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.

3.6.1 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.

4.1.1 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: To check whether a file was signed by a certain key the option --assert-signer can be used. As an alternative the gpgv tool can be used. 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 . Please note that the command "openpgp" can be used to switch to the OpenPGP application of cards which by default are presenting another application (e.g. PIV).

--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|16|30 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. The special level 16 uses a quality level of 1 and outputs an endless stream of hex-encoded octets. The special level 30 outputs random as 30 zBase-32 characters.

--gen-prime mode bits ¶

Use the source, Luke :-). The output format is subject to change with any 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. The --dearmor command can also be used to dearmor PEM armors.

--unwrap ¶

This option modifies the command --decrypt to output the original message with the encryption layer removed. Thus the output will be an OpenPGP data structure which often means a signed OpenPGP message. Note that this option 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 one 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.

--quick-add-adsk fpr adskfpr ¶

Directly add an Additional Decryption Subkey to the key identified by the fingerprint fpr. adskfpr is the fingerprint of another key’s encryption subkey. A subkey is commonly used here because by default a primary key has no encryption capability. Use the option --with-subkey-fingerprint with a list command to display the subkey fingerprints.

--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 useful in distinct communities or groups to implement the concept of a Trusted Introducer. 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. Note that an unattended version of this command is available as --quick-update-pref.

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).

addadsk

Add an Additional Decryption Subkey. The user is asked to enter the fingerprint of another encryption subkey. Note that the exact fingerprint of another key’s encryption subkey needs to be entered. This is because commonly the primary key has no encryption capability. Use the option --with-subkey-fingerprint with a list command to display the subkey fingerprints.

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.

--quick-update-pref user-id ¶

This command updates the preference list of the key to the current default value (either built-in or set via --default-preference-list). This is the unattended version of of using "setpref" in the --key-edit menu without giving a list. Note that you can show the preferences in a key listing by using --list-options show-pref or --list-options show-pref-verbose. You should also re-distribute updated keys to your peers.

--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.

4.2.1 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. It is suggested to use a fingerprint or at least a long keyID for name. 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 and it is suggested to use a fingerprint for name.

--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-filter {select=expr} ¶

A list filter can be used to output only certain keys during key listing commands. For the available property names, see the description of --import-filter.

--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-unusable-sigs

Show key signature made using weak or unsupported algorithms.

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.

--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

--no-compress

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.

Option -z sets both. A value of 0 for n disables compression. A value of -1 forces compression using the default level. Option --no-compress is identical to -z0.

Except for the --store command compression is always used unless gpg detects that the input is already compressed. To inhibit the use of compression use -z0 or --no-compress; to force compression use -z-1 or option z with another compression level than the default as indicated by -1. Note that this overriding of the default deection works only with z and not with the long variant of this option.

--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. The value "none" is explicitly allowed to distinguish between the use of any trusted-key option and no use of this option at all (e.g. due to the --no-options option).

--add-desig-revoker [sensitive:]fingerprint ¶

Add the key specified by fingerprint as a designated revoker to newly created keys. If the fingerprint is prefixed with the keyword “sensitive:” that info is normally not exported wit the key. This option may be given several time to add more than one designated revoker. If the keyword “clear” is used instead of a fingerprint, all designated options previously encountered are discarded. Designated revokers are marked on the key as non-revocable. Note that a designated revoker specified using a parameter file will also be added to the key.

--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 experimental 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 experimental 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.

--always-trust ¶

Identical to --trust-model always.

--assert-signer fpr_or_file ¶

This option checks whether at least one valid signature on a file has been made with the specified key. The key is either specified as a fingerprint or a file listing fingerprints. The fingerprint must be given or listed in compact format (no colons or spaces in between). This option can be given multiple times and each fingerprint is checked against the signing key as well as the corresponding primary key. If fpr_or_file specifies a file, empty lines are ignored as well as all lines starting with a hash sign. With this option gpg is guaranteed to return with an exit code of 0 if and only if a signature has been encountered, is valid, and the key matches one of the fingerprints given by this option.

--assert-pubkey-algo algolist ¶

During data signature verification this options checks whether the used public key algorithm matches the algorithms given by algolist. This option can be given multiple times to concatenate more algorithms to the list; the delimiter of the list are either commas or spaces.

The algorithm names given in the list may either be verbatim names like "ed25519" with an optional leading single equal sign, or being prefixed with ">", ">=", "<=", or "<". That prefix operator is applied to the number part of the algorithm name; for example 2048 in "rsa2048" or 384 in "brainpoolP384r1". If the the leading non-digits in the name matches, the prefix operator is used to compare the number part, a trailing suffix is ignored in this case. For example an algorithm list ">rsa3000, >=brainpool384r1, =ed25519" allows RSA signatures with more that 3000 bits, Brainpool curves 384 and 512, and the ed25519 algorithm.

With this option gpg (and also gpgv) is guaranteed to return with an exit code of 0 if and only if all valid signatures on data are made using a matching algorithm from the given list.

--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 one 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 one 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 one 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 explicitly 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/chpkba53g5gfap7xjy7dwf269f162dyh-gnupg-2.4.5/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.

4.2.2 Key related options ¶

--recipient name ¶

-r

Encrypt for user id name. If this option or --hidden-recipient is not specified, GnuPG asks for the user-id unless --default-recipient is given.

--hidden-recipient name ¶

-R

Encrypt for user ID name, but hide the key ID of this user’s key. This option helps to hide the receiver of the message and is a limited countermeasure against traffic analysis. If this option or --recipient is not specified, GnuPG asks for the user ID unless --default-recipient is given.

--recipient-file file ¶

-f

This option is similar to --recipient except that it encrypts to a key stored in the given file. file must be the name of a file containing exactly one key. gpg assumes that the key in this file is fully valid.

--hidden-recipient-file file ¶

-F

This option is similar to --hidden-recipient except that it encrypts to a key stored in the given file. file must be the name of a file containing exactly one key. gpg assumes that the key in this file is fully valid.

--encrypt-to name ¶

Same as --recipient but this one is intended for use in the options file and may be used with your own user-id as an "encrypt-to-self". It is suggested to use a fingerprint or at least a long keyID for name. These keys are only used when there are other recipients given either by use of --recipient or by the asked user id. No trust checking is performed for these user ids and even disabled keys can be used.

--hidden-encrypt-to name ¶

Same as --hidden-recipient but this one is intended for use in the options file and may be used with your own user-id as a hidden "encrypt-to-self". It is suggested to use a fingerprint or at least a long keyID for name. These keys are only used when there are other recipients given either by use of --recipient or by the asked user id. No trust checking is performed for these user ids and even disabled keys can be used.

--no-encrypt-to ¶

Disable the use of all --encrypt-to and --hidden-encrypt-to keys.

--group {name=value} ¶

Sets up a named group, which is similar to aliases in email programs. Any time the group name is a recipient (-r or --recipient), it will be expanded to the values specified. Multiple groups with the same name are automatically merged into a single group.

The values are key IDs or fingerprints, but any key description is accepted. Note that a value with spaces in it will be treated as two different values. Note also there is only one level of expansion — you cannot make an group that points to another group. When used from the command line, it may be necessary to quote the argument to this option to prevent the shell from treating it as multiple arguments.

--ungroup name ¶

Remove a given entry from the --group list.

--no-groups ¶

Remove all entries from the --group list.

--local-user name ¶

-u

Use name as the key to sign with. Note that this option overrides --default-key.

--sender mbox ¶

This option has two purposes. mbox must either be a complete user ID containing a proper mail address or just a plain mail address. The option can be given multiple times.

When creating a signature this option tells gpg the signing key’s user id used to make the signature and embeds that user ID into the created signature (using OpenPGP’s “Signer’s User ID” subpacket). If the option is given multiple times a suitable user ID is picked. However, if the signing key was specified directly by using a mail address (i.e. not by using a fingerprint or key ID) this option is used and the mail address is embedded in the created signature.

When verifying a signature mbox is used to restrict the information printed by the TOFU code to matching user IDs. If the option is used and the signature contains a “Signer’s User ID” subpacket that information is is also used to restrict the printed information. Note that GnuPG considers only the mail address part of a User ID.

If this option or the said subpacket is available the TRUST lines as printed by option status-fd correspond to the corresponding User ID; if no User ID is known the TRUST lines are computed directly on the key and do not give any information about the User ID. In the latter case it his highly recommended to scripts and other frontends to evaluate the VALIDSIG line, retrieve the key and print all User IDs along with their validity (trust) information.

--try-secret-key name ¶

For hidden recipients GPG needs to know the keys to use for trial decryption. The key set with --default-key is always tried first, but this is often not sufficient. This option allows setting more keys to be used for trial decryption. Although any valid user-id specification may be used for name it makes sense to use at least the long keyid to avoid ambiguities. Note that gpg-agent might pop up a pinentry for a lot keys to do the trial decryption. If you want to stop all further trial decryption you may use close-window button instead of the cancel button.

--try-all-secrets ¶

Don’t look at the key ID as stored in the message but try all secret keys in turn to find the right decryption key. This option forces the behaviour as used by anonymous recipients (created by using --throw-keyids or --hidden-recipient) and might come handy in case where an encrypted message contains a bogus key ID.

--skip-hidden-recipients ¶

--no-skip-hidden-recipients

During decryption skip all anonymous recipients. This option helps in the case that people use the hidden recipients feature to hide their own encrypt-to key from others. If one has many secret keys this may lead to a major annoyance because all keys are tried in turn to decrypt something which was not really intended for it. The drawback of this option is that it is currently not possible to decrypt a message which includes real anonymous recipients.

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.

ignore-attributes

Ignore all attribute user IDs (photo IDs) and their signatures while importing a 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.

select

This filter is only implemented by --list-filter. All property names may be used.

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. Note that all property names may also be used by --list-filter.

Property names may be prefix with a scope delimited by a slash. Valid scopes are "pub" for public and secret primary keys, "sub" for public and secret subkeys, "uid" for for user-ID packets, and "sig" for signature packets. Invalid scopes are currently ignored.

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)

algostr

A string with the key algorithm description. For example "rsa3072" or "ed25519".

key_algo

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

key_size

A number with the effective key size 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)

key_expires

key_expires_d

The expiration time of a public key or subkey or 0 if it does not expire. The second is the same but given as an ISO date string or an empty string e.g. "2038-01-19".

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.

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_expires

sig_expires_d

The expiration time of a signature packet or 0 if it does not expire. The second is the same but given as an ISO date string or an empty string e.g. "2038-01-19".

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)

origin

A string with the key origin or a question mark. For example the string “wkd” is used if a key originated from a Web Key Directory lookup.

lastupd

The timestamp the key was last updated from a keyserver or the Web Key Directory.

url

A string with the the URL associated wit the last key lookup.

--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-revocs

Export only standalone revocation certificates of the key. This option does not export revocations of 3rd party certificate revocations.

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.

mode1003

Enable the use of a new secret key export format. This format avoids the re-encryption as required with the current OpenPGP format and also improves the security of the secret key if it has been protected with a passphrase. Note that an unprotected key is exported as-is and thus not secure; the general rule to convey secret keys in an OpenPGP encrypted file still applies with this mode. Versions of GnuPG before 2.4.0 are not able to import such a secret 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-v5-fingerprint ¶

In a colon mode listing emit "fp2" lines for version 4 OpenPGP keys having a v5 style fingerprint of the key.

--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 ¶

--force-ocb ¶

--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. --force-aead is an alias and deprecated. See also option --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-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.

--require-compliance ¶

To check that data has been encrypted according to the rules of the current compliance mode, a gpg user needs to evaluate the status lines. This is allows frontends to handle compliance check in a more flexible way. However, for scripted use the required evaluation of the status-line requires quite some effort; this option can be used instead to make sure that the gpg process exits with a failure if the compliance rules are not fulfilled. Note that this option has currently an effect only in "de-vs" mode.

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.

--compatibility-flags flags ¶

Set compatibility flags to work around problems due to non-compliant keys or data. The flags are given as a comma separated list of flag names and are OR-ed together. The special flag "none" clears the list and allows one to start over with an empty list. To get a list of available flags the sole word "help" can be used.

--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 one to specify a limit of up to 4 EiB (--chunk-size 62).

--debug-ignore-expiration ¶

This option tries to override certain key expiration dates. It is only useful for certain regression tests.

--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.

--log-time ¶

Prefix all log output with a timestamp even if no log file is used.

--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 by giving the sender control on how to store files. Defaults to no. Note that the option --output overrides this option.

A better approach than using this option is to decrypt to a temporary filename and then rename that file to the embedded file name after checking that the embedded filename is harmless. When using the --status-fd option gpg tells the filename as part of the PLAINTEXT status message. If the filename is important, the use of gpgtar is another option because gpgtar will never overwrite a file but decrypt the files to a new directory.

Note also that unless a modern version 5 signature is used the embedded filename is not part of the signed data.

--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.

--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 one to override this restriction.

--override-compliance-check

This was a temporary introduced option and has no more effect.

--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 ¶

-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 was useful when communicating between two platforms with different line ending conventions (UNIX-like to Mac, Mac to Windows, etc). --no-textmode disables this option, and is the default. Note that this is a legacy option which should not anymore be used by any modern software.

--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.

--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.

--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.

--personal-aead-preferences string ¶

This option is deprecated and has no more effect since version 2.3.9.

--aead-algo name

This option is deprecated and has no more effect since version 2.3.9.

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, their 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’ but control statements may be placed anywhere. The order of the parameters does not matter except for ‘Key-Type’. The parameters are only used for the generated keyblock (primary and subkeys); parameters from previous sets are not used. Some syntax checks may be performed. Key commences when either the end of the parameter file is reached, the next ‘Key-Type’ parameter is encountered, or 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 since GnuPG version 2.1.

%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. fpr may not contain spaces or colons. The optional ‘sensitive’ flag marks the designated revoker as sensitive information. Only v4 and v5 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

5.1.1 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.