1GPG-AGENT(1) GNU Privacy Guard GPG-AGENT(1)
2
6 gpg-agent - Secret key management for GnuPG
7
9 gpg-agent [--homedir dir] [--options file] [options]
10 gpg-agent [--homedir dir] [--options file] [options] --server
11 gpg-agent [--homedir dir] [--options file] [options] --daemon [com‐
12 mand_line]
13
16 gpg-agent is a daemon to manage secret (private) keys independently
17 from any protocol. It is used as a backend for gpg and gpgsm as well
18 as for a couple of other utilities.
19 The agent is usualy started on demand by gpg, gpgsm, gpgconf or gpg-
21 connect-agent. Thus there is no reason to start it manually. In case
22 you want to use the included Secure Shell Agent you may start the agent
23 using:
24 gpg-connect-agent /bye
26 The usual way to run the agent is from the ~/.xsession file:
29 eval $(gpg-agent --daemon)
31 If you don't use an X server, you can also put this into your regular
33 startup file ~/.profile or .bash_profile. It is best not to run multi‐
34 ple instance of the gpg-agent, so you should make sure that only one is
35 running: gpg-agent uses an environment variable to inform clients about
36 the communication parameters. You can write the content of this envi‐
37 ronment variable to a file so that you can test for a running agent.
38 Here is an example using Bourne shell syