deletes all data and keys and resets the PINs to their default. Don’t worry, you need to confirm before the command proceeds.

FETCH

Retrieve a key using the URL data object of an OpenPGP card or if that is missing using the stored fingerprint.

FORCESIG

Toggle the forcesig flag of an OpenPGP card.

GENERATE [--force] [--algo=algo{+algo2}] keyref

Create a new key on a card. Use --force to overwrite an existing key. Use "help" for algo to get a list of known algorithms. For OpenPGP cards several algos may be given. Note that the OpenPGP key generation is done interactively unless --algo or keyref are given.

KDF-SETUP

Prepare the OpenPGP card KDF feature for this card.

LANG [--clear]

Change the language info for the card. This info can be used by applications for a personalized greeting. Up to 4 two-digit language identifiers can be entered as a preference. The option --clear removes all identifiers. GnuPG does not use this info.

LIST [--cards] [--apps] [--info] [--no-key-lookup] [n] [app]
L

This command reads all information from the current card and display them in a human readable format. The first section shows generic information vaialable for all cards. The next section shows information pertaining to keys which depend on the actual card and application.

With n given select and list the n-th card; with app also given select that application. To select an app on the current card use "-" for n. The serial number of the card may be used instead of n.

The option --cards lists the serial numbers of available cards. The option --apps lists all card applications. The option --info selects a card and prints its serial number. The option --no-key-lookup suppresses the listing of matching OpenPGP or X.509 keys.

LOGIN [--clear] [< file]

Set the login data object of OpenPGP cards. If file is given the data is is read from that file. This allows to store binary data in the login field. The option --clear deletes the login data object.

NAME [--clear]

Set the name field of an OpenPGP card. With option --clear the stored name is cleared off the card.

PASSWD [--reset|--nullpin] [pinref]

Change or unblock the PINs. Note that in interactive mode and without a pinref a menu is presented for certain cards." In non-interactive mode and without a pinref a default value i used for these cards. The option --reset is used with TCOS cards to reset the PIN using the PUK or vice versa; the option –nullpin is used for these cards to set the intial PIN.

PRIVATEDO [--clear] n [< file]

Change the private data object n of an OpenPGP card. n must be in the range 1 to 4. If file is given the data is is read from that file. The option --clear clears the data.

QUIT
Q

Stop processing and terminate gpg-card.

READCERT [--openpgp] certref > file

Read the certificate for key certref and store it in file. With option --openpgp an OpenPGP keyblock wrapped in a dedicated CMS content type (OID=1.3.6.1.4.1.11591.2.3.1) is expected and extracted to file. Note that for current OpenPGP cards a certificate may only be available at the certref "OPENPGP.3".

RESET

Send a reset to the card daemon.

SALUTATION [--clear]
SALUT

Change the salutation info for the card. This info can be used by applications for a personalized greeting. The option --clear removes this data object. GnuPG does not use this info.

UIF N [on|off|permanent]

Change the User Interaction Flag. That flags tells whether the confirmation button of a token shall be used. n must in the range 1 to 3. "permanent" is the same as "on" but the flag can’t be changed anmore.

UNBLOCK

Unblock a PIN using a PUK or Reset Code. Note that OpenPGP cards prior to version 2 can’t use this; instead the PASSWD can be used to set a new PIN.

URL [--clear]

Set the URL data object of an OpenPGP card. That data object can be used by by gpg’s --fetch command to retrieve the full public key. The option --clear deletes the content of that data object.

VERIFY [chvid]

Verify the PIN identified by chvid or the default PIN.

WRITECERT certref < file
WRITECERT --openpgp certref [< file|fpr]
WRITECERT --clear certref

Write a certificate to the card under the id certref. The option --clear removes the certificate from the card. The option --openpgp expects an OpenPGP keyblock and stores it encapsulated in a CMS container; the keyblock is taken from file or directly from the OpenPGP key identified by fingerprint fpr.

WRITEKEY [--force] keyref keygrip

Write a private key object identified by keygrip to the card under the id keyref. Option --force allows overwriting an existing key.

YUBIKEY cmd args

Various commands pertaining to Yubikey tokens with cmd being:

LIST

List supported and enabled Yubikey applications.

ENABLE usb|nfc|all [otp|u2f|opgp|piv|oath|fido2|all]
DISABLE

Enable or disable the specified or all applications on the given interface.

The support for OpenPGP cards in gpg-card is not yet complete. For missing features, please continue to use gpg --card-edit.

GnuPG has support for PIV cards (“Personal Identity Verification” as specified by NIST Special Publication 800-73-4). This section describes how to initialize (personalize) a fresh Yubikey token featuring the PIV application (requires Yubikey-5). We assume that the credentials have not yet been changed and thus are:

Authentication key

This is a 24 byte key described by the hex string
010203040506070801020304050607080102030405060708.

PIV Application PIN

This is the string 123456.

PIN Unblocking Key

This is the string 12345678.

See the example section on how to change these defaults. For production use it is important to use secure values for them. Note that the Authentication Key is not queried via the usual Pinentry dialog but needs to be entered manually or read from a file. The use of a dedicated machine to personalize tokens is strongly suggested.

To see what is on the card, the command list can be given. We will use the interactive mode in the following (the string gpg/card> is the prompt). An example output for a fresh card is:

gpg/card> list
Reader ...........: 1050:0407:X:0
Card type ........: yubikey
Card firmware ....: 5.1.2
Serial number ....: D2760001240102010006090746250000
Application type .: OpenPGP
Version ..........: 2.1
[...]

It can be seen by the “Application type” line that GnuPG selected the OpenPGP application of the Yubikey. This is because GnuPG assigns the highest priority to the OpenPGP application. To use the PIV application of the Yubikey several methods can be used:

With a Yubikey 5 or later the OpenPGP application on the Yubikey can be disabled:

gpg/card> yubikey disable all opgp
gpg/card> yubikey list
Application  USB    NFC
-----------------------
OTP          yes    yes
U2F          yes    yes
OPGP         no     no
PIV          yes    no
OATH         yes    yes
FIDO2        yes    yes
gpg/card> reset

The reset is required so that the GnuPG system rereads the card. Note that disabled applications keep all their data and can at any time be re-enabled (use help yubikey).

Another option, which works for all Yubikey versions, is to disable the support for OpenPGP cards in scdaemon. This is done by adding the line

disable-application openpgp

to ~/.gnupg/scdaemon.conf and by restarting scdaemon, either by killing the process or by using gpgconf --kill scdaemon. Finally the default order in which card applications are tried by scdaemon can be changed. For example to prefer PIV over OpenPGP it is sufficient to add

application-priority piv

to ~/.gnupg/scdaemon.conf and to restart scdaemon. This has an effect only on tokens which support both, PIV and OpenPGP, but does not hamper the use of OpenPGP only tokens.

With one of these methods employed the list command of gpg-card shows this:

gpg/card> list
Reader ...........: 1050:0407:X:0
Card type ........: yubikey
Card firmware ....: 5.1.2
Serial number ....: FF020001008A77C1
Application type .: PIV
Version ..........: 1.0
Displayed s/n ....: yk-9074625
PIN usage policy .: app-pin
PIN retry counter : - 3 -
PIV authentication: [none]
      keyref .....: PIV.9A
Card authenticat. : [none]
      keyref .....: PIV.9E
Digital signature : [none]
      keyref .....: PIV.9C
Key management ...: [none]
      keyref .....: PIV.9D

In case several tokens are plugged into the computer, gpg-card will show only one. To show another token the number of the token (0, 1, 2, ...) can be given as an argument to the list command. The command list --cards prints a list of all inserted tokens.

Note that the “Displayed s/n” is printed on the token and also shown in Pinentry prompts asking for the PIN. The four standard key slots are always shown, if other key slots are initialized they are shown as well. The PIV authentication key (internal reference PIV.9A) is used to authenticate the card and the card holder. The use of the associated private key is protected by the Application PIN which needs to be provided once and the key can the be used until the card is reset or removed from the reader or USB port. GnuPG uses this key with its Secure Shell support. The Card authentication key (PIV.9E) is also known as the CAK and used to support physical access applications. The private key is not protected by a PIN and can thus immediately be used. The Digital signature key (PIV.9C) is used to digitally sign documents. The use of the associated private key is protected by the Application PIN which needs to be provided for each signing operation. The Key management key (PIV.9D) is used for encryption. The use of the associated private key is protected by the Application PIN which needs to be provided only once so that decryption operations can then be done until the card is reset or removed from the reader or USB port.

We now generate three of the four keys. Note that GnuPG does currently not use the the Card authentication key; however, that key is mandatory by the PIV standard and thus we create it too. Key generation requires that we authenticate to the card. This can be done either on the command line (which would reveal the key):

gpg/card> auth 010203040506070801020304050607080102030405060708

or by reading the key from a file. That file needs to consist of one LF terminated line with the hex encoded key (as above):

gpg/card> auth < myauth.key

As usual ‘help auth’ gives help for this command. An error message is printed if a non-matching key is used. The authentication is valid until a reset of the card or until the card is removed from the reader or the USB port. Note that that in non-interactive mode the ‘<’ needs to be quoted so that the shell does not interpret it as a its own redirection symbol.

Here are the actual commands to generate the keys:

gpg/card> generate --algo=nistp384 PIV.9A
PIV card no. yk-9074625 detected
gpg/card> generate --algo=nistp256 PIV.9E
PIV card no. yk-9074625 detected
gpg/card> generate --algo=rsa2048 PIV.9C
PIV card no. yk-9074625 detected

If a key has already been created for one of the slots an error will be printed; to create a new key anyway the option ‘--force’ can be used. Note that only the private and public keys have been created but no certificates are stored in the key slots. In fact, GnuPG uses its own non-standard method to store just the public key in place of the the certificate. Other application will not be able to make use these keys until gpgsm or another tool has been used to create and store the respective certificates. Let us see what the list command now shows:

gpg/card> list
Reader ...........: 1050:0407:X:0
Card type ........: yubikey
Card firmware ....: 5.1.2
Serial number ....: FF020001008A77C1
Application type .: PIV
Version ..........: 1.0
Displayed s/n ....: yk-9074625
PIN usage policy .: app-pin
PIN retry counter : - 3 -
PIV authentication: 213D1825FDE0F8240CB4E4229F01AF90AC658C2E
      keyref .....: PIV.9A  (auth)
      algorithm ..: nistp384
Card authenticat. : 7A53E6CFFE7220A0E646B4632EE29E5A7104499C
      keyref .....: PIV.9E  (auth)
      algorithm ..: nistp256
Digital signature : 32A6C6FAFCB8421878608AAB452D5470DD3223ED
      keyref .....: PIV.9C  (sign,cert)
      algorithm ..: rsa2048
Key management ...: [none]
      keyref .....: PIV.9D

The primary information for each key is the keygrip, a 40 byte hex-string identifying the key. This keygrip is a unique identifier for the specific parameters of a key. It is used by gpg-agent and other parts of GnuPG to associate a private key to its protocol specific certificate format (X.509, OpenPGP, or SecureShell). Below the keygrip the key reference along with the key usage capabilities are show. Finally the algorithm is printed in the format used by gpg. At that point no other information is shown because for these new keys gpg won’t be able to find matching certificates.

Although we could have created the Key management key also with the generate command, we will create that key off-card so that a backup exists. To accomplish this a key needs to be created with either gpg or gpgsm or imported in one of these tools. In our example we create a self-signed X.509 certificate (exit the gpg-card tool, first):

$ gpgsm --gen-key -o encr.crt
   (1) RSA
   (2) Existing key
   (3) Existing key from card
Your selection? 1
What keysize do you want? (3072) 2048
Requested keysize is 2048 bits
Possible actions for a RSA key:
   (1) sign, encrypt
   (2) sign
   (3) encrypt
Your selection? 3
Enter the X.509 subject name: CN=Encryption key for yk-9074625,O=example,C=DE
Enter email addresses (end with an empty line):
> otto@example.net
>
Enter DNS names (optional; end with an empty line):
>
Enter URIs (optional; end with an empty line):
>
Create self-signed certificate? (y/N) y
These parameters are used:
    Key-Type: RSA
    Key-Length: 2048
    Key-Usage: encrypt
    Serial: random
    Name-DN: CN=Encryption key for yk-9074625,O=example,C=DE
    Name-Email: otto@example.net

Proceed with creation? (y/N)
Now creating self-signed certificate.  This may take a while ...
gpgsm: about to sign the certificate for key: &34798AAFE0A7565088101CC4AE31C5C8C74461CB
gpgsm: certificate created
Ready.
$ gpgsm --import encr.crt
gpgsm: certificate imported
gpgsm: total number processed: 1
gpgsm:               imported: 1

Note the last step which imported the created certificate. If you you instead created a certificate signing request (CSR) instead of a self-signed certificate and sent this off to a CA you would do the same import step with the certificate received from the CA. Take note of the keygrip (prefixed with an ampersand) as shown during the certificate creation or listed it again using ‘gpgsm --with-keygrip -k otto@example.net’. Now to move the key and certificate to the card start gpg-card again and enter:

gpg/card> writekey PIV.9D 34798AAFE0A7565088101CC4AE31C5C8C74461CB
gpg/card> writecert PIV.9D < encr.crt

If you entered a passphrase to protect the private key, you will be asked for it via the Pinentry prompt. On success the key and the certificate has been written to the card and a list command shows:

[...]
Key management ...: 34798AAFE0A7565088101CC4AE31C5C8C74461CB
      keyref .....: PIV.9D  (encr)
      algorithm ..: rsa2048
      used for ...: X.509
        user id ..: CN=Encryption key for yk-9074625,O=example,C=DE
        user id ..: <otto@example.net>

In case the same key (identified by the keygrip) has been used for several certificates you will see several “used for” parts. With this the encryption key is now fully functional and can be used to decrypt messages encrypted to this certificate. TAKE CARE: the original key is still stored on-disk and should be moved to a backup medium. This can simply be done by copying the file 34798AAFE0A7565088101CC4AE31C5C8C74461CB.key from the directory ~/.gnupg/private-keys-v1.d/ to the backup medium and deleting the file at its original place.

The final example is to create a self-signed certificate for digital signatures. Leave gpg-card using quit or by pressing Control-D and use gpgsm:

$ gpgsm --learn
$ gpgsm --gen-key -o sign.crt
Please select what kind of key you want:
   (1) RSA
   (2) Existing key
   (3) Existing key from card
Your selection? 3
Serial number of the card: FF020001008A77C1
Available keys:
   (1) 213D1825FDE0F8240CB4E4229F01AF90AC658C2E PIV.9A nistp384
   (2) 7A53E6CFFE7220A0E646B4632EE29E5A7104499C PIV.9E nistp256
   (3) 32A6C6FAFCB8421878608AAB452D5470DD3223ED PIV.9C rsa2048
   (4) 34798AAFE0A7565088101CC4AE31C5C8C74461CB PIV.9D rsa2048
Your selection? 3
Possible actions for a RSA key:
   (1) sign, encrypt
   (2) sign
   (3) encrypt
Your selection? 2
Enter the X.509 subject name: CN=Signing key for yk-9074625,O=example,C=DE
Enter email addresses (end with an empty line):
> otto@example.net
>
Enter DNS names (optional; end with an empty line):
>
Enter URIs (optional; end with an empty line):
>
Create self-signed certificate? (y/N)
These parameters are used:
    Key-Type: card:PIV.9C
    Key-Length: 1024
    Key-Usage: sign
    Serial: random
    Name-DN: CN=Signing key for yk-9074625,O=example,C=DE
    Name-Email: otto@example.net

Proceed with creation? (y/N) y
Now creating self-signed certificate.  This may take a while ...
gpgsm: about to sign the certificate for key: &32A6C6FAFCB8421878608AAB452D5470DD3223ED
gpgsm: certificate created
Ready.
$ gpgsm --import sign.crt
gpgsm: certificate imported
gpgsm: total number processed: 1
gpgsm:               imported: 1

The use of ‘gpgsm --learn’ is currently necessary so that gpg-agent knows what keys are available on the card. The need for this command will eventually be removed. The remaining commands are similar to the creation of an on-disk key. However, here we select the ‘Digital signature’ key. During the creation process you will be asked for the Application PIN of the card. The final step is to write the certificate to the card using gpg-card:

gpg/card> writecert PIV.9C < sign.crt

By running list again we will see the fully initialized card:

Reader ...........: 1050:0407:X:0
Card type ........: yubikey
Card firmware ....: 5.1.2
Serial number ....: FF020001008A77C1
Application type .: PIV
Version ..........: 1.0
Displayed s/n ....: yk-9074625
PIN usage policy .: app-pin
PIN retry counter : - [verified] -
PIV authentication: 213D1825FDE0F8240CB4E4229F01AF90AC658C2E
      keyref .....: PIV.9A  (auth)
      algorithm ..: nistp384
Card authenticat. : 7A53E6CFFE7220A0E646B4632EE29E5A7104499C
      keyref .....: PIV.9E  (auth)
      algorithm ..: nistp256
Digital signature : 32A6C6FAFCB8421878608AAB452D5470DD3223ED
      keyref .....: PIV.9C  (sign,cert)
      algorithm ..: rsa2048
      used for ...: X.509
        user id ..: CN=Signing key for yk-9074625,O=example,C=DE
        user id ..: <otto@example.net>
Key management ...: 34798AAFE0A7565088101CC4AE31C5C8C74461CB
      keyref .....: PIV.9D  (encr)
      algorithm ..: rsa2048
      used for ...: X.509
        user id ..: CN=Encryption key for yk-9074625,O=example,C=DE
        user id ..: <otto@example.net>

It is now possible to sign and to encrypt with this card using gpgsm and to use the ‘PIV authentication’ key with ssh:

$ ssh-add -l
384 SHA256:0qnJ0Y0ehWxKcx2frLfEljf6GCdlO55OZed5HqGHsaU cardno:yk-9074625 (ECDSA)

As usual use ssh-add with the uppercase ‘-L’ to list the public ssh key. To use the certificates with Thunderbird or Mozilla, please consult the Scute manual for details.

