EasyPG Assistant is an Emacs user interface to GNU Privacy Guard (GnuPG, see Top in Using the GNU Privacy Guard).
EasyPG Assistant is a part of the package called EasyPG, an all-in-one GnuPG interface for Emacs. EasyPG also contains the library interface called EasyPG Library.
This file describes EasyPG Assistant 1.0.0.
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EasyPG Assistant is an Emacs frontend application to GnuPG (GNU Privacy Guard) that provides the following features:
You can use EasyPG Assistant without any Emacs or GnuPG configuration whatsoever, for example to encrypt and decrypt files automatically with symmetric encryption, see Encrypting and Decrypting gpg Files. However, to use the full set of EasyPG Assistant’s functions you should have at least some minimum GnuPG configuration in place.
John Michael Ashley’s GNU Privacy Handbook, available online as part of the GnuPG user guides, provides an introduction to GnuPG use and configuration. In contrast to that, the GnuPG manual (see Top in Using the GNU Privacy Guard) is more of a reference manual.
EasyPG Assistant commands are prefixed by ‘epa-’. For example,
EasyPG Assistant provides several cryptographic features which can be integrated into other Emacs functionalities. For example, automatic encryption/decryption of *.gpg files.
This chapter introduces various commands for typical use cases.
Probably the first step of using EasyPG Assistant is to browse your keyring. M-x epa-list-keys is corresponding to ‘gpg --list-keys’ from the command line.
Show all keys matched with name from the public keyring.
The output looks as follows.
u A5B6B2D4B15813FE Daiki Ueno <ueno@unixuser.org>
A character on the leftmost column indicates the trust level of the key. If it is ‘u’, the key is marked as ultimately trusted. The second column is the key ID, and the rest is the user ID.
You can move over entries by TAB. If you type RET or click button1 on an entry, you will see more detailed information about the key you selected.
u Daiki Ueno <ueno@unixuser.org> u A5B6B2D4B15813FE 1024bits DSA Created: 2001-10-09 Expires: 2007-09-04 Capabilities: sign certify Fingerprint: 8003 7CD0 0F1A 9400 03CA 50AA A5B6 B2D4 B158 13FE u 4447461B2A9BEA2D 2048bits ELGAMAL_E Created: 2001-10-09 Expires: 2007-09-04 Capabilities: encrypt Fingerprint: 9003 D76B 73B7 4A8A E588 10AF 4447 461B 2A9B EA2D
To browse your private keyring, use M-x epa-list-secret-keys.
Show all keys matched with name from the private keyring.
In *Keys* buffer, several commands are available. The common use case is to export some keys to a file. To do that, type m to select keys, type o, and then supply the filename.
Below are other commands related to key management. Some of them take a file as input/output, and others take the current region.
Insert selected keys after the point. It will let you select keys before insertion. By default, it will encode keys in the OpenPGP armor format.
Import keys from file to your keyring.
Import keys from the current region between start and end to your keyring.
Import keys in the OpenPGP armor format in the current region between
start and end. The difference from
epa-import-keys-region
is that
epa-import-armor-in-region
searches armors in the region and
applies epa-import-keys-region
to each of them.
Delete selected keys. If allow-secret is non-nil
, it
also delete the secret keys.
Decrypt the current region between start and end. It replaces the region with the decrypted text.
Decrypt OpenPGP armors in the current region between start and
end. The difference from epa-decrypt-region
is that
epa-decrypt-armor-in-region
searches armors in the region
and applies epa-decrypt-region
to each of them. That is, this
command does not alter the original text around armors.
Verify the current region between start and end. It sends the verification result to the minibuffer or a popup window. It replaces the region with the signed text.
Verify OpenPGP cleartext blocks in the current region between
start and end. The difference from
epa-verify-region
is that epa-verify-cleartext-in-region
searches OpenPGP cleartext blocks in the region and applies
epa-verify-region
to each of them. That is, this command does
not alter the original text around OpenPGP cleartext blocks.
Sign the current region between start and end. By default, it creates a cleartext signature. If a prefix argument is given, it will let you select signing keys, and then a signature type.
Encrypt the current region between start and end. It will let you select recipients. If a prefix argument is given, it will also ask you whether or not to sign the text before encryption and if you answered yes, it will let you select the signing keys.
Decrypt file. If you do not specify the name output to use for the decrypted file, this function prompts for the value to use.
Verify file.
Sign file. If a prefix argument is given, it will let you select signing keys, and then a signature type.
Encrypt file. It will let you select recipients.
EasyPG Assistant extends Dired Mode for GNU Emacs to allow users to easily do cryptographic operations on files. For example,
M-x dired (mark some files) : e (or M-x epa-dired-do-encrypt) (select recipients by 'm' and click [OK])
The following keys are assigned.
Decrypt marked files.
Verify marked files.
Sign marked files.
Encrypt marked files.
EasyPG Assistant provides a minor mode epa-mail-mode
to help
user compose inline OpenPGP messages. Inline OpenPGP is a traditional
style of sending signed/encrypted emails by embedding raw OpenPGP
blobs inside a message body, not using modern MIME format.
NOTE: Inline OpenPGP is not recommended and you should consider to use PGP/MIME. See Inline OpenPGP in E-mail is bad, Mm’kay?.
Once epa-mail-mode
is enabled, the following keys are assigned.
You can do it by C-u 1 M-x epa-mail-mode or through the Customize
interface. Try M-x customize-variable epa-global-mail-mode.
Decrypt OpenPGP armors in the current buffer.
Verify OpenPGP cleartext signed messages in the current buffer.
Compose a signed message from the current buffer, using your default key. With a prefix argument, select the key to use interactively.
Compose an encrypted message from the current buffer.
By default it tries to build the recipient list from ‘to’,
‘cc’, and ‘bcc’ fields of the mail header. To include your
key in the recipient list, use ‘encrypt-to’ option in
~/.gnupg/gpg.conf. This function translates recipient
addresses using the epa-mail-aliases
list. You can also
use that option to ignore specific recipients for encryption purposes.
With prefix argument, asks you to select the recipients interactively, whether to sign, and which key(s) to sign with.
By default, every file whose name ends with .gpg will be treated as encrypted. That is, when you open such a file, the decrypted text is inserted in the buffer rather than encrypted one. Similarly, when you save the buffer to a foo.gpg file, encrypted data is written.
When you save a buffer to an encrypted file for the first time, EasyPG
Assistant presents you a list of keys in a buffer *Keys* where
you can select recipients for encryption. See Key Management, for
a description of the format of that buffer. You can streamline this
recipient selection step by customizing variables
epa-file-encrypt-to
and epa-file-select-keys
described
further below in this section.
If you do not select any recipient during this step, EasyPG Assistant uses symmetric encryption. As a consequence, you have to enter the passphrase twice for every buffer save and every so often for file reads, since the GnuPG Agent caches your passphrase for file reads at least for some time, but not for buffer saves. See Caching Passphrases, for more information.
If you have created your own keypair1, you can select that as recipient, and EasyPG Assistant will use public key encryption for that file. Since GnuPG performs encryption with your public key, it does not prompt for a passphrase for the buffer save, but it will prompt for your passphrase for file reads every now and then, depending on the GnuPG Agent cache configuration.
To encrypt and decrypt files as described above EasyPG Assistant under
certain circumstances uses intermediate temporary files that contain the
plain-text contents of the files it processes. EasyPG Assistant
creates them below the directory returned by function
temporary-file-directory
(see Generating Unique File Names in GNU Emacs Lisp Reference
Manual). If you want to be sure not to leave any plain-text traces,
use an encrypted file systems at least for that directory.
The file name pattern for encrypted files can be controlled by
epa-file-name-regexp
.
Regexp which matches filenames treated as encrypted.
You can disable this behavior with M-x epa-file-disable, and then get it back with M-x epa-file-enable.
Disable automatic encryption/decryption of *.gpg files.
Enable automatic encryption/decryption of *.gpg files.
By default, epa-file
will try to use symmetric encryption, aka
password-based encryption. If you want to use public key encryption
instead, do M-x epa-file-select-keys, which pops up the key
selection dialog.
Select recipient keys to encrypt the currently visiting file with public key encryption.
You can also change the default behavior with the variable
epa-file-select-keys
.
Control whether or not to pop up the key selection dialog.
For frequently visited files, it might be a good idea to tell Emacs
which encryption method should be used through file variables
(see Local Variables in Files in The Emacs
Editor). Use the epa-file-encrypt-to
local variable for this.
For example, if you want an Elisp file to be encrypted with a public key associated with an email address ‘ueno@unixuser.org’, add the following line to the beginning of the file.
;; -*- epa-file-encrypt-to: ("ueno@unixuser.org") -*- |
Instead, if you want the file always (regardless of the value of the
epa-file-select-keys
variable) encrypted with symmetric
encryption, change the line as follows.
;; -*- epa-file-encrypt-to: nil -*- |
Other variables which control the automatic encryption/decryption behavior are below.
If non-nil
, cache passphrase for symmetric encryption. The
default value is nil
.
For security reasons, this option is turned off by default and not recommended to be used. Instead, consider using the GnuPG Agent, which in many cases can do the same job, and does it in a safer way. See Caching Passphrases, for more information.
If non-nil
, disable auto-saving when opening an encrypted file.
The default value is t
.
The epa-search-keys
command can be used to query a
GPG key server. Emacs will then pop up a buffer that lists
the matches, and you can then fetch (and add) keys to your personal
key ring.
In the key search buffer, you can use the f command to mark keys for fetching, and then x to fetch the keys (and incorporate them into your key ring).
The epa-keyserver
variable says which server to query.
As of June 2023, there are three active branches of GnuPG: 2.4, 2.2, and 1.4. GnuPG versions 2.4.1 and later suffer from GnuPG bug T6481 and are hardly usable with Emacs. There is a patch for that bug available at least for GnuPG version 2.4.1, which your operating system or distribution might provide already. GnuPG 1.4 is considered a legacy version.
Besides that, all of those branches mentioned above should work flawlessly with Emacs with basic use-cases. They have, however, some incompatible characteristics, which might be visible when used from Emacs.
gpg-agent
. The GPG_AGENT_INFO
environment variable, which is used by GnuPG 2.0 and 1.4, is ignored.
That means, if your system has both GnuPG 2.1 and 1.4, the gpg command
from GnuPG 1.4 is not able to use gpg-agent
provided by 2.1
(at least out of box).
An important component of the GnuPG suite is the Pinentry, which
allows for secure entry of passphrases requested by GnuPG. GnuPG
delivers various different programs as Pinentry, ranging from bland
TTY-only pinentry-tty
to fancy graphical dialogs for various
desktop environments, like pinentry-gnome3
. Your operating
system usually determines which of these is used by default.
Note that the selection of a concrete Pinentry program determines only how GnuPG queries for passphrases and not how often. For the latter question see Caching Passphrases.
With some configuration Emacs can also play the role of a Pinentry. The most natural choice, available with GnuPG 2.1.5 and later, is to use Emacs itself as Pinentry for requests that are triggered by Emacs. For example, if you open a file whose name ends with .gpg using automatic decryption, you most likely also want to enter the passphrase for that request in Emacs.
This so called loopback Pinentry has the added benefit that it works also when you use Emacs remotely or from a text-only terminal. To enable it:
allow-loopback-pinentry
is configured for
gpg-agent
, which should be the default. See Option Summary in Using the GNU Privacy Guard.
epg-pinentry-mode
to loopback
in
Emacs.
There are other options available to use Emacs as Pinentry, you might
come across a Pinentry called pinentry-emacs
or
gpg-agent
option allow-emacs-pinentry
. However,
these are considered insecure or semi-obsolete and might not be
supported by your operating system or distribution. For example,
Debian GNU/Linux supports only the loopback Pinentry described above.
Typing passphrases is a troublesome task if you frequently open and close the same file. GnuPG and EasyPG Assistant provide mechanisms to remember your passphrases for a limited time. Using these, you only need to re-enter the passphrase occasionally. However, the configuration is a bit confusing since it depends on your GnuPG installation (see GnuPG Version Compatibility), encryption method (symmetric or public key), and whether or not you want to use GnuPG Agent. As an additional constraint, use of the GnuPG Agent is mandatory for GnuPG 2.0 and later. Here are some questions:
Here are configurations depending on your answers:
1 | 2 | 3 | Configuration |
Yes | Yes | Must | Set up GnuPG Agent. |
Yes | No | Must | Set up GnuPG Agent. |
No | Yes | Yes | Set up elisp passphrase cache. |
No | Yes | No | Set up elisp passphrase cache. |
No | No | Yes | Set up GnuPG Agent. |
No | No | No | You can’t, without GnuPG Agent. |
To set up GnuPG Agent, follow the instruction in Invoking GPG-AGENT in Using the GNU Privacy Guard.
To set up elisp passphrase cache, set
epa-file-cache-passphrase-for-symmetric-encryption
.
See Encrypting and Decrypting gpg Files.
Bugs and problems with EasyPG Assistant are actively worked on by the Emacs development team. Feature requests and suggestions are also more than welcome. Use M-x report-emacs-bug, see Reporting Bugs in The Emacs Editor.
When submitting a bug report, please try to describe in excruciating detail the steps required to reproduce the problem. Also try to collect necessary information to fix the bug, such as:
Before reporting the bug, you should set epg-debug
in the
~/.emacs file and repeat the bug. Then, include the contents
of the *epg-debug* buffer. Note that the first letter of the
buffer name is a whitespace.
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with the Invariant Sections being list their titles, with the Front-Cover Texts being list, and with the Back-Cover Texts being list.
If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.
For encryption and
decryption of files you do not intend to share, you do not have to use
an email address as recipient during creation of the keypair. You can
also use some free-form string that gives information on the use of
the keypair, like backup
or account database
.