If you want to use the same PIV keys also for OpenPGP (for example on a Yubikey to avoid switching between OpenPGP and PIV), this is also possible:

$ gpgsm --learn
$ gpg --full-gen-key
Please select what kind of key you want:
   (1) RSA and RSA (default)
   (2) DSA and Elgamal
   (3) DSA (sign only)
   (4) RSA (sign only)
  (14) Existing key from card
Your selection? 14
Serial number of the card: FF020001008A77C1
Available keys:
   (1) 213D1825FDE0F8240CB4E4229F01AF90AC658C2E PIV.9A nistp384 (auth)
   (2) 7A53E6CFFE7220A0E646B4632EE29E5A7104499C PIV.9E nistp256 (auth)
   (3) 32A6C6FAFCB8421878608AAB452D5470DD3223ED PIV.9C rsa2048 (cert,sign)
   (4) 34798AAFE0A7565088101CC4AE31C5C8C74461CB PIV.9D rsa2048 (encr)
Your selection? 3
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0)
Key does not expire at all
Is this correct? (y/N) y

GnuPG needs to construct a user ID to identify your key.

Real name:
Email address: otto@example.net
Comment:
You selected this USER-ID:
    "otto@example.net"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
gpg: key C3AFA9ED971BB365 marked as ultimately trusted
gpg: revocation certificate stored as '[...]D971BB365.rev'
public and secret key created and signed.

Note that this key cannot be used for encryption.  You may want to use
the command "--edit-key" to generate a subkey for this purpose.
pub   rsa2048 2019-04-04 [SC]
      7F899AE2FB73159DD68A1B20C3AFA9ED971BB365
uid                      otto@example.net

Note that you will be asked two times to enter the PIN of your PIV card. If you run gpg in --expert mode you will also ge given the option to change the usage flags of the key. The next typescript shows how to add the encryption subkey:

$ gpg --edit-key 7F899AE2FB73159DD68A1B20C3AFA9ED971BB365
Secret key is available.

sec  rsa2048/C3AFA9ED971BB365
     created: 2019-04-04  expires: never       usage: SC
     card-no: FF020001008A77C1
     trust: ultimate      validity: ultimate
[ultimate] (1). otto@example.net
gpg> addkey
Secret parts of primary key are stored on-card.
Please select what kind of key you want:
   (3) DSA (sign only)
   (4) RSA (sign only)
   (5) Elgamal (encrypt only)
   (6) RSA (encrypt only)
  (14) Existing key from card
Your selection? 14
Serial number of the card: FF020001008A77C1
Available keys:
   (1) 213D1825FDE0F8240CB4E4229F01AF90AC658C2E PIV.9A nistp384 (auth)
   (2) 7A53E6CFFE7220A0E646B4632EE29E5A7104499C PIV.9E nistp256 (auth)
   (3) 32A6C6FAFCB8421878608AAB452D5470DD3223ED PIV.9C rsa2048 (cert,sign)
   (4) 34798AAFE0A7565088101CC4AE31C5C8C74461CB PIV.9D rsa2048 (encr)
Your selection? 4
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0)
Key does not expire at all
Is this correct? (y/N) y
Really create? (y/N) y

sec  rsa2048/C3AFA9ED971BB365
     created: 2019-04-04  expires: never       usage: SC
     card-no: FF020001008A77C1
     trust: ultimate      validity: ultimate
ssb  rsa2048/7067860A98FCE6E1
     created: 2019-04-04  expires: never       usage: E
     card-no: FF020001008A77C1
[ultimate] (1). otto@example.net

gpg> save

Now you can use your PIV card also with gpg.


10 Helper Tools

GnuPG comes with a couple of smaller tools:


10.1 Read logs from a socket

Most of the main utilities are able to write their log files to a Unix Domain socket if configured that way. watchgnupg is a simple listener for such a socket. It ameliorates the output with a time stamp and makes sure that long lines are not interspersed with log output from other utilities. This tool is not available for Windows.

watchgnupg is commonly invoked as

watchgnupg

which is a shorthand for

watchgnupg --force $(gpgconf --list-dirs socketdir)/S.log

To watch GnuPG running with a different home directory, use

watchgnupg --homedir DIR

This starts it on the current terminal for listening on the standard logging socket (this is commonly /var/run/user/UID/gnupg/S.log or if no such user directory hierarchy exists ~/.gnupg/S.log).

watchgnupg understands these options:

--force

Delete an already existing socket file. This option is implicitly used if no socket name has been given on the command line.

--homedir DIR

If no socket name is given on the command line, pass DIR to gpgconf so that the socket for a GnuPG running with DIR has its home directory is used. Note that the environment variable GNUPGHOME is ignored by watchgnupg.

--tcp n

Instead of reading from a local socket, listen for connects on TCP port n. A Unix domain socket can optionally also be given as a second source. This option does not use a default socket name.

--time-only

Do not print the date part of the timestamp.

--verbose

Enable extra informational output.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.

Examples

$ watchgnupg --time-only

This waits for connections on the local socket (e.g. /var/run/user/1234/gnupg/S.log) and shows all log entries. To make this work the option log-file needs to be used with all modules which logs are to be shown. The suggested entry for the configuration files is:

log-file socket://

If the default socket as given above and returned by "echo $(gpgconf –list-dirs socketdir)/S.log" is not desired an arbitrary socket name can be specified, for example socket:///home/foo/bar/mysocket. For debugging purposes it is also possible to do remote logging. Take care if you use this feature because the information is send in the clear over the network. Use this syntax in the conf files:

log-file tcp://192.168.1.1:4711

You may use any port and not just 4711 as shown above; only IP addresses are supported (v4 and v6) and no host names. You need to start watchgnupg with the tcp option. Note that under Windows the registry entry HKCU\Software\GNU\GnuPG:DefaultLogFile can be used to change the default log output from stderr to whatever is given by that entry. However the only useful entry is a TCP name for remote debugging.


10.2 Verify OpenPGP signatures

gpgv is an OpenPGP signature verification tool.

This program is actually a stripped-down version of gpg which is only able to check signatures. It is somewhat smaller than the fully-blown gpg and uses a different (and simpler) way to check that the public keys used to make the signature are valid. There are no configuration files and only a few options are implemented.

gpgv assumes that all keys in the keyring are trustworthy. That does also mean that it does not check for expired or revoked keys.

If no --keyring option is given, gpgv looks for a “default” keyring named trustedkeys.kbx (preferred) or trustedkeys.gpg in the home directory of GnuPG, either the default home directory or the one set by the --homedir option or the GNUPGHOME environment variable. If any --keyring option is used, gpgv will not look for the default keyring. The --keyring option may be used multiple times and all specified keyrings will be used together.

gpgv recognizes these options:

--verbose
-v

Gives more information during processing. If used twice, the input data is listed in detail.

--quiet
-q

Try to be as quiet as possible.

--keyring file

Add file to the list of keyrings. If file begins with a tilde and a slash, these are replaced by the HOME directory. If the filename does not contain a slash, it is assumed to be in the home-directory ("~/.gnupg" if –homedir is not used).

--output file
-o file

Write output to file; to write to stdout use -. This option can be used to get the signed text from a cleartext or binary signature; it also works for detached signatures, but in that case this option is in general not useful. Note that an existing file will be overwritten.

--status-fd n

Write special status strings to the file descriptor n. See the file DETAILS in the documentation for a listing of them.

--logger-fd n

Write log output to file descriptor n and not to stderr.

--log-file file

Same as --logger-fd, except the logger data is written to file file. Use socket:// to log to socket.

--ignore-time-conflict

GnuPG normally checks that the timestamps associated with keys and signatures have plausible values. However, sometimes a signature seems to be older than the key due to clock problems. This option turns these checks into warnings.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

--weak-digest name

Treat the specified digest algorithm as weak. Signatures made over weak digests algorithms are normally rejected. This option can be supplied multiple times if multiple algorithms should be considered weak. MD5 is always considered weak, and does not need to be listed explicitly.

--enable-special-filenames

This option enables a mode in which filenames of the form -&n, where n is a non-negative decimal number, refer to the file descriptor n and not to a file with that name.

The program returns 0 if everything is fine, 1 if at least one signature was bad, and other error codes for fatal errors.

10.2.1 Examples

gpgv pgpfile
gpgv sigfile [datafile]

Verify the signature of the file. The second form is used for detached signatures, where sigfile is the detached signature (either ASCII-armored or binary) and datafile contains the signed data; if datafile is "-" the signed data is expected on stdin; if datafile is not given the name of the file holding the signed data is constructed by cutting off the extension (".asc", ".sig" or ".sign") from sigfile.

10.2.2 Environment

HOME

Used to locate the default home directory.

GNUPGHOME

If set directory used instead of "~/.gnupg".

10.2.3 FILES

~/.gnupg/trustedkeys.gpg

The default keyring with the allowed keys.

gpg(1)


10.3 Create .gnupg home directories

If GnuPG is installed on a system with existing user accounts, it is sometimes required to populate the GnuPG home directory with existing files. Especially a trustlist.txt and a keybox with some initial certificates are often desired. This script helps to do this by copying all files from /etc/skel/.gnupg to the home directories of the accounts given on the command line. It takes care not to overwrite existing GnuPG home directories.

addgnupghome is invoked by root as:

addgnupghome account1 account2 ... accountn

10.4 Modify .gnupg home directories

The gpgconf is a utility to automatically and reasonable safely query and modify configuration files in the .gnupg home directory. It is designed not to be invoked manually by the user, but automatically by graphical user interfaces (GUI).3

gpgconf provides access to the configuration of one or more components of the GnuPG system. These components correspond more or less to the programs that exist in the GnuPG framework, like GPG, GPGSM, DirMngr, etc. But this is not a strict one-to-one relationship. Not all configuration options are available through gpgconf. gpgconf provides a generic and abstract method to access the most important configuration options that can feasibly be controlled via such a mechanism.

gpgconf can be used to gather and change the options available in each component, and can also provide their default values. gpgconf will give detailed type information that can be used to restrict the user’s input without making an attempt to commit the changes.

gpgconf provides the backend of a configuration editor. The configuration editor would usually be a graphical user interface program that displays the current options, their default values, and allows the user to make changes to the options. These changes can then be made active with gpgconf again. Such a program that uses gpgconf in this way will be called GUI throughout this section.


10.4.1 Invoking gpgconf

One of the following commands must be given:

--list-components

List all components. This is the default command used if none is specified.

--check-programs

List all available backend programs and test whether they are runnable.

--list-options component

List all options of the component component.

--change-options component

Change the options of the component component.

--check-options component

Check the options for the component component.

--apply-profile file

Apply the configuration settings listed in file to the configuration files. If file has no suffix and no slashes the command first tries to read a file with the suffix .prf from the data directory (gpgconf --list-dirs datadir) before it reads the file verbatim. A profile is divided into sections using the bracketed component name. Each section then lists the option which shall go into the respective configuration file.

--apply-defaults

Update all configuration files with values taken from the global configuration file (usually /etc/gnupg/gpgconf.conf).

--list-dirs [names]

Lists the directories used by gpgconf. One directory is listed per line, and each line consists of a colon-separated list where the first field names the directory type (for example sysconfdir) and the second field contains the percent-escaped directory. Although they are not directories, the socket file names used by gpg-agent and dirmngr are printed as well. Note that the socket file names and the homedir lines are the default names and they may be overridden by command line switches. If names are given only the directories or file names specified by the list names are printed without any escaping.

--list-config [filename]

List the global configuration file in a colon separated format. If filename is given, check that file instead.

--check-config [filename]

Run a syntax check on the global configuration file. If filename is given, check that file instead.

--query-swdb package_name [version_string]

Returns the current version for package_name and if version_string is given also an indicator on whether an update is available. The actual file with the software version is automatically downloaded and checked by dirmngr. dirmngr uses a thresholds to avoid download the file too often and it does this by default only if it can be done via Tor. To force an update of that file this command can be used:

       gpg-connect-agent --dirmngr 'loadswdb --force' /bye
--reload [component]

Reload all or the given component. This is basically the same as sending a SIGHUP to the component. Components which don’t support reloading are ignored. Without component or by using "all" for component all components which are daemons are reloaded.

--launch [component]

If the component is not already running, start it. component must be a daemon. This is in general not required because the system starts these daemons as needed. However, external software making direct use of gpg-agent or dirmngr may use this command to ensure that they are started. Using "all" for component launches all components which are daemons.

--kill [component]

Kill the given component that runs as a daemon, including gpg-agent, dirmngr, and scdaemon. A component which does not run as a daemon will be ignored. Using "all" for component kills all components running as daemons. Note that as of now reload and kill have the same effect for scdaemon.

--create-socketdir

Create a directory for sockets below /run/user or /var/run/user. This is command is only required if a non default home directory is used and the /run based sockets shall be used. For the default home directory GnUPG creates a directory on the fly.

--remove-socketdir

Remove a directory created with command --create-socketdir.

The following options may be used:

-o file
--output file

Write output to file. Default is to write to stdout.

-v
--verbose

Outputs additional information while running. Specifically, this extends numerical field values by human-readable descriptions.

-q
--quiet

Try to be as quiet as possible.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

--chuid uid

Change the current user to uid which may either be a number or a name. This can be used from the root account to get information on the GnuPG environment of the specified user or to start or kill daemons. If uid is not the current UID a standard PATH is set and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This option has currently no effect on Windows.

-n
--dry-run

Do not actually change anything. This is currently only implemented for --change-options and can be used for testing purposes.

-r
--runtime

Only used together with --change-options. If one of the modified options can be changed in a running daemon process, signal the running daemon to ask it to reparse its configuration file after changing.

This means that the changes will take effect at run-time, as far as this is possible. Otherwise, they will take effect at the next start of the respective backend programs.

--status-fd n

Write special status strings to the file descriptor n. This program returns the status messages SUCCESS or FAILURE which are helpful when the caller uses a double fork approach and can’t easily get the return code of the process.


10.4.2 Format conventions

Some lines in the output of gpgconf contain a list of colon-separated fields. The following conventions apply:

  • The GUI program is required to strip off trailing newline and/or carriage return characters from the output.
  • gpgconf will never leave out fields. If a certain version provides a certain field, this field will always be present in all gpgconf versions from that time on.
  • Future versions of gpgconf might append fields to the list. New fields will always be separated from the previously last field by a colon separator. The GUI should be prepared to parse the last field it knows about up until a colon or end of line.
  • Not all fields are defined under all conditions. You are required to ignore the content of undefined fields.

There are several standard types for the content of a field:

verbatim

Some fields contain strings that are not escaped in any way. Such fields are described to be used verbatim. These fields will never contain a colon character (for obvious reasons). No de-escaping or other formatting is required to use the field content. This is for easy parsing of the output, when it is known that the content can never contain any special characters.

percent-escaped

Some fields contain strings that are described to be percent-escaped. Such strings need to be de-escaped before their content can be presented to the user. A percent-escaped string is de-escaped by replacing all occurrences of %XY by the byte that has the hexadecimal value XY. X and Y are from the set 0-9a-f.

localized

Some fields contain strings that are described to be localized. Such strings are translated to the active language and formatted in the active character set.

unsigned number

Some fields contain an unsigned number. This number will always fit into a 32-bit unsigned integer variable. The number may be followed by a space, followed by a human readable description of that value (if the verbose option is used). You should ignore everything in the field that follows the number.

signed number

Some fields contain a signed number. This number will always fit into a 32-bit signed integer variable. The number may be followed by a space, followed by a human readable description of that value (if the verbose option is used). You should ignore everything in the field that follows the number.

boolean value

Some fields contain a boolean value. This is a number with either the value 0 or 1. The number may be followed by a space, followed by a human readable description of that value (if the verbose option is used). You should ignore everything in the field that follows the number; checking just the first character is sufficient in this case.

option

Some fields contain an option argument. The format of an option argument depends on the type of the option and on some flags:

no argument

The simplest case is that the option does not take an argument at all (type 0). Then the option argument is an unsigned number that specifies how often the option occurs. If the list flag is not set, then the only valid number is 1. Options that do not take an argument never have the default or optional arg flag set.

number

If the option takes a number argument (alt-type is 2 or 3), and it can only occur once (list flag is not set), then the option argument is either empty (only allowed if the argument is optional), or it is a number. A number is a string that begins with an optional minus character, followed by one or more digits. The number must fit into an integer variable (unsigned or signed, depending on alt-type).

number list

If the option takes a number argument and it can occur more than once, then the option argument is either empty, or it is a comma-separated list of numbers as described above.

string

If the option takes a string argument (alt-type is 1), and it can only occur once (list flag is not set) then the option argument is either empty (only allowed if the argument is optional), or it starts with a double quote character (") followed by a percent-escaped string that is the argument value. Note that there is only a leading double quote character, no trailing one. The double quote character is only needed to be able to differentiate between no value and the empty string as value.

string list

If the option takes a string argument and it can occur more than once, then the option argument is either empty, or it is a comma-separated list of string arguments as described above.

The active language and character set are currently determined from the locale environment of the gpgconf program.


10.4.3 Listing components

The command --list-components will list all components that can be configured with gpgconf. Usually, one component will correspond to one GnuPG-related program and contain the options of that program’s configuration file that can be modified using gpgconf. However, this is not necessarily the case. A component might also be a group of selected options from several programs, or contain entirely virtual options that have a special effect rather than changing exactly one option in one configuration file.

A component is a set of configuration options that semantically belong together. Furthermore, several changes to a component can be made in an atomic way with a single operation. The GUI could for example provide a menu with one entry for each component, or a window with one tabulator sheet per component.

The command --list-components lists all available components, one per line. The format of each line is:

name:description:pgmname:

name

This field contains a name tag of the component. The name tag is used to specify the component in all communication with gpgconf. The name tag is to be used verbatim. It is thus not in any escaped format.

description

The string in this field contains a human-readable description of the component. It can be displayed to the user of the GUI for informational purposes. It is percent-escaped and localized.

pgmname

The string in this field contains the absolute name of the program’s file. It can be used to unambiguously invoke that program. It is percent-escaped.

Example:

$ gpgconf --list-components
gpg:GPG for OpenPGP:/usr/local/bin/gpg2:
gpg-agent:GPG Agent:/usr/local/bin/gpg-agent:
scdaemon:Smartcard Daemon:/usr/local/bin/scdaemon:
gpgsm:GPG for S/MIME:/usr/local/bin/gpgsm:
dirmngr:Directory Manager:/usr/local/bin/dirmngr:

10.4.4 Checking programs

The command --check-programs is similar to --list-components but works on backend programs and not on components. It runs each program to test whether it is installed and runnable. This also includes a syntax check of all config file options of the program.

The command --check-programs lists all available programs, one per line. The format of each line is:

name:description:pgmname:avail:okay:cfgfile:line:error:

name

This field contains a name tag of the program which is identical to the name of the component. The name tag is to be used verbatim. It is thus not in any escaped format. This field may be empty to indicate a continuation of error descriptions for the last name. The description and pgmname fields are then also empty.

description

The string in this field contains a human-readable description of the component. It can be displayed to the user of the GUI for informational purposes. It is percent-escaped and localized.

pgmname

The string in this field contains the absolute name of the program’s file. It can be used to unambiguously invoke that program. It is percent-escaped.

avail

The boolean value in this field indicates whether the program is installed and runnable.

okay

The boolean value in this field indicates whether the program’s config file is syntactically okay.

cfgfile

If an error occurred in the configuration file (as indicated by a false value in the field okay), this field has the name of the failing configuration file. It is percent-escaped.

line

If an error occurred in the configuration file, this field has the line number of the failing statement in the configuration file. It is an unsigned number.

error

If an error occurred in the configuration file, this field has the error text of the failing statement in the configuration file. It is percent-escaped and localized.

In the following example the dirmngr is not runnable and the configuration file of scdaemon is not okay.

$ gpgconf --check-programs
gpg:GPG for OpenPGP:/usr/local/bin/gpg2:1:1:
gpg-agent:GPG Agent:/usr/local/bin/gpg-agent:1:1:
scdaemon:Smartcard Daemon:/usr/local/bin/scdaemon:1:0:
gpgsm:GPG for S/MIME:/usr/local/bin/gpgsm:1:1:
dirmngr:Directory Manager:/usr/local/bin/dirmngr:0:0:

The command --check-options component will verify the configuration file in the same manner as --check-programs, but only for the component component.


10.4.5 Listing options

Every component contains one or more options. Options may be gathered into option groups to allow the GUI to give visual hints to the user about which options are related.

The command --list-options component lists all options (and the groups they belong to) in the component component, one per line. component must be the string in the field name in the output of the --list-components command.

There is one line for each option and each group. First come all options that are not in any group. Then comes a line describing a group. Then come all options that belong into each group. Then comes the next group and so on. There does not need to be any group (and in this case the output will stop after the last non-grouped option).

The format of each line is:

name:flags:level:description:type:alt-type:argname:default:argdef:value

name

This field contains a name tag for the group or option. The name tag is used to specify the group or option in all communication with gpgconf. The name tag is to be used verbatim. It is thus not in any escaped format.

flags

The flags field contains an unsigned number. Its value is the OR-wise combination of the following flag values:

group (1)

If this flag is set, this is a line describing a group and not an option.

The following flag values are only defined for options (that is, if the group flag is not used).

optional arg (2)

If this flag is set, the argument is optional. This is never set for type 0 (none) options.

list (4)

If this flag is set, the option can be given multiple times.

runtime (8)

If this flag is set, the option can be changed at runtime.

default (16)

If this flag is set, a default value is available.

default desc (32)

If this flag is set, a (runtime) default is available. This and the default flag are mutually exclusive.

no arg desc (64)

If this flag is set, and the optional arg flag is set, then the option has a special meaning if no argument is given.

no change (128)

If this flag is set, gpgconf ignores requests to change the value. GUI frontends should grey out this option. Note, that manual changes of the configuration files are still possible.

level

This field is defined for options and for groups. It contains an unsigned number that specifies the expert level under which this group or option should be displayed. The following expert levels are defined for options (they have analogous meaning for groups):

basic (0)

This option should always be offered to the user.

advanced (1)

This option may be offered to advanced users.

expert (2)

This option should only be offered to expert users.

invisible (3)

This option should normally never be displayed, not even to expert users.

internal (4)

This option is for internal use only. Ignore it.

The level of a group will always be the lowest level of all options it contains.

description

This field is defined for options and groups. The string in this field contains a human-readable description of the option or group. It can be displayed to the user of the GUI for informational purposes. It is percent-escaped and localized.

type

This field is only defined for options. It contains an unsigned number that specifies the type of the option’s argument, if any. The following types are defined:

Basic types:

none (0)

No argument allowed.

string (1)

An unformatted string.

int32 (2)

A signed number.

uint32 (3)

An unsigned number.

Complex types:

pathname (32)

A string that describes the pathname of a file. The file does not necessarily need to exist.

ldap server (33)

A string that describes an LDAP server in the format:

hostname:port:username:password:base_dn

key fingerprint (34)

A string with a 40 digit fingerprint specifying a certificate.

pub key (35)

A string that describes a certificate by user ID, key ID or fingerprint.

sec key (36)

A string that describes a certificate with a key by user ID, key ID or fingerprint.

alias list (37)

A string that describes an alias list, like the one used with gpg’s group option. The list consists of a key, an equal sign and space separated values.

More types will be added in the future. Please see the alt-type field for information on how to cope with unknown types.

alt-type

This field is identical to type, except that only the types 0 to 31 are allowed. The GUI is expected to present the user the option in the format specified by type. But if the argument type type is not supported by the GUI, it can still display the option in the more generic basic type alt-type. The GUI must support all the defined basic types to be able to display all options. More basic types may be added in future versions. If the GUI encounters a basic type it doesn’t support, it should report an error and abort the operation.

argname

This field is only defined for options with an argument type type that is not 0. In this case it may contain a percent-escaped and localized string that gives a short name for the argument. The field may also be empty, though, in which case a short name is not known.

default

This field is defined only for options for which the default or default desc flag is set. If the default flag is set, its format is that of an option argument (see Format conventions, for details). If the default value is empty, then no default is known. Otherwise, the value specifies the default value for this option. If the default desc flag is set, the field is either empty or contains a description of the effect if the option is not given.

argdef

This field is defined only for options for which the optional arg flag is set. If the no arg desc flag is not set, its format is that of an option argument (see Format conventions, for details). If the default value is empty, then no default is known. Otherwise, the value specifies the default argument for this option. If the no arg desc flag is set, the field is either empty or contains a description of the effect of this option if no argument is given.

value

This field is defined only for options. Its format is that of an option argument. If it is empty, then the option is not explicitly set in the current configuration, and the default applies (if any). Otherwise, it contains the current value of the option. Note that this field is also meaningful if the option itself does not take a real argument (in this case, it contains the number of times the option appears).


10.4.6 Changing options

The command --change-options component will attempt to change the options of the component component to the specified values. component must be the string in the field name in the output of the --list-components command. You have to provide the options that shall be changed in the following format on standard input:

name:flags:new-value

name

This is the name of the option to change. name must be the string in the field name in the output of the --list-options command.

flags

The flags field contains an unsigned number. Its value is the OR-wise combination of the following flag values:

default (16)

If this flag is set, the option is deleted and the default value is used instead (if applicable).

new-value

The new value for the option. This field is only defined if the default flag is not set. The format is that of an option argument. If it is empty (or the field is omitted), the default argument is used (only allowed if the argument is optional for this option). Otherwise, the option will be set to the specified value.

The output of the command is the same as that of --check-options for the modified configuration file.

Examples:

To set the force option, which is of basic type none (0):

$ echo 'force:0:1' | gpgconf --change-options dirmngr

To delete the force option:

$ echo 'force:16:' | gpgconf --change-options dirmngr

The --runtime option can influence when the changes take effect.


10.4.7 Listing global options

Sometimes it is useful for applications to look at the global options file gpgconf.conf. The colon separated listing format is record oriented and uses the first field to identify the record type:

k

This describes a key record to start the definition of a new ruleset for a user/group. The format of a key record is:

k:user:group:

user

This is the user field of the key. It is percent escaped. See the definition of the gpgconf.conf format for details.

group

This is the group field of the key. It is percent escaped.

r

This describes a rule record. All rule records up to the next key record make up a rule set for that key. The format of a rule record is:

r:::component:option:flag:value:

component

This is the component part of a rule. It is a plain string.

option

This is the option part of a rule. It is a plain string.

flag

This is the flags part of a rule. There may be only one flag per rule but by using the same component and option, several flags may be assigned to an option. It is a plain string.

value

This is the optional value for the option. It is a percent escaped string with a single quotation mark to indicate a string. The quotation mark is only required to distinguish between no value specified and an empty string.

Unknown record types should be ignored. Note that there is intentionally no feature to change the global option file through gpgconf.


10.4.8 Get and compare software versions.

The GnuPG Project operates a server to query the current versions of software packages related to GnuPG. gpgconf can be used to access this online database. To allow for offline operations, this feature works by having dirmngr download a file from https://versions.gnupg.org, checking the signature of that file and storing the file in the GnuPG home directory. If gpgconf is used and dirmngr is running, it may ask dirmngr to refresh that file before itself uses the file.

The command --query-swdb returns information for the given package in a colon delimited format:

name

This is the name of the package as requested. Note that "gnupg" is a special name which is replaced by the actual package implementing this version of GnuPG. For this name it is also not required to specify a version because gpgconf takes its own version in this case.

iversion

The currently installed version or an empty string. The value is taken from the command line argument but may be provided by gpg if not given.

status

The status of the software package according to this table:

-

No information available. This is either because no current version has been specified or due to an error.

?

The given name is not known in the online database.

u

An update of the software is available.

c

The installed version of the software is current.

n

The installed version is already newer than the released version.

urgency

If the value (the empty string should be considered as zero) is greater than zero an important update is available.

error

This returns an gpg-error error code to distinguish between various failure modes.

filedate

This gives the date of the file with the version numbers in standard ISO format (yyyymmddThhmmss). The date has been extracted by dirmngr from the signature of the file.

verified

This gives the date in ISO format the file was downloaded. This value can be used to evaluate the freshness of the information.

version

This returns the version string for the requested software from the file.

reldate

This returns the release date in ISO format.

size

This returns the size of the package as decimal number of bytes.

hash

This returns a hexified SHA-2 hash of the package.

More fields may be added in future to the output.


10.4.9 Files used by gpgconf

/etc/gnupg/gpgconf.conf

If this file exists, it is processed as a global configuration file. A commented example can be found in the examples directory of the distribution.

GNUPGHOME/swdb.lst

A file with current software versions. dirmngr creates this file on demand from an online resource.


10.5 Run gpgconf for all users

This script is a wrapper around gpgconf to run it with the command --apply-defaults for all real users with an existing GnuPG home directory. Admins might want to use this script to update he GnuPG configuration files for all users after /etc/gnupg/gpgconf.conf has been changed. This allows enforcing certain policies for all users. Note, that this is not a bulletproof way to force a user to use certain options. A user may always directly edit the configuration files and bypass gpgconf.

applygnupgdefaults is invoked by root as:

applygnupgdefaults

10.6 Put a passphrase into the cache

The gpg-preset-passphrase is a utility to seed the internal cache of a running gpg-agent with passphrases. It is mainly useful for unattended machines, where the usual pinentry tool may not be used and the passphrases for the to be used keys are given at machine startup.

This program works with GnuPG 2 and later. GnuPG 1.x is not supported.

Passphrases set with this utility don’t expire unless the --forget option is used to explicitly clear them from the cache — or gpg-agent is either restarted or reloaded (by sending a SIGHUP to it). Note that the maximum cache time as set with --max-cache-ttl is still honored. It is necessary to allow this passphrase presetting by starting gpg-agent with the --allow-preset-passphrase.


10.6.1 List of all commands and options

gpg-preset-passphrase is invoked this way:

gpg-preset-passphrase [options] [command] cacheid

cacheid is either a 40 character keygrip of hexadecimal characters identifying the key for which the passphrase should be set or cleared. The keygrip is listed along with the key when running the command: gpgsm --with-keygrip --list-secret-keys. Alternatively an arbitrary string may be used to identify a passphrase; it is suggested that such a string is prefixed with the name of the application (e.g foo:12346). Scripts should always use the option --with-colons, which provides the keygrip in a "grp" line (cf. doc/DETAILS)/

One of the following command options must be given:

--preset

Preset a passphrase. This is what you usually will use. gpg-preset-passphrase will then read the passphrase from stdin.

--forget

Flush the passphrase for the given cache ID from the cache.

The following additional options may be used:

-v
--verbose

Output additional information while running.

-P string
--passphrase string

Instead of reading the passphrase from stdin, use the supplied string as passphrase. Note that this makes the passphrase visible for other users.


10.7 Communicate with a running agent

The gpg-connect-agent is a utility to communicate with a running gpg-agent. It is useful to check out the commands gpg-agent provides using the Assuan interface. It might also be useful for scripting simple applications. Input is expected at stdin and output gets printed to stdout.

It is very similar to running gpg-agent in server mode; but here we connect to a running instance.


10.7.1 List of all options

gpg-connect-agent is invoked this way:

gpg-connect-agent [options] [commands]

The following options may be used:

--dirmngr

Connect to a running directory manager (keyserver client) instead of to the gpg-agent. If a dirmngr is not running, start it.

--keyboxd

Connect to a running keybox daemon instead of to the gpg-agent. If a keyboxd is not running, start it.

-S
--raw-socket name

Connect to socket name assuming this is an Assuan style server. Do not run any special initializations or environment checks. This may be used to directly connect to any Assuan style socket server.

-E
--exec

Take the rest of the command line as a program and it’s arguments and execute it as an Assuan server. Here is how you would run gpgsm:

 gpg-connect-agent --exec gpgsm --server

Note that you may not use options on the command line in this case.

-v
--verbose

Output additional information while running.

-q
--quiet

Try to be as quiet as possible.

--homedir dir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ~/.gnupg. It is only recognized when given on the command line. It also overrides any home directory stated through the environment variable GNUPGHOME or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named gpgconf.ctl in the same directory as the tool gpgconf.exe. The root of the installation is then that directory; or, if gpgconf.exe has been installed directly below a directory named bin, its parent directory. You also need to make sure that the following directories exist and are writable: ROOT/home for the GnuPG home and ROOT/nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/var/cache/gnupg for internal cache files.

--chuid uid

Change the current user to uid which may either be a number or a name. This can be used from the root account to run gpg-connect-agent for another user. If uid is not the current UID a standard PATH is set and the envvar GNUPGHOME is unset. To override the latter the option --homedir can be used. This option has only an effect when used on the command line. This option has currently no effect at all on Windows.

--no-ext-connect

When using -S or --exec, gpg-connect-agent connects to the Assuan server in extended mode to allow descriptor passing. This option makes it use the old mode.

--no-autostart

Do not start the gpg-agent or the dirmngr if it has not yet been started.

--no-history

In interactive mode the command line history is usually saved and restored to and from a file below the GnuPG home directory. This option inhibits the use of that file.

--agent-program file

Specify the agent program to be started if none is running. The default value is determined by running gpgconf with the option --list-dirs. Note that the pipe symbol (|) is used for a regression test suite hack and may thus not be used in the file name.

--dirmngr-program file

Specify the directory manager (keyserver client) program to be started if none is running. This has only an effect if used together with the option --dirmngr.

--keyboxd-program file

Specify the keybox daemon program to be started if none is running. This has only an effect if used together with the option --keyboxd.

-r file
--run file

Run the commands from file at startup and then continue with the regular input method. Note, that commands given on the command line are executed after this file.

-s
--subst

Run the command /subst at startup.

--hex

Print data lines in a hex format and the ASCII representation of non-control characters.

--decode

Decode data lines. That is to remove percent escapes but make sure that a new line always starts with a D and a space.


10.7.2 Control commands

While reading Assuan commands, gpg-agent also allows a few special commands to control its operation. These control commands all start with a slash (/).

/echo args

Just print args.

/let name value

Set the variable name to value. Variables are only substituted on the input if the /subst has been used. Variables are referenced by prefixing the name with a dollar sign and optionally include the name in curly braces. The rules for a valid name are identically to those of the standard bourne shell. This is not yet enforced but may be in the future. When used with curly braces no leading or trailing white space is allowed.

If a variable is not found, it is searched in the environment and if found copied to the table of variables.

Variable functions are available: The name of the function must be followed by at least one space and the at least one argument. The following functions are available:

get

Return a value described by the argument. Available arguments are:

cwd

The current working directory.

homedir

The gnupg homedir.

sysconfdir

GnuPG’s system configuration directory.

bindir

GnuPG’s binary directory.

libdir

GnuPG’s library directory.

libexecdir

GnuPG’s library directory for executable files.

datadir

GnuPG’s data directory.

serverpid

The PID of the current server. Command /serverpid must have been given to return a useful value.

unescape args

Remove C-style escapes from args. Note that \0 and \x00 terminate the returned string implicitly. The string to be converted are the entire arguments right behind the delimiting space of the function name.

unpercent args
unpercent+ args

Remove percent style escaping from args. Note that %00 terminates the string implicitly. The string to be converted are the entire arguments right behind the delimiting space of the function name. unpercent+ also maps plus signs to a spaces.

percent args
percent+ args

Escape the args using percent style escaping. Tabs, formfeeds, linefeeds, carriage returns and colons are escaped. percent+ also maps spaces to plus signs.

errcode arg
errsource arg
errstring arg

Assume arg is an integer and evaluate it using strtol. Return the gpg-error error code, error source or a formatted string with the error code and error source.

+
-
*
/
%

Evaluate all arguments as long integers using strtol and apply this operator. A division by zero yields an empty string.

!
|
&

Evaluate all arguments as long integers using strtol and apply the logical operators NOT, OR or AND. The NOT operator works on the last argument only.

/definq name var

Use content of the variable var for inquiries with name. name may be an asterisk (*) to match any inquiry.

/definqfile name file

Use content of file for inquiries with name. name may be an asterisk (*) to match any inquiry.

/definqprog name prog

Run prog for inquiries matching name and pass the entire line to it as command line arguments.

/datafile name

Write all data lines from the server to the file name. The file is opened for writing and created if it does not exists. An existing file is first truncated to 0. The data written to the file fully decoded. Using a single dash for name writes to stdout. The file is kept open until a new file is set using this command or this command is used without an argument.

/showdef

Print all definitions

/cleardef

Delete all definitions

/sendfd file mode

Open file in mode (which needs to be a valid fopen mode string) and send the file descriptor to the server. This is usually followed by a command like INPUT FD to set the input source for other commands.

/recvfd

Not yet implemented.

/open var file [mode]

Open file and assign the file descriptor to var. Warning: This command is experimental and might change in future versions.

/close fd

Close the file descriptor fd. Warning: This command is experimental and might change in future versions.

/showopen

Show a list of open files.

/serverpid

Send the Assuan command GETINFO pid to the server and store the returned PID for internal purposes.

/sleep

Sleep for a second.

/hex
/nohex

Same as the command line option --hex.

/decode
/nodecode

Same as the command line option --decode.

/subst
/nosubst

Enable and disable variable substitution. It defaults to disabled unless the command line option --subst has been used. If /subst as been enabled once, leading whitespace is removed from input lines which makes scripts easier to read.

/while condition
/end

These commands provide a way for executing loops. All lines between the while and the corresponding end are executed as long as the evaluation of condition yields a non-zero value or is the string true or yes. The evaluation is done by passing condition to the strtol function. Example:

  /subst
  /let i 3
  /while $i
    /echo loop counter is $i
    /let i ${- $i 1}
  /end
/if condition
/end

These commands provide a way for conditional execution. All lines between the if and the corresponding end are executed only if the evaluation of condition yields a non-zero value or is the string true or yes. The evaluation is done by passing condition to the strtol function.

/run file

Run commands from file.

/history --clear

Clear the command history.

/bye

Terminate the connection and the program.

/help

Print a list of available control commands.


10.8 The Dirmngr Client Tool

The dirmngr-client is a simple tool to contact a running dirmngr and test whether a certificate has been revoked — either by being listed in the corresponding CRL or by running the OCSP protocol. If no dirmngr is running, a new instances will be started but this is in general not a good idea due to the huge performance overhead.

The usual way to run this tool is either:

dirmngr-client acert

or

dirmngr-client <acert

Where acert is one DER encoded (binary) X.509 certificates to be tested. The return value of this command is

0

The certificate under question is valid; i.e. there is a valid CRL available and it is not listed there or the OCSP request returned that that certificate is valid.

1

The certificate has been revoked

2 (and other values)

There was a problem checking the revocation state of the certificate. A message to stderr has given more detailed information. Most likely this is due to a missing or expired CRL or due to a network problem.

dirmngr-client may be called with the following options:

--version

Print the program version and licensing information. Note that you cannot abbreviate this command.

--help, -h

Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command.

--quiet, -q

Make the output extra brief by suppressing any informational messages.

-v
--verbose

Outputs additional information while running. You can increase the verbosity by giving several verbose commands to DIRMNGR, such as ‘-vv’.

--pem

Assume that the given certificate is in PEM (armored) format.

--ocsp

Do the check using the OCSP protocol and ignore any CRLs.

--force-default-responder

When checking using the OCSP protocol, force the use of the default OCSP responder. That is not to use the Reponder as given by the certificate.

--ping

Check whether the dirmngr daemon is up and running.

--cache-cert

Put the given certificate into the cache of a running dirmngr. This is mainly useful for debugging.

--validate

Validate the given certificate using dirmngr’s internal validation code. This is mainly useful for debugging.

--load-crl

This command expects a list of filenames with DER encoded CRL files. With the option --url URLs are expected in place of filenames and they are loaded directly from the given location. All CRLs will be validated and then loaded into dirmngr’s cache.

--lookup

Take the remaining arguments and run a lookup command on each of them. The results are Base-64 encoded outputs (without header lines). This may be used to retrieve certificates from a server. However the output format is not very well suited if more than one certificate is returned.

--url
-u

Modify the lookup and load-crl commands to take an URL.

--local
-l

Let the lookup command only search the local cache.

--squid-mode

Run DIRMNGR-CLIENT in a mode suitable as a helper program for Squid’s external_acl_type option.


10.9 Parse a mail message into an annotated format

The gpgparsemail is a utility currently only useful for debugging. Run it with --help for usage information.


10.10 Encrypt or sign files into an archive

gpgtar encrypts or signs files into an archive. It is an gpg-ized tar using the same format as used by PGP’s PGP Zip.

gpgtar is invoked this way:

gpgtar [options] filename1 [filename2, ...] directory [directory2, ...]

gpgtar understands these options:

--create

Put given files and directories into a vanilla “ustar” archive.

--extract

Extract all files from a vanilla “ustar” archive.

--encrypt
-e

Encrypt given files and directories into an archive. This option may be combined with option --symmetric for an archive that may be decrypted via a secret key or a passphrase.

--decrypt
-d

Extract all files from an encrypted archive.

--sign
-s

Make a signed archive from the given files and directories. This can be combined with option --encrypt to create a signed and then encrypted archive.

--list-archive
-t

List the contents of the specified archive.

--symmetric
-c

Encrypt with a symmetric cipher using a passphrase. The default symmetric cipher used is AES-128, but may be chosen with the --cipher-algo option to gpg.

--recipient user
-r user

Encrypt for user id user. For details see gpg.

--local-user user
-u user

Use user as the key to sign with. For details see gpg.

--output file
-o file

Write the archive to the specified file file.

--verbose
-v

Enable extra informational output.

--quiet
-q

Try to be as quiet as possible.

--skip-crypto

Skip all crypto operations and create or extract vanilla “ustar” archives.

--dry-run

Do not actually output the extracted files.

--directory dir
-C dir

Extract the files into the directory dir. The default is to take the directory name from the input filename. If no input filename is known a directory named GPGARCH is used. For tarball creation, switch to directory dir before performing any operations.

--files-from file
-T file

Take the file names to work from the file file; one file per line.

--null

Modify option --files-from to use a binary nul instead of a linefeed to separate file names.

--utf8-strings

Assume that the file names read by --files-from are UTF-8 encoded. This option has an effect only on Windows where the active code page is otherwise assumed.

--openpgp

This option has no effect because OpenPGP encryption and signing is the default.

--cms

This option is reserved and shall not be used. It will eventually be used to encrypt or sign using the CMS protocol; but that is not yet implemented.

--set-filename file

Use the last component of file as the output directory. The default is to take the directory name from the input filename. If no input filename is known a directory named GPGARCH is used. This option is deprecated in favor of option --directory.

--gpg gpgcmd

Use the specified command gpgcmd instead of gpg.

--gpg-args args

Pass the specified extra options to gpg.

--tar-args args

Assume args are standard options of the command tar and parse them. The only supported tar options are "–directory", "–files-from", and "–null" This is an obsolete options because those supported tar options can also be given directly.

--tar command

This is a dummy option for backward compatibility.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.

The program returns 0 if everything was fine, 1 otherwise.

Some examples:

Encrypt the contents of directory mydocs for user Bob to file test1:

gpgtar --encrypt --output test1 -r Bob mydocs

List the contents of archive test1:

gpgtar --list-archive test1

10.11 Check a passphrase on stdin against the patternfile

gpg-check-pattern checks a passphrase given on stdin against a specified pattern file.

The pattern file is line based with comment lines beginning on the first position with a #. Empty lines and lines with only white spaces are ignored. The actual pattern lines may either be verbatim string pattern and match as they are (trailing spaces are ignored) or extended regular expressions indicated by a / or !/ in the first column and terminated by another / or end of line. If a regular expression starts with !/ the match result is reversed. By default all comparisons are case insensitive.

Tag lines may be used to further control the operation of this tool. The currently defined tags are:

[icase]

Switch to case insensitive comparison for all further patterns. This is the default.

[case]

Switch to case sensitive comparison for all further patterns.

[reject]

Switch to reject mode. This is the default mode.

[accept]

Switch to accept mode.

In the future more tags may be introduced and thus it is advisable not to start a plain pattern string with an open bracket. The tags must be given verbatim on the line with no spaces to the left or any non white space characters to the right.

In reject mode the program exits on the first match with an exit code of 1 (failure). If at the end of the pattern list the reject mode is still active the program exits with code 0 (success).

In accept mode blocks of patterns are used. A block starts at the next pattern after an "accept" tag and ends with the last pattern before the next "accept" or "reject" tag or at the end of the pattern list. If all patterns in a block match the program exits with an exit code of 0 (success). If any pattern in a block do not match the next pattern block is evaluated. If at the end of the pattern list the accept mode is still active the program exits with code 1 (failure).

--verbose

Enable extra informational output.

--check

Run only a syntax check on the patternfile.

--null

Input is expected to be null delimited.


11 Web Key Service

GnuPG comes with tools used to maintain and access a Web Key Directory.


11.1 Send requests via WKS

The gpg-wks-client is used to send requests to a Web Key Service provider. This is usually done to upload a key into a Web Key Directory.

With the --supported command the caller can test whether a site supports the Web Key Service. The argument is an arbitrary address in the to be tested domain. For example foo@example.net. The command returns success if the Web Key Service is supported. The operation is silent; to get diagnostic output use the option --verbose. See option --with-colons for a variant of this command.

With the --check command the caller can test whether a key exists for a supplied mail address. The command returns success if a key is available.

The --create command is used to send a request for publication in the Web Key Directory. The arguments are the fingerprint of the key and the user id to publish. The output from the command is a properly formatted mail with all standard headers. This mail can be fed to sendmail(8) or any other tool to actually send that mail. If sendmail(8) is installed the option --send can be used to directly send the created request. If the provider request a ’mailbox-only’ user id and no such user id is found, gpg-wks-client will try an additional user id.

The --receive and --read commands are used to process confirmation mails as send from the service provider. The former expects an encrypted MIME messages, the latter an already decrypted MIME message. The result of these commands are another mail which can be send in the same way as the mail created with --create.

The command --install-key manually installs a key into a local directory (see option -C) reflecting the structure of a WKD. The arguments are a file with the keyblock and the user-id to install. If the first argument resembles a fingerprint the key is taken from the current keyring; to force the use of a file, prefix the first argument with "./". If no arguments are given the parameters are read from stdin; the expected format are lines with the fingerprint and the mailbox separated by a space. The command --remove-key removes a key from that directory, its only argument is a user-id.

The command --print-wkd-hash prints the WKD user-id identifiers and the corresponding mailboxes from the user-ids given on the command line or via stdin (one user-id per line).

The command --print-wkd-url prints the URLs used to fetch the key for the given user-ids from WKD. The meanwhile preferred format with sub-domains is used here.

gpg-wks-client understands these options:

--send

Directly send created mails using the sendmail command. Requires installation of that command.

--with-colons

This option has currently only an effect on the --supported command. If it is used all arguments on the command line are taken as domain names and tested for WKD support. The output format is one line per domain with colon delimited fields. The currently specified fields are (future versions may specify additional fields):

1 - domain

This is the domain name. Although quoting is not required for valid domain names this field is specified to be quoted in standard C manner.

2 - WKD

If the value is true the domain supports the Web Key Directory.

3 - WKS

If the value is true the domain supports the Web Key Service protocol to upload keys to the directory.

4 - error-code

This may contain an gpg-error code to describe certain failures. Use ‘gpg-error CODE’ to explain the code.

5 - protocol-version

The minimum protocol version supported by the server.

6 - auth-submit

The auth-submit flag from the policy file of the server.

7 - mailbox-only

The mailbox-only flag from the policy file of the server.

--output file
-o

Write the created mail to file instead of stdout. Note that the value - for file is the same as writing to stdout.

--status-fd n

Write special status strings to the file descriptor n. This program returns only the status messages SUCCESS or FAILURE which are helpful when the caller uses a double fork approach and can’t easily get the return code of the process.

-C dir
--directory dir

Use dir as top level directory for the commands --install-key and --remove-key. The default is openpgpkey.

--verbose

Enable extra informational output.

--quiet

Disable almost all informational output.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.


11.2 Provide the Web Key Service

The gpg-wks-server is a server side implementation of the Web Key Service. It receives requests for publication, sends confirmation requests, receives confirmations, and published the key. It also has features to ease the setup and maintenance of a Web Key Directory.

When used with the command --receive a single Web Key Service mail is processed. Commonly this command is used with the option --send to directly send the created mails back. See below for an installation example.

The command --cron is used for regular cleanup tasks. For example non-confirmed requested should be removed after their expire time. It is best to run this command once a day from a cronjob.

The command --list-domains prints all configured domains. Further it creates missing directories for the configuration and prints warnings pertaining to problems in the configuration.

The command --check-key (or just --check) checks whether a key with the given user-id is installed. The process returns success in this case; to also print a diagnostic use the option -v. If the key is not installed a diagnostic is printed and the process returns failure; to suppress the diagnostic, use option -q. More than one user-id can be given; see also option with-file.

The command --install-key manually installs a key into the WKD. The arguments are a file with the keyblock and the user-id to install. If the first argument resembles a fingerprint the key is taken from the current keyring; to force the use of a file, prefix the first argument with "./". If no arguments are given the parameters are read from stdin; the expected format are lines with the fingerprint and the mailbox separated by a space.

The command --remove-key uninstalls a key from the WKD. The process returns success in this case; to also print a diagnostic, use option -v. If the key is not installed a diagnostic is printed and the process returns failure; to suppress the diagnostic, use option -q.

The command --revoke-key is not yet functional.

gpg-wks-server understands these options:

-C dir
--directory dir

Use dir as top level directory for domains. The default is /var/lib/gnupg/wks.

--from mailaddr

Use mailaddr as the default sender address.

--header name=value

Add the mail header "name: value" to all outgoing mails.

--send

Directly send created mails using the sendmail command. Requires installation of that command.

-o file
--output file

Write the created mail also to file. Note that the value - for file would write it to stdout.

--with-dir

When used with the command --list-domains print for each installed domain the domain name and its directory name.

--with-file

When used with the command --check-key print for each user-id, the address, ’i’ for installed key or ’n’ for not installed key, and the filename.

--verbose

Enable extra informational output.

--quiet

Disable almost all informational output.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.

Examples

The Web Key Service requires a working directory to store keys pending for publication. As root create a working directory:

  # mkdir /var/lib/gnupg/wks
  # chown webkey:webkey /var/lib/gnupg/wks
  # chmod 2750 /var/lib/gnupg/wks

Then under your webkey account create directories for all your domains. Here we do it for "example.net":

  $ mkdir /var/lib/gnupg/wks/example.net

Finally run

  $ gpg-wks-server --list-domains

to create the required sub-directories with the permissions set correctly. For each domain a submission address needs to be configured. All service mails are directed to that address. It can be the same address for all configured domains, for example:

  $ cd /var/lib/gnupg/wks/example.net
  $ echo key-submission@example.net >submission-address

The protocol requires that the key to be published is sent with an encrypted mail to the service. Thus you need to create a key for the submission address:

  $ gpg --batch --passphrase '' --quick-gen-key key-submission@example.net
  $ gpg -K key-submission@example.net

The output of the last command looks similar to this:

  sec   rsa3072 2016-08-30 [SC]
        C0FCF8642D830C53246211400346653590B3795B
  uid           [ultimate] key-submission@example.net
                bxzcxpxk8h87z1k7bzk86xn5aj47intu@example.net
  ssb   rsa3072 2016-08-30 [E]

Take the fingerprint from that output and manually publish the key:

  $ gpg-wks-server --install-key C0FCF8642D830C53246211400346653590B3795B \
  >                key-submission@example.net

Finally that submission address needs to be redirected to a script running gpg-wks-server. The procmail command can be used for this: Redirect the submission address to the user "webkey" and put this into webkey’s .procmailrc:

:0
* !^From: webkey@example.net
* !^X-WKS-Loop: webkey.example.net
|gpg-wks-server -v --receive \
     --header X-WKS-Loop=webkey.example.net \
     --from webkey@example.net --send

12 How to do certain things

This is a collection of small howto documents.


12.1 Creating a TLS server certificate

Here is a brief run up on how to create a server certificate. It has actually been done this way to get a certificate from CAcert to be used on a real server. It has only been tested with this CA, but there shouldn’t be any problem to run this against any other CA.

We start by generating an X.509 certificate signing request. As there is no need for a configuration file, you may simply enter:

  $ gpgsm --generate-key >example.com.cert-req.pem
  Please select what kind of key you want:
     (1) RSA
     (2) Existing key
     (3) Existing key from card
  Your selection? 1

I opted for creating a new RSA key. The other option is to use an already existing key, by selecting 2 and entering the so-called keygrip. Running the command ‘gpgsm --dump-secret-key USERID’ shows you this keygrip. Using 3 offers another menu to create a certificate directly from a smart card based key.

Let’s continue:

  What keysize do you want? (3072)
  Requested keysize is 3072 bits

Hitting enter chooses the default RSA key size of 3072 bits. Keys smaller than 2048 bits are too weak on the modern Internet. If you choose a larger (stronger) key, your server will need to do more work.

  Possible actions for a RSA key:
     (1) sign, encrypt
     (2) sign
     (3) encrypt
  Your selection? 1

Selecting “sign” enables use of the key for Diffie-Hellman key exchange mechanisms (DHE and ECDHE) in TLS, which are preferred because they offer forward secrecy. Selecting “encrypt” enables RSA key exchange mechanisms, which are still common in some places. Selecting both enables both key exchange mechanisms.

Now for some real data:

  Enter the X.509 subject name: CN=example.com

This is the most important value for a server certificate. Enter here the canonical name of your server machine. You may add other virtual server names later.

  E-Mail addresses (end with an empty line):
  > 

We don’t need email addresses in a TLS server certificate and CAcert would anyway ignore such a request. Thus just hit enter.

If you want to create a client certificate for email encryption, this would be the place to enter your mail address (e.g. joe@example.org). You may enter as many addresses as you like, however the CA may not accept them all or reject the entire request.

  Enter DNS names (optional; end with an empty line):
  > example.com
  > www.example.com
  > 

Here I entered the names of the services which the machine actually provides. You almost always want to include the canonical name here too. The browser will accept a certificate for any of these names. As usual the CA must approve all of these names.

  URIs (optional; end with an empty line):
  >

It is possible to insert arbitrary URIs into a certificate; for a server certificate this does not make sense.

  Create self-signed certificate? (y/N)

Since we are creating a certificate signing request, and not a full certificate, we answer no here, or just hit enter for the default.

We have now entered all required information and gpgsm will display what it has gathered and ask whether to create the certificate request:

  These parameters are used:
      Key-Type: RSA
      Key-Length: 3072
      Key-Usage: sign, encrypt
      Name-DN: CN=example.com
      Name-DNS: example.com
      Name-DNS: www.example.com

  Proceed with creation? (y/N) y

gpgsm will now start working on creating the request. As this includes the creation of an RSA key it may take a while. During this time you will be asked 3 times for a passphrase to protect the created private key on your system. A pop up window will appear to ask for it. The first two prompts are for the new passphrase and for re-entering it; the third one is required to actually create the certificate signing request.

When it is ready, you should see the final notice:

  Ready.  You should now send this request to your CA.

Now, you may look at the created request:

  $ cat example.com.cert-req.pem
  -----BEGIN CERTIFICATE REQUEST-----
  MIIClTCCAX0CAQAwFjEUMBIGA1UEAxMLZXhhbXBsZS5jb20wggEiMA0GCSqGSIb3
  DQEBAQUAA4IBDwAwggEKAoIBAQDP1QEcbTvOLLCX4gAoOzH9AW7jNOMj7OSOL0uW
  h2bCdkK5YVpnX212Z6COTC3ZG0pJiCeGt1TbbDJUlTa4syQ6JXavjK66N8ASZsyC
  Rwcl0m6hbXp541t1dbgt2VgeGk25okWw3j+brw6zxLD2TnthJxOatID0lDIG47HW
  GqzZmA6WHbIBIONmGnReIHTpPAPCDm92vUkpKG1xLPszuRmsQbwEl870W/FHrsvm
  DPvVUUSdIvTV9NuRt7/WY6G4nPp9QlIuTf1ESPzIuIE91gKPdrRCAx0yuT708S1n
  xCv3ETQ/bKPoAQ67eE3mPBqkcVwv9SE/2/36Lz06kAizRgs5AgMBAAGgOjA4Bgkq
  hkiG9w0BCQ4xKzApMCcGA1UdEQQgMB6CC2V4YW1wbGUuY29tgg93d3cuZXhhbXBs
  ZS5jb20wDQYJKoZIhvcNAQELBQADggEBAEWD0Qqz4OENLYp6yyO/KqF0ig9FDsLN
  b5/R+qhms5qlhdB5+Dh+j693Sj0UgbcNKc6JT86IuBqEBZmRCJuXRoKoo5aMS1cJ
  hXga7N9IA3qb4VBUzBWvlL92U2Iptr/cEbikFlYZF2Zv3PBv8RfopVlI3OLbKV9D
  bJJTt/6kuoydXKo/Vx4G0DFzIKNdFdJk86o/Ziz8NOs9JjZxw9H9VY5sHKFM5LKk
  VcLwnnLRlNjBGB+9VK/Tze575eG0cJomTp7UGIB+1xzIQVAhUZOizRDv9tHDeaK3
  k+tUhV0kuJcYHucpJycDSrP/uAY5zuVJ0rs2QSjdnav62YrRgEsxJrU=
  -----END CERTIFICATE REQUEST-----
  $

You may now proceed by logging into your account at the CAcert website, choose Server Certificates - New, check sign by class 3 root certificate, paste the above request block into the text field and click on Submit.

If everything works out fine, a certificate will be shown. Now run

$ gpgsm --import

and paste the certificate from the CAcert page into your terminal followed by a Ctrl-D

  -----BEGIN CERTIFICATE-----
  MIIEIjCCAgqgAwIBAgIBTDANBgkqhkiG9w0BAQQFADBUMRQwEgYDVQQKEwtDQWNl
   [...]
  rUTFlNElRXCwIl0YcJkIaYYqWf7+A/aqYJCi8+51usZwMy3Jsq3hJ6MA3h1BgwZs
  Rtct3tIX
  -----END CERTIFICATE-----
  gpgsm: issuer certificate (#/CN=CAcert Class 3 Ro[...]) not found
  gpgsm: certificate imported
  
  gpgsm: total number processed: 1
  gpgsm:               imported: 1

gpgsm tells you that it has imported the certificate. It is now associated with the key you used when creating the request. The root certificate has not been found, so you may want to import it from the CACert website.

To see the content of your certificate, you may now enter:

  $ gpgsm -K example.com
  /home/foo/.gnupg/pubring.kbx
  ---------------------------
  Serial number: 4C
         Issuer: /CN=CAcert Class 3 Root/OU=http:\x2f\x2fwww.[...]
        Subject: /CN=example.com
            aka: (dns-name example.com)
            aka: (dns-name www.example.com)
       validity: 2015-07-01 16:20:51 through 2016-07-01 16:20:51
       key type: 3072 bit RSA
      key usage: digitalSignature keyEncipherment
  ext key usage: clientAuth (suggested), serverAuth (suggested), [...]
    fingerprint: 0F:9C:27:B2:DA:05:5F:CB:33:D8:19:E9:65:B9:4F:BD:B1:98:CC:57

I used -K above because this will only list certificates for which a private key is available. To see more details, you may use --dump-secret-keys instead of -K.

To make actual use of the certificate you need to install it on your server. Server software usually expects a PKCS\#12 file with key and certificate. To create such a file, run:

  $ gpgsm --export-secret-key-p12 -a >example.com-cert.pem

You will be asked for the passphrase as well as for a new passphrase to be used to protect the PKCS\#12 file. The file now contains the certificate as well as the private key:

  $ cat example-cert.pem
  Issuer ...: /CN=CAcert Class 3 Root/OU=http:\x2f\x2fwww.CA[...]
  Serial ...: 4C
  Subject ..: /CN=example.com
      aka ..: (dns-name example.com)
      aka ..: (dns-name www.example.com)
  
  -----BEGIN PKCS12-----
  MIIHlwIBAzCCB5AGCSqGSIb37QdHAaCCB4EEggd9MIIHeTk1BJ8GCSqGSIb3DQEu
  [...many more lines...]
  -----END PKCS12-----
  $

Copy this file in a secure way to the server, install it there and delete the file then. You may export the file again at any time as long as it is available in GnuPG’s private key database.


13 Notes pertaining to certain OSes

GnuPG has been developed on GNU/Linux systems and is know to work on almost all Free OSes. All modern POSIX systems should be supported right now, however there are probably a lot of smaller glitches we need to fix first. The major problem areas are:


13.1 Microsoft Windows Notes

Current limitations are:

  • gpgconf does not create backup files, so in case of trouble your configuration file might get lost.
  • watchgnupg is not available. Logging to sockets is not possible.
  • The periodical smartcard status checking done by scdaemon is not yet supported.

14 How to solve problems

Everyone knows that software often does not do what it should do and thus there is a need to track down problems. We call this debugging in a reminiscent to the moth jamming a relay in a Mark II box back in 1947.

Most of the problems a merely configuration and user problems but nevertheless they are the most annoying ones and responsible for many gray hairs. We try to give some guidelines here on how to identify and solve the problem at hand.


14.1 Debugging Tools

The GnuPG distribution comes with a couple of tools, useful to help find and solving problems.


14.1.1 Scrutinizing a keybox file

A keybox is a file format used to store public keys along with meta information and indices. The commonly used one is the file pubring.kbx in the .gnupg directory. It contains all X.509 certificates as well as OpenPGP keys.

When called the standard way, e.g.:

kbxutil ~/.gnupg/pubring.kbx

it lists all records (called blobs) with there meta-information in a human readable format.

To see statistics on the keybox in question, run it using

kbxutil --stats ~/.gnupg/pubring.kbx

and you get an output like:

Total number of blobs:       99
               header:        1
                empty:        0
              openpgp:        0
                 x509:       98
          non flagged:       81
       secret flagged:        0
    ephemeral flagged:       17

In this example you see that the keybox does not have any OpenPGP keys but contains 98 X.509 certificates and a total of 17 keys or certificates are flagged as ephemeral, meaning that they are only temporary stored (cached) in the keybox and won’t get listed using the usual commands provided by gpgsm or gpg. 81 certificates are stored in a standard way and directly available from gpgsm.

To find duplicated certificates and keyblocks in a keybox file (this should not occur but sometimes things go wrong), run it using

kbxutil --find-dups ~/.gnupg/pubring.kbx


14.2 Various hints on debugging

  • How to find the IP address of a keyserver

    If a round robin URL of is used for a keyserver (e.g. subkeys.gnupg.org); it is not easy to see what server is actually used. Using the keyserver debug option as in

     gpg --keyserver-options debug=1 -v --refresh-key 1E42B367
    

    is thus often helpful. Note that the actual output depends on the backend and may change from release to release.

  • Logging on WindowsCE

    For development, the best logging method on WindowsCE is the use of remote debugging using a log file name of tcp://<ip-addr>:<port>. The command watchgnupg may be used on the remote host to listen on the given port (see option watchgnupg --tcp). For in the field tests it is better to make use of the logging facility provided by the gpgcedev driver (part of libassuan); this is enabled by using a log file name of GPG2: (see option --log-file).


14.3 Commonly Seen Problems

  • Error code ‘Not supported’ from Dirmngr

    Most likely the option enable-ocsp is active for gpgsm but Dirmngr’s OCSP feature has not been enabled using allow-ocsp in dirmngr.conf.

  • The Curses based Pinentry does not work

    The far most common reason for this is that the environment variable GPG_TTY has not been set correctly. Make sure that it has been set to a real tty device and not just to ‘/dev/tty’; i.e. ‘GPG_TTY=tty’ is plainly wrong; what you want is ‘GPG_TTY=`tty`’ — note the back ticks. Also make sure that this environment variable gets exported, that is you should follow up the setting with an ‘export GPG_TTY’ (assuming a Bourne style shell). Even for GUI based Pinentries; you should have set GPG_TTY. See the section on installing the gpg-agent on how to do it.

  • SSH hangs while a popping up pinentry was expected

    SSH has no way to tell the gpg-agent what terminal or X display it is running on. So when remotely logging into a box where a gpg-agent with SSH support is running, the pinentry will get popped up on whatever display the gpg-agent has been started. To solve this problem you may issue the command

    echo UPDATESTARTUPTTY | gpg-connect-agent
    

    and the next pinentry will pop up on your display or screen. However, you need to kill the running pinentry first because only one pinentry may be running at once. If you plan to use ssh on a new display you should issue the above command before invoking ssh or any other service making use of ssh.

  • Exporting a secret key without a certificate

    It may happen that you have created a certificate request using gpgsm but not yet received and imported the certificate from the CA. However, you want to export the secret key to another machine right now to import the certificate over there then. You can do this with a little trick but it requires that you know the approximate time you created the signing request. By running the command

      ls -ltr ~/.gnupg/private-keys-v1.d
    

    you get a listing of all private keys under control of gpg-agent. Pick the key which best matches the creation time and run the command

      /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/libexec/gpg-protect-tool --p12-export \
         ~/.gnupg/private-keys-v1.d/foo >foo.p12
    

    (Please adjust the path to gpg-protect-tool to the appropriate location). foo is the name of the key file you picked (it should have the suffix .key). A Pinentry box will pop up and ask you for the current passphrase of the key and a new passphrase to protect it in the pkcs#12 file.

    To import the created file on the machine you use this command:

      /nix/store/ypbd12dyv4f696pyqvp99gj0hhlb96sf-gnupg-2.3.4/libexec/gpg-protect-tool --p12-import --store  foo.p12
    

    You will be asked for the pkcs#12 passphrase and a new passphrase to protect the imported private key at its new location.

    Note that there is no easy way to match existing certificates with stored private keys because some private keys are used for Secure Shell or other purposes and don’t have a corresponding certificate.

  • A root certificate does not verify

    A common problem is that the root certificate misses the required basicConstraints attribute and thus gpgsm rejects this certificate. An error message indicating “no value” is a sign for such a certificate. You may use the relax flag in trustlist.txt to accept the certificate anyway. Note that the fingerprint and this flag may only be added manually to trustlist.txt.

  • Error message: “digest algorithm N has not been enabled”

    The signature is broken. You may try the option --extra-digest-algo SHA256 to workaround the problem. The number N is the internal algorithm identifier; for example 8 refers to SHA-256.

  • The Windows version does not work under Wine

    When running the W32 version of gpg under Wine you may get an error messages like:

    gpg: fatal: WriteConsole failed: Access denied
    

    The solution is to use the command wineconsole.

    Some operations like --generate-key really want to talk to the console directly for increased security (for example to prevent the passphrase from appearing on the screen). So, you should use wineconsole instead of wine, which will launch a windows console that implements those additional features.

  • Why does GPG’s –search-key list weird keys?

    For performance reasons the keyservers do not check the keys the same way gpg does. It may happen that the listing of keys available on the keyservers shows keys with wrong user IDs or with user Ids from other keys. If you try to import this key, the bad keys or bad user ids won’t get imported, though. This is a bit unfortunate but we can’t do anything about it without actually downloading the keys.


14.4 How the whole thing works internally


14.4.1 How the components work together

GnuPG modules

Figure 14.1: GnuPG module overview


14.4.2 Relationship between GnuPG 1.4 and 2.x

Here is a little picture showing how the different GnuPG versions make use of a smartcard:

GnuPG card architecture

Figure 14.2: GnuPG card architecture


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  7. Conveying Non-Source Forms.

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  8. Additional Terms.

    “Additional permissions” are terms that supplement the terms of this License by making exceptions from one or more of its conditions. Additional permissions that are applicable to the entire Program shall be treated as though they were included in this License, to the extent that they are valid under applicable law. If additional permissions apply only to part of the Program, that part may be used separately under those permissions, but the entire Program remains governed by this License without regard to the additional permissions.

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  9. Termination.

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    Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, you do not qualify to receive new licenses for the same material under section 10.

  10. Acceptance Not Required for Having Copies.

    You are not required to accept this License in order to receive or run a copy of the Program. Ancillary propagation of a covered work occurring solely as a consequence of using peer-to-peer transmission to receive a copy likewise does not require acceptance. However, nothing other than this License grants you permission to propagate or modify any covered work. These actions infringe copyright if you do not accept this License. Therefore, by modifying or propagating a covered work, you indicate your acceptance of this License to do so.

  11. Automatic Licensing of Downstream Recipients.

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  12. Patents.

    A “contributor” is a copyright holder who authorizes use under this License of the Program or a work on which the Program is based. The work thus licensed is called the contributor’s “contributor version”.

    A contributor’s “essential patent claims” are all patent claims owned or controlled by the contributor, whether already acquired or hereafter acquired, that would be infringed by some manner, permitted by this License, of making, using, or selling its contributor version, but do not include claims that would be infringed only as a consequence of further modification of the contributor version. For purposes of this definition, “control” includes the right to grant patent sublicenses in a manner consistent with the requirements of this License.

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    Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law.

  13. No Surrender of Others’ Freedom.

    If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.

  14. Use with the GNU Affero General Public License.

    Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.

  15. Revised Versions of this License.

    The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

    Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.

    If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Program.

    Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.

  16. Disclaimer of Warranty.

    THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  17. Limitation of Liability.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

  18. Interpretation of Sections 15 and 16.

    If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

one line to give the program's name and a brief idea of what it does.
Copyright (C) year name of author

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see https://www.gnu.org/licenses/.

Also add information on how to contact you by electronic and paper mail.

If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:

program Copyright (C) year name of author
This program comes with ABSOLUTELY NO WARRANTY; for details
type ‘show w’.  This is free software, and you are
welcome to redistribute it under certain conditions;
type ‘show c’ for details.

The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, your program’s commands might be different; for a GUI interface, you would use an “about box”.

You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see https://www.gnu.org/licenses/.

The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read https://www.gnu.org/philosophy/why-not-lgpl.html.


Contributors to GnuPG

The GnuPG project would like to thank its many contributors. Without them the project would not have been nearly as successful as it has been. Any omissions in this list are accidental. Feel free to contact the maintainer if you have been left out or some of your contributions are not listed.

David Shaw, Matthew Skala, Michael Roth, Niklas Hernaeus, Nils Ellmenreich, Rémi Guyomarch, Stefan Bellon, Timo Schulz and Werner Koch wrote the code. Birger Langkjer, Daniel Resare, Dokianakis Theofanis, Edmund GRIMLEY EVANS, Gaël Quéri, Gregory Steuck, Nagy Ferenc László, Ivo Timmermans, Jacobo Tarri’o Barreiro, Janusz Aleksander Urbanowicz, Jedi Lin, Jouni Hiltunen, Laurentiu Buzdugan, Magda Procha’zkova’, Michael Anckaert, Michal Majer, Marco d’Itri, Nilgun Belma Buguner, Pedro Morais, Tedi Heriyanto, Thiago Jung Bauermann, Rafael Caetano dos Santos, Toomas Soome, Urko Lusa, Walter Koch, Yosiaki IIDA did the official translations. Mike Ashley wrote and maintains the GNU Privacy Handbook. David Scribner is the current FAQ editor. Lorenzo Cappelletti maintains the web site.

The new modularized architecture of gnupg 1.9 as well as the X.509/CMS part has been developed as part of the Ägypten project. Direct contributors to this project are: Bernhard Herzog, who did extensive testing and tracked down a lot of bugs. Bernhard Reiter, who made sure that we met the specifications and the deadlines. He did extensive testing and came up with a lot of suggestions. Jan-Oliver Wagner made sure that we met the specifications and the deadlines. He also did extensive testing and came up with a lot of suggestions. Karl-Heinz Zimmer and Marc Mutz had to struggle with all the bugs and misconceptions while working on KDE integration. Marcus Brinkman extended GPGME, cleaned up the Assuan code and fixed bugs all over the place. Moritz Schulte took over Libgcrypt maintenance and developed it into a stable an useful library. Steffen Hansen had a hard time to write the dirmngr due to underspecified interfaces. Thomas Koester did extensive testing and tracked down a lot of bugs. Werner Koch designed the system and wrote most of the code.

The following people helped greatly by suggesting improvements, testing, fixing bugs, providing resources and doing other important tasks: Adam Mitchell, Albert Chin, Alec Habig, Allan Clark, Anand Kumria, Andreas Haumer, Anthony Mulcahy, Ariel T Glenn, Bob Mathews, Bodo Moeller, Brendan O’Dea, Brenno de Winter, Brian M. Carlson, Brian Moore, Brian Warner, Bryan Fullerton, Caskey L. Dickson, Cees van de Griend, Charles Levert, Chip Salzenberg, Chris Adams, Christian Biere, Christian Kurz, Christian von Roques, Christopher Oliver, Christian Recktenwald, Dan Winship, Daniel Eisenbud, Daniel Koening, Dave Dykstra, David C Niemi, David Champion, David Ellement, David Hallinan, David Hollenberg, David Mathog, David R. Bergstein, Detlef Lannert, Dimitri, Dirk Lattermann, Dirk Meyer, Disastry, Douglas Calvert, Ed Boraas, Edmund GRIMLEY EVANS, Edwin Woudt, Enzo Michelangeli, Ernst Molitor, Fabio Coatti, Felix von Leitner, fish stiqz, Florian Weimer, Francesco Potorti, Frank Donahoe, Frank Heckenbach, Frank Stajano, Frank Tobin, Gabriel Rosenkoetter, Gaël Quéri, Gene Carter, Geoff Keating, Georg Schwarz, Giampaolo Tomassoni, Gilbert Fernandes, Greg Louis, Greg Troxel, Gregory Steuck, Gregery Barton, Harald Denker, Holger Baust, Hendrik Buschkamp, Holger Schurig, Holger Smolinski, Holger Trapp, Hugh Daniel, Huy Le, Ian McKellar, Ivo Timmermans, Jan Krueger, Jan Niehusmann, Janusz A. Urbanowicz, James Troup, Jean-loup Gailly, Jeff Long, Jeffery Von Ronne, Jens Bachem, Jeroen C. van Gelderen, J Horacio MG, J. Michael Ashley, Jim Bauer, Jim Small, Joachim Backes, Joe Rhett, John A. Martin, Johnny Teveßen, Jörg Schilling, Jos Backus, Joseph Walton, Juan F. Codagnone, Jun Kuriyama, Kahil D. Jallad, Karl Fogel, Karsten Thygesen, Katsuhiro Kondou, Kazu Yamamoto, Keith Clayton, Kevin Ryde, Klaus Singvogel, Kurt Garloff, Lars Kellogg-Stedman, L. Sassaman, M Taylor, Marcel Waldvogel, Marco d’Itri, Marco Parrone, Marcus Brinkmann, Mark Adler, Mark Elbrecht, Mark Pettit, Markus Friedl, Martin Kahlert, Martin Hamilton, Martin Schulte, Matt Kraai, Matthew Skala, Matthew Wilcox, Matthias Urlichs, Max Valianskiy, Michael Engels, Michael Fischer v. Mollard, Michael Roth, Michael Sobolev, Michael Tokarev, Nicolas Graner, Mike McEwan, Neal H Walfield, Nelson H. F. Beebe, NIIBE Yutaka, Niklas Hernaeus, Nimrod Zimerman, N J Doye, Oliver Haakert, Oskari Jääskeläinen, Pascal Scheffers, Paul D. Smith, Per Cederqvist, Phil Blundell, Philippe Laliberte, Peter Fales, Peter Gutmann, Peter Marschall, Peter Valchev, Piotr Krukowiecki, QingLong, Ralph Gillen, Rat, Reinhard Wobst, Rémi Guyomarch, Reuben Sumner, Richard Outerbridge, Robert Joop, Roddy Strachan, Roger Sondermann, Roland Rosenfeld, Roman Pavlik, Ross Golder, Ryan Malayter, Sam Roberts, Sami Tolvanen, Sean MacLennan, Sebastian Klemke, Serge Munhoven, SL Baur, Stefan Bellon, Dr.Stefan.Dalibor, Stefan Karrmann, Stefan Keller, Steffen Ullrich, Steffen Zahn, Steven Bakker, Steven Murdoch, Susanne Schultz, Ted Cabeen, Thiago Jung Bauermann, Thijmen Klok, Thomas Roessler, Tim Mooney, Timo Schulz, Todd Vierling, TOGAWA Satoshi, Tom Spindler, Tom Zerucha, Tomas Fasth, Tommi Komulainen, Thomas Klausner, Tomasz Kozlowski, Thomas Mikkelsen, Ulf Möller, Urko Lusa, Vincent P. Broman, Volker Quetschke, W Lewis, Walter Hofmann, Walter Koch, Wayne Chapeskie, Wim Vandeputte, Winona Brown, Yosiaki IIDA, Yoshihiro Kajiki and Gerlinde Klaes.

This software has been made possible by the previous work of Chris Wedgwood, Jean-loup Gailly, Jon Callas, Mark Adler, Martin Hellman, Paul Kendall, Philip R. Zimmermann, Peter Gutmann, Philip A. Nelson, Taher Elgamal, Torbjorn Granlund, Whitfield Diffie, some unknown NSA mathematicians and all the folks who have worked hard to create complete and free operating systems.

And finally we’d like to thank everyone who uses these tools, submits bug reports and generally reminds us why we’re doing this work in the first place.


Glossary

ARL

The Authority Revocation List is technical identical to a CRL but used for CAs and not for end user certificates.

Chain model

Verification model for X.509 which uses the creation date of a signature as the date the validation starts and in turn checks that each certificate has been issued within the time frame, the issuing certificate was valid. This allows the verification of signatures after the CA’s certificate expired. The validation test also required an online check of the certificate status. The chain model is required by the German signature law. See also Shell model.

CMS

The Cryptographic Message Standard describes a message format for encryption and digital signing. It is closely related to the X.509 certificate format. CMS was formerly known under the name PKCS#7 and is described by RFC3369.

CRL

The Certificate Revocation List is a list containing certificates revoked by the issuer.

CSR

The Certificate Signing Request is a message send to a CA to ask them to issue a new certificate. The data format of such a signing request is called PCKS#10.

OpenPGP

A data format used to build a PKI and to exchange encrypted or signed messages. In contrast to X.509, OpenPGP also includes the message format but does not explicitly demand a specific PKI. However any kind of PKI may be build upon the OpenPGP protocol.

Keygrip

This term is used by GnuPG to describe a 20 byte hash value used to identify a certain key without referencing to a concrete protocol. It is used internally to access a private key. Usually it is shown and entered as a 40 character hexadecimal formatted string.

OCSP

The Online Certificate Status Protocol is used as an alternative to a CRL. It is described in RFC 2560.

PSE

The Personal Security Environment describes a database to store private keys. This is either a smartcard or a collection of files on a disk; the latter is often called a Soft-PSE.

Shell model

The standard model for validation of certificates under X.509. At the time of the verification all certificates must be valid and not expired. See also Chain model.

X.509

Description of a PKI used with CMS. It is for example defined by RFC3280.


Option Index

Jump to:   -  
A   B   C   D   E   F   G   H   I   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y  
Index Entry  Section

-
--no-history: gpg-card
--no-history: Invoking gpg-connect-agent
--override-compliance-check: GPG Esoteric Options

A
add-servers: Dirmngr Options
aead-algo: GPG Esoteric Options
agent-program: GPG Configuration Options
agent-program: Configuration Options
agent-program: gpg-card
agent-program: Invoking gpg-connect-agent
allow-admin: Scdaemon Options
allow-emacs-pinentry: Agent Options
allow-freeform-uid: GPG Esoteric Options
allow-loopback-pinentry: Agent Options
allow-non-selfsigned-uid: GPG Esoteric Options
allow-ocsp: Dirmngr Options
allow-old-cipher-algos: GPG Esoteric Options
allow-preset-passphrase: Agent Options
allow-secret-key-import: GPG Esoteric Options
allow-version-check: Dirmngr Options
allow-weak-digest-algos: GPG Esoteric Options
allow-weak-key-signatures: GPG Esoteric Options
always-trust: Deprecated Options
application-priority: Scdaemon Options
armor: GPG Input and Output
armor: Input and Output
ask-cert-expire: GPG Esoteric Options
ask-cert-level: GPG Configuration Options
ask-sig-expire: GPG Esoteric Options
assume-armor: Input and Output
assume-base64: Input and Output
assume-binary: Input and Output
attribute-fd: GPG Esoteric Options
attribute-file: GPG Esoteric Options
authenticate: gpg-card
auto-check-trustdb: GPG Configuration Options
auto-expand-secmem: Agent Options
auto-issuer-key-retrieve: Certificate Options
auto-key-import: GPG Configuration Options
auto-key-locate: GPG Configuration Options
auto-key-retrieve: GPG Configuration Options

B
base64: Input and Output
batch: Agent Options
batch: GPG Configuration Options
bzip2-compress-level: GPG Configuration Options
bzip2-decompress-lowmem: GPG Configuration Options

C
c: Dirmngr Options
cache-cert: dirmngr-client
cafpr: gpg-card
call-dirmngr: Operational GPGSM Commands
call-protect-tool: Operational GPGSM Commands
card-edit: Operational GPG Commands
card-status: Operational GPG Commands
card-timeout: Scdaemon Options
cert-digest-algo: GPG Esoteric Options
cert-notation: GPG Esoteric Options
cert-policy-url: GPG Esoteric Options
change-passphrase: OpenPGP Key Management
change-passphrase: Certificate Management
change-pin: Operational GPG Commands
check: gpg-check-pattern
check-passphrase-pattern: Agent Options
check-signatures: Operational GPG Commands
check-sigs: Operational GPG Commands
check-sym-passphrase-pattern: Agent Options
check-trustdb: Operational GPG Commands
chuid: GPG Esoteric Options
chuid: Esoteric Options
chuid: gpg-card
chuid: Invoking gpgconf
chuid: Invoking gpg-connect-agent
chunk-size: GPG Input and Output
cipher-algo: GPG Esoteric Options
cipher-algo: CMS Options
clear-sign: Operational GPG Commands
clearsign: Operational GPG Commands
cms: gpgtar
command-fd: GPG Esoteric Options
command-file: GPG Esoteric Options
comment: GPG Esoteric Options
compliance: Compliance Options
compliance: Esoteric Options
compliant-needed: GPG Configuration Options
compress-algo: GPG Esoteric Options
compress-level: GPG Configuration Options
connect-quick-timeout: Dirmngr Options
connect-timeout: Dirmngr Options
create: gpgtar
create-socketdir: Invoking gpgconf
csh: Agent Options
csh: Dirmngr Options
ctapi-driver: Scdaemon Options

D
daemon: Agent Commands
daemon: Dirmngr Commands
daemon: Scdaemon Commands
dearmor: Operational GPG Commands
debug: Agent Options
debug: Dirmngr Options
debug: GPG Esoteric Options
debug: Esoteric Options
debug: Scdaemon Options
debug-all: Agent Options
debug-all: Dirmngr Options
debug-all: GPG Esoteric Options
debug-all: Esoteric Options
debug-all: Scdaemon Options
debug-allow-core-dump: Esoteric Options
debug-allow-core-dump: Scdaemon Options
debug-allow-large-chunks: GPG Esoteric Options
debug-assuan-log-cats: Scdaemon Options
debug-disable-ticker: Scdaemon Options
debug-ignore-expiration: Esoteric Options
debug-iolbf: GPG Esoteric Options
debug-iolbf: GPG Esoteric Options
debug-level: Agent Options
debug-level: Dirmngr Options
debug-level: GPG Esoteric Options
debug-level: Esoteric Options
debug-level: Scdaemon Options
debug-log-tid: Scdaemon Options
debug-no-chain-validation: Esoteric Options
debug-pinentry: Agent Options
debug-quick-random: Agent Options
debug-wait: Agent Options
debug-wait: Dirmngr Options
debug-wait: Scdaemon Options
debug-wait: Scdaemon Options
decode: Invoking gpg-connect-agent
decrypt: Operational GPG Commands
decrypt: Operational GPGSM Commands
decrypt: gpgtar
decrypt-files: Operational GPG Commands
default-cache-ttl: Agent Options
default-cache-ttl: Agent Options
default-cert-expire: GPG Esoteric Options
default-cert-level: GPG Configuration Options
default-key: GPG Configuration Options
default-key: Input and Output
default-keyserver-url: GPG Esoteric Options
default-new-key-algo string: GPG Esoteric Options
default-preference-list: GPG Esoteric Options
default-recipient: GPG Configuration Options
default-recipient-self: GPG Configuration Options
default-sig-expire: GPG Esoteric Options
delete-keys: Operational GPG Commands
delete-keys: Certificate Management
delete-secret-and-public-key: Operational GPG Commands
delete-secret-keys: Operational GPG Commands
deny-admin: Scdaemon Options
desig-revoke: OpenPGP Key Management
detach-sign: Operational GPG Commands
digest-algo: GPG Esoteric Options
directory: gpgtar
directory: gpg-wks-client
directory: gpg-wks-server
dirmngr: Invoking gpg-connect-agent
dirmngr-program: GPG Configuration Options
dirmngr-program: Configuration Options
dirmngr-program: Invoking gpg-connect-agent
disable-application: Scdaemon Options
disable-ccid: Scdaemon Options
disable-check-own-socket: Agent Options
disable-check-own-socket: Dirmngr Options
disable-cipher-algo: GPG Esoteric Options
disable-crl-checks: Certificate Options
disable-dsa2: GPG Configuration Options
disable-extended-key-format: Agent Options
disable-http: Dirmngr Options
disable-ipv4: Dirmngr Options
disable-ipv6: Dirmngr Options
disable-large-rsa: GPG Configuration Options
disable-ldap: Dirmngr Options
disable-mdc: OpenPGP Options
disable-ocsp: Certificate Options
disable-pinpad: Scdaemon Options
disable-policy-checks: Certificate Options
disable-pubkey-algo: GPG Esoteric Options
disable-scdaemon: Agent Options
disable-signer-uid: OpenPGP Options
disable-trusted-cert-crl-check: Certificate Options
display: Agent Options
display-charset: GPG Configuration Options
display-charset:iso-8859-1: GPG Configuration Options
display-charset:iso-8859-15: GPG Configuration Options
display-charset:iso-8859-2: GPG Configuration Options
display-charset:koi8-r: GPG Configuration Options
display-charset:utf-8: GPG Configuration Options
dry-run: GPG Esoteric Options
dry-run: gpgtar
dump-cert: Certificate Management
dump-chain: Certificate Management
dump-external-keys: Certificate Management
dump-keys: Certificate Management
dump-options: Agent Commands
dump-options: Dirmngr Commands
dump-options: General GPG Commands
dump-options: General GPGSM Commands
dump-options: Scdaemon Commands
dump-secret-keys: Certificate Management

E
edit-card: Operational GPG Commands
edit-key: OpenPGP Key Management
emit-version: GPG Esoteric Options
enable-crl-checks: Certificate Options
enable-dsa2: GPG Configuration Options
enable-extended-key-format: Agent Options
enable-issuer-based-crl-check: Certificate Options
enable-large-rsa: GPG Configuration Options
enable-ocsp: Certificate Options
enable-passphrase-history: Agent Options
enable-pinpad-varlen: Scdaemon Options
enable-policy-checks: Certificate Options
enable-progress-filter: GPG Esoteric Options
enable-putty-support: Agent Options
enable-special-filenames: GPG Esoteric Options
enable-special-filenames: gpgv
enable-ssh-support: Agent Options
enable-trusted-cert-crl-check: Certificate Options
enarmor: Operational GPG Commands
encrypt: Operational GPG Commands
encrypt: Operational GPGSM Commands
encrypt: gpgtar
encrypt-files: Operational GPG Commands
encrypt-to: GPG Key related Options
enforce-passphrase-constraints: Agent Options
escape-from-lines: GPG Esoteric Options
exec: Invoking gpg-connect-agent
exec-path: GPG Configuration Options
exit-on-status-write-error: GPG Configuration Options
expert: GPG Configuration Options
export: Operational GPG Commands
export: Certificate Management
export-filter: GPG Input and Output
export-options: GPG Input and Output
export-ownertrust: Operational GPG Commands
export-secret-key-p12: Certificate Management
export-secret-key-p8: Certificate Management
export-secret-key-raw: Certificate Management
export-secret-keys: Operational GPG Commands
export-secret-subkeys: Operational GPG Commands
export-ssh-key: Operational GPG Commands
extra-digest-algo: Esoteric Options
extra-socket: Agent Options
extract: gpgtar

F
factory-reset: gpg-card
faked-system-time: Agent Options
faked-system-time: GPG Esoteric Options
faked-system-time: Esoteric Options
fast-list-mode: GPG Esoteric Options
fetch: gpg-card
fetch-crl: Dirmngr Commands
fetch-keys: Operational GPG Commands
fingerprint: Operational GPG Commands
fixed-list-mode: GPG Input and Output
flush: Dirmngr Commands
for-your-eyes-only: GPG Esoteric Options
forbid-gen-key: GPG Esoteric Options
force: Dirmngr Options
force: watchgnupg
force-aead: OpenPGP Options
force-crl-refresh: Certificate Options
force-default-responder: dirmngr-client
force-mdc: OpenPGP Options
force-sign-key: GPG Esoteric Options
forcesig: gpg-card
forget: Invoking gpg-preset-passphrase
from: gpg-wks-server
full-gen-key: OpenPGP Key Management
full-generate-key: OpenPGP Key Management
full-timestrings: GPG Esoteric Options

G
gen-key: OpenPGP Key Management
gen-key: Certificate Management
gen-prime: Operational GPG Commands
gen-random: Operational GPG Commands
gen-revoke: OpenPGP Key Management
generate: gpg-card
generate-designated-revocation: OpenPGP Key Management
generate-key: OpenPGP Key Management
generate-key: Certificate Management
generate-revocation: OpenPGP Key Management
gnupg: Compliance Options
gpg: gpgtar
gpg-agent-info: GPG Configuration Options
gpg-args: gpgtar
gpg-program: gpg-card
gpgconf-list: GPG Esoteric Options
gpgconf-test: GPG Esoteric Options
gpgsm-program: gpg-card
grab: Agent Options
group: GPG Key related Options

H
header: gpg-wks-server
help: Agent Commands
help: Dirmngr Commands
help: General GPG Commands
help: General GPGSM Commands
help: Scdaemon Commands
help: gpg-card
help: watchgnupg
help: dirmngr-client
help: gpgtar
help: gpg-wks-client
help: gpg-wks-server
hex: Invoking gpg-connect-agent
hidden-encrypt-to: GPG Key related Options
hidden-recipient: GPG Key related Options
hidden-recipient-file: GPG Key related Options
homedir: Agent Options
homedir: GPG Configuration Options
homedir: Configuration Options
homedir: Scdaemon Options
homedir: gpgv
homedir: Invoking gpgconf
homedir: Invoking gpg-connect-agent
honor-http-proxy: Dirmngr Options
http-proxy: Dirmngr Options

I
ignore-cache-for-signing: Agent Options
ignore-cert: Dirmngr Options
ignore-cert-extension: Dirmngr Options
ignore-cert-extension: Certificate Options
ignore-crc-error: GPG Esoteric Options
ignore-http-dp: Dirmngr Options
ignore-ldap-dp: Dirmngr Options
ignore-mdc-error: GPG Esoteric Options
ignore-ocsp-service-url: Dirmngr Options
ignore-time-conflict: GPG Esoteric Options
ignore-time-conflict: gpgv
ignore-valid-from: GPG Esoteric Options
import: Operational GPG Commands
import: Certificate Management
import-filter: GPG Input and Output
import-options: GPG Input and Output
import-ownertrust: Operational GPG Commands
include-certs: CMS Options
include-key-block: OpenPGP Options
input-size-hint: GPG Input and Output
interactive: GPG Esoteric Options

K
kdf-setup: gpg-card
keep-display: Agent Options
keep-tty: Agent Options
key-origin: GPG Input and Output
keyboxd: Invoking gpg-connect-agent
keyboxd-program: Invoking gpg-connect-agent
keydb-clear-some-cert-flags: Certificate Management
keyedit:addcardkey: OpenPGP Key Management
keyedit:addkey: OpenPGP Key Management
keyedit:addphoto: OpenPGP Key Management
keyedit:addrevoker: OpenPGP Key Management
keyedit:adduid: OpenPGP Key Management
keyedit:bkuptocard: OpenPGP Key Management
keyedit:change-usage: OpenPGP Key Management
keyedit:check: OpenPGP Key Management
keyedit:clean: OpenPGP Key Management
keyedit:cross-certify: OpenPGP Key Management
keyedit:delkey: OpenPGP Key Management
keyedit:delsig: OpenPGP Key Management
keyedit:deluid: OpenPGP Key Management
keyedit:disable: OpenPGP Key Management
keyedit:enable: OpenPGP Key Management
keyedit:expire: OpenPGP Key Management
keyedit:key: OpenPGP Key Management
keyedit:keyserver: OpenPGP Key Management
keyedit:keytocard: OpenPGP Key Management
keyedit:keytotpm: OpenPGP Key Management
keyedit:lsign: OpenPGP Key Management
keyedit:minimize: OpenPGP Key Management
keyedit:notation: OpenPGP Key Management
keyedit:nrsign: OpenPGP Key Management
keyedit:passwd: OpenPGP Key Management
keyedit:pref: OpenPGP Key Management
keyedit:primary: OpenPGP Key Management
keyedit:quit: OpenPGP Key Management
keyedit:revkey: OpenPGP Key Management
keyedit:revsig: OpenPGP Key Management
keyedit:revuid: OpenPGP Key Management
keyedit:save: OpenPGP Key Management
keyedit:setpref: OpenPGP Key Management
keyedit:showphoto: OpenPGP Key Management
keyedit:showpref: OpenPGP Key Management
keyedit:sign: OpenPGP Key Management
keyedit:toggle: OpenPGP Key Management
keyedit:trust: OpenPGP Key Management
keyedit:tsign: OpenPGP Key Management
keyedit:uid: OpenPGP Key Management
keyid-format: GPG Configuration Options
keyring: GPG Configuration Options
keyring: gpgv
keyserver: Dirmngr Options
keyserver: GPG Configuration Options
keyserver: Configuration Options
keyserver-options: GPG Configuration Options
kill: Invoking gpgconf
known-notation: GPG Esoteric Options

L
lang: gpg-card
launch: Invoking gpgconf
lc-ctype: Agent Options
lc-messages: Agent Options
ldap-proxy: Dirmngr Options
ldapserver: Dirmngr Options
ldapserver: Configuration Options
ldapserverlist-file: Dirmngr Options
ldaptimeout: Dirmngr Options
learn-card: Certificate Management
legacy-list-mode: GPG Input and Output
limit-card-insert-tries: GPG Configuration Options
list: gpg-card
list-archive: gpgtar
list-chain: Certificate Management
list-config: GPG Esoteric Options
list-crls: Dirmngr Commands
list-gcrypt-config: GPG Esoteric Options
list-keys: Operational GPG Commands
list-keys: Certificate Management
list-keys: Certificate Management
list-only: GPG Esoteric Options
list-options: GPG Configuration Options
list-options:show-keyring: GPG Configuration Options
list-options:show-keyserver-urls: GPG Configuration Options
list-options:show-notations: GPG Configuration Options
list-options:show-only-fpr-mbox: GPG Configuration Options
list-options:show-photos: GPG Configuration Options
list-options:show-policy-urls: GPG Configuration Options
list-options:show-sig-expire: GPG Configuration Options
list-options:show-sig-subpackets: GPG Configuration Options
list-options:show-std-notations: GPG Configuration Options
list-options:show-uid-validity: GPG Configuration Options
list-options:show-unusable-subkeys: GPG Configuration Options
list-options:show-unusable-uids: GPG Configuration Options
list-options:show-usage: GPG Configuration Options
list-options:show-user-notations: GPG Configuration Options
list-options:sort-sigs: GPG Configuration Options
list-packets: Operational GPG Commands
list-secret-keys: Operational GPG Commands
list-secret-keys: Certificate Management
list-signatures: GPG Esoteric Options
list-sigs: GPG Esoteric Options
listen-backlog: Agent Options
listen-backlog: Dirmngr Options
listen-backlog: Scdaemon Options
load-crl: Dirmngr Commands
load-crl: dirmngr-client
local-user: GPG Key related Options
local-user: Input and Output
local-user: gpgtar
locate-external-keys: Operational GPG Commands
locate-keys: Operational GPG Commands
lock-multiple: GPG Configuration Options
lock-never: GPG Configuration Options
lock-once: GPG Configuration Options
log-file: Agent Options
log-file: Dirmngr Options
log-file: GPG Esoteric Options
log-file: Configuration Options
log-file: Scdaemon Options
log-file: gpgv
logger-fd: GPG Esoteric Options
logger-fd: gpgv
login: gpg-card
lookup: dirmngr-client
lsign-key: OpenPGP Key Management

M
mangle-dos-filenames: GPG Configuration Options
marginals-needed: GPG Configuration Options
max-cache-ttl: Agent Options
max-cache-ttl-ssh: Agent Options
max-cert-depth: GPG Configuration Options
max-output: GPG Input and Output
max-passphrase-days: Agent Options
max-replies: Dirmngr Options
min-cert-level: GPG Configuration Options
min-passphrase-len: Agent Options
min-passphrase-nonalpha: Agent Options
min-rsa-length: Compliance Options
min-rsa-length: Esoteric Options
multi-server: Scdaemon Commands
multifile: Operational GPG Commands

N
name: gpg-card
nameserver: Dirmngr Options
no: GPG Configuration Options
no-allow-external-cache: Agent Options
no-allow-loopback-pinentry: Agent Options
no-allow-mark-trusted: Agent Options
no-armor: GPG Input and Output
no-auto-key-import: GPG Configuration Options
no-auto-key-retrieve: GPG Configuration Options
no-auto-trust-new-key: GPG Esoteric Options
no-autostart: GPG Configuration Options
no-autostart: Configuration Options
no-autostart: gpg-card
no-autostart: Invoking gpg-connect-agent
no-batch: GPG Configuration Options
no-common-certs-import: Esoteric Options
no-default-keyring: GPG Esoteric Options
no-default-recipient: GPG Configuration Options
no-detach: Agent Options
no-detach: Scdaemon Options
no-encrypt-to: GPG Key related Options
no-expensive-trust-checks: GPG Esoteric Options
no-ext-connect: Invoking gpg-connect-agent
no-grab: Agent Options
no-greeting: GPG Configuration Options
no-groups: GPG Key related Options
no-include-key-block: OpenPGP Options
no-keyring: GPG Esoteric Options
no-literal: GPG Esoteric Options
no-mangle-dos-filenames: GPG Configuration Options
no-options: GPG Configuration Options
no-random-seed-file: GPG Configuration Options
no-secmem-warning: GPG Configuration Options
no-secmem-warning: Configuration Options
no-sig-cache: GPG Configuration Options
no-skip-hidden-recipients: GPG Key related Options
no-symkey-cache: GPG Esoteric Options
no-tty: GPG Configuration Options
no-use-standard-socket: Agent Options
no-use-tor: Dirmngr Options
no-verbose: GPG Configuration Options
not-dash-escaped: GPG Esoteric Options
null: gpgtar
null: gpg-check-pattern

O
ocsp: dirmngr-client
ocsp-current-period: Dirmngr Options
ocsp-max-clock-skew: Dirmngr Options
ocsp-max-period: Dirmngr Options
ocsp-responder: Dirmngr Options
ocsp-signer: Dirmngr Options
only-ldap-proxy: Dirmngr Options
openpgp: Compliance Options
openpgp: gpgtar
options: Agent Options
options: Dirmngr Options
options: Dirmngr Options
options: GPG Configuration Options
options: Configuration Options
options: Scdaemon Options
output: GPG Input and Output
output: Input and Output
output: gpgv
output: gpgtar
output: gpg-wks-client
output: gpg-wks-server
override-session-key: GPG Esoteric Options

P
p12-charset: Input and Output
passphrase: GPG Esoteric Options
passphrase: Invoking gpg-preset-passphrase
passphrase-fd: GPG Esoteric Options
passphrase-fd: Esoteric Options
passphrase-file: GPG Esoteric Options
passphrase-repeat: GPG Esoteric Options
passwd: OpenPGP Key Management
passwd: Certificate Management
passwd: gpg-card
pcsc-driver: Scdaemon Options
pcsc-shared: Scdaemon Options
pem: dirmngr-client
permission-warning: GPG Configuration Options
personal-aead-preferences: OpenPGP Options
personal-cipher-preferences: OpenPGP Options
personal-compress-preferences: OpenPGP Options
personal-digest-preferences: OpenPGP Options
pgp6: Compliance Options
pgp7: Compliance Options
pgp8: Compliance Options
photo-viewer: GPG Configuration Options
pinentry-formatted-passphrase: Agent Options
pinentry-invisible-char: Agent Options
pinentry-mode: GPG Esoteric Options
pinentry-mode: Esoteric Options
pinentry-program: Agent Options
pinentry-timeout: Agent Options
pinentry-touch-file: Agent Options
ping: dirmngr-client
policy-file: Configuration Options
prefer-system-dirmngr: Configuration Options
preserve-permissions: GPG Esoteric Options
preset: Invoking gpg-preset-passphrase
primary-keyring: GPG Configuration Options
print-md: Operational GPG Commands
privatedo: gpg-card

Q
q: gpg-card
q: Invoking gpg-connect-agent
quick-add-key: OpenPGP Key Management
quick-add-uid: OpenPGP Key Management
quick-gen-key: OpenPGP Key Management
quick-generate-key: OpenPGP Key Management
quick-lsign-key: OpenPGP Key Management
quick-revoke-sig: OpenPGP Key Management
quick-revoke-uid: OpenPGP Key Management
quick-set-expire: OpenPGP Key Management
quick-set-primary-uid: OpenPGP Key Management
quick-sign-key: OpenPGP Key Management
quiet: Agent Options
quiet: GPG Configuration Options
quiet: gpg-card
quiet: gpgv
quiet: Invoking gpgconf
quiet: Invoking gpg-connect-agent
quiet: dirmngr-client
quiet: gpgtar
quiet: gpg-wks-client
quiet: gpg-wks-server
quit: gpg-card

R
raw-socket: Invoking gpg-connect-agent
readcert: gpg-card
reader-port: Scdaemon Options
rebuild-keydb-caches: Operational GPG Commands
receive-keys: Operational GPG Commands
recipient: GPG Key related Options
recipient: Input and Output
recipient: gpgtar
recipient-file: GPG Key related Options
recursive-resolver: Dirmngr Options
recv-keys: Operational GPG Commands
refresh-keys: Operational GPG Commands
reload: Invoking gpgconf
remove-socketdir: Invoking gpgconf
request-origin: GPG Esoteric Options
request-origin: Esoteric Options
require-cross-certification: GPG Configuration Options
require-secmem: GPG Configuration Options
reset: gpg-card
resolver-timeout: Dirmngr Options
rfc2440: Compliance Options
rfc4880: Compliance Options
rfc4880bis: Compliance Options
run: Invoking gpg-connect-agent

S
s: Dirmngr Options
s2k-calibration: Agent Options
s2k-cipher-algo: OpenPGP Options
s2k-count: Agent Options
s2k-count: OpenPGP Options
s2k-digest-algo: OpenPGP Options
s2k-mode: OpenPGP Options
salut: gpg-card
salutation: gpg-card
scdaemon-program: Agent Options
search-keys: Operational GPG Commands
secret-keyring: GPG Configuration Options
send: gpg-wks-client
send: gpg-wks-server
send-keys: Operational GPG Commands
sender: GPG Key related Options
server: Agent Commands
server: Dirmngr Commands
server: Operational GPGSM Commands
server: Scdaemon Commands
set-filename: GPG Esoteric Options
set-filename: gpgtar
set-filesize: GPG Esoteric Options
set-notation: GPG Esoteric Options
set-policy-url: GPG Esoteric Options
sh: Agent Options
sh: Dirmngr Options
show-certs: Certificate Management
show-keyring: Deprecated Options
show-keys: Operational GPG Commands
show-notation: Deprecated Options
show-photos: Deprecated Options
show-policy-url: Deprecated Options
show-session-key: GPG Esoteric Options
shutdown: Dirmngr Commands
sig-keyserver-url: GPG Esoteric Options
sig-notation: GPG Esoteric Options
sig-policy-url: GPG Esoteric Options
sign: Operational GPG Commands
sign: Operational GPGSM Commands
sign-key: OpenPGP Key Management
skip-crypto: gpgtar
skip-hidden-recipients: GPG Key related Options
skip-verify: GPG Esoteric Options
squid-mode: dirmngr-client
ssh-fingerprint-digest: Agent Options
standard-resolver: Dirmngr Options
status-fd: GPG Esoteric Options
status-fd: gpg-card
status-fd: gpgv
status-fd: Invoking gpgconf
status-fd: gpg-wks-client
status-file: GPG Esoteric Options
steal-socket: Agent Options
store: Operational GPG Commands
subst: Invoking gpg-connect-agent
supervised: Agent Commands
supervised: Dirmngr Commands
symmetric: Operational GPG Commands

T
tar: gpgtar
tar-args: gpgtar
textmode: OpenPGP Options
throw-keyids: GPG Esoteric Options
time-only: watchgnupg
tls-debug: Dirmngr Options
tofu-default-policy: GPG Configuration Options
tofu-policy: Operational GPG Commands
trust-model: GPG Configuration Options
trust-model:always: GPG Configuration Options
trust-model:auto: GPG Configuration Options
trust-model:classic: GPG Configuration Options
trust-model:direct: GPG Configuration Options
trust-model:pgp: GPG Configuration Options
trust-model:tofu: GPG Configuration Options
trust-model:tofu+pgp: GPG Configuration Options
trustdb-name: GPG Configuration Options
trusted-key: GPG Configuration Options
try-all-secrets: GPG Key related Options
try-secret-key: GPG Key related Options
ttyname: Agent Options
ttytype: Agent Options

U
uif: gpg-card
unblock: gpg-card
ungroup: GPG Key related Options
unwrap: Operational GPG Commands
update-trustdb: Operational GPG Commands
url: gpg-card
url: dirmngr-client
url: dirmngr-client
use-agent: GPG Configuration Options
use-embedded-filename: GPG Esoteric Options
use-standard-socket: Agent Options
use-standard-socket-p: Agent Options
use-tor: Dirmngr Options
utf8-strings: GPG Configuration Options
utf8-strings: gpgtar

V
v: Dirmngr Options
v: Configuration Options
v: Scdaemon Options
v: dirmngr-client
validate: dirmngr-client
validation-model: Certificate Options
verbose: Agent Options
verbose: Dirmngr Options
verbose: GPG Configuration Options
verbose: Configuration Options
verbose: Scdaemon Options
verbose: gpg-card
verbose: watchgnupg
verbose: gpgv
verbose: Invoking gpg-preset-passphrase
verbose: Invoking gpg-connect-agent
verbose: dirmngr-client
verbose: gpgtar
verbose: gpg-check-pattern
verbose: gpg-wks-client
verbose: gpg-wks-server
verify: Operational GPG Commands
verify: Operational GPGSM Commands
verify: gpg-card
verify-files: Operational GPG Commands
verify-options: GPG Configuration Options
verify-options:show-keyserver-urls: GPG Configuration Options
verify-options:show-notations: GPG Configuration Options
verify-options:show-photos: GPG Configuration Options
verify-options:show-policy-urls: GPG Configuration Options
verify-options:show-primary-uid-only: GPG Configuration Options
verify-options:show-std-notations: GPG Configuration Options
verify-options:show-uid-validity: GPG Configuration Options
verify-options:show-unusable-uids: GPG Configuration Options
verify-options:show-user-notations: GPG Configuration Options
version: Agent Commands
version: Dirmngr Commands
version: General GPG Commands
version: General GPGSM Commands
version: Scdaemon Commands
version: gpg-card
version: watchgnupg
version: dirmngr-client
version: gpgtar
version: gpg-wks-client
version: gpg-wks-server

W
warranty: General GPG Commands
warranty: General GPGSM Commands
weak-digest: GPG Esoteric Options
weak-digest: gpgv
with-colons: GPG Input and Output
with-colons: gpg-card
with-colons: gpg-wks-client
with-dir: gpg-wks-server
with-ephemeral-keys: Esoteric Options
with-file: gpg-wks-server
with-fingerprint: GPG Input and Output
with-icao-spelling: GPG Input and Output
with-key-data: GPG Esoteric Options
with-key-data: Input and Output
with-key-origin: GPG Input and Output
with-keygrip: GPG Input and Output
with-secret: GPG Input and Output
with-secret: Input and Output
with-subkey-fingerprint: GPG Input and Output
with-validation: Input and Output
with-wkd-hash: GPG Input and Output
writecert: gpg-card
writekey: gpg-card

X
xauthority: Agent Options

Y
yes: GPG Configuration Options
yubikey: gpg-card

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Environment Variable and File Index

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Index Entry  Section

.
.gpg-v21-migrated: GPG Configuration

~
~/.gnupg: GPG Configuration

A
ASSUAN_DEBUG: Scdaemon Options

C
COLUMNS: GPG Configuration
com-certs.pem: GPGSM Configuration
common.conf: GPG Configuration
common.conf: GPGSM Configuration

D
dirmngr.conf: Dirmngr Configuration
DISPLAY: GPGSM OPTION

G
GNUPGHOME: Agent Options
GNUPGHOME: GPG Configuration Options
GNUPGHOME: GPG Configuration
GNUPGHOME: Configuration Options
GNUPGHOME: Scdaemon Options
GNUPGHOME: gpgv
GNUPGHOME: Invoking gpgconf
GNUPGHOME: Invoking gpg-connect-agent
GNUPG_BUILD_ROOT: GPG Configuration
gpg-agent.conf: Agent Configuration
gpg.conf: GPG Configuration
gpgconf.ctl: Agent Options
gpgconf.ctl: GPG Configuration Options
gpgconf.ctl: Configuration Options
gpgconf.ctl: Scdaemon Options
gpgconf.ctl: gpgv
gpgconf.ctl: Invoking gpgconf
gpgconf.ctl: Invoking gpg-connect-agent
gpgsm.conf: GPGSM Configuration
GPG_TTY: Invoking GPG-AGENT
GPG_TTY: GPGSM OPTION

H
help.txt: GPGSM Configuration
HKCU\Software\GNU\GnuPG:DefaultLogFile: Agent Options
HKCU\Software\GNU\GnuPG:HomeDir: Agent Options
HKCU\Software\GNU\GnuPG:HomeDir: GPG Configuration Options
HKCU\Software\GNU\GnuPG:HomeDir: Configuration Options
HKCU\Software\GNU\GnuPG:HomeDir: Scdaemon Options
HKCU\Software\GNU\GnuPG:HomeDir: gpgv
HKCU\Software\GNU\GnuPG:HomeDir: Invoking gpgconf
HKCU\Software\GNU\GnuPG:HomeDir: Invoking gpg-connect-agent
HOME: GPG Configuration
http_proxy: Dirmngr Options

L
LANGUAGE: GPG Configuration
LC_CTYPE: GPGSM OPTION
LC_MESSAGES: GPGSM OPTION
LINES: GPG Configuration

O
openpgp-revocs.d: GPG Configuration

P
PATH: GPG Configuration Options
PINENTRY_USER_DATA: GPG Configuration
PINENTRY_USER_DATA: GPGSM OPTION
policies.txt: GPGSM Configuration
private-keys-v1.d: Agent Configuration
pubring.gpg: GPG Configuration
pubring.kbx: GPG Configuration
pubring.kbx: GPGSM Configuration

Q
qualified.txt: GPGSM Configuration

R
random_seed: GPG Configuration
random_seed: GPGSM Configuration

S
S.gpg-agent: GPGSM Configuration
secring.gpg: GPG Configuration
SHELL: Agent Options
sshcontrol: Agent Configuration

T
TERM: GPGSM OPTION
trustdb.gpg: GPG Configuration
trustlist.txt: Agent Configuration

X
XAUTHORITY: GPGSM OPTION

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Index

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Footnotes

(1)

The gpgconf tool might be helpful for frontends as it enables editing this configuration file using percent-escaped strings.

(2)

Using a little social engineering anyone who is able to decrypt the message can check whether one of the other recipients is the one he suspects.

(3)

Please note that currently no locking is done, so concurrent access should be avoided. There are some precautions to avoid corruption with concurrent usage, but results may be inconsistent and some changes may get lost. The stateless design makes it difficult to provide more guarantees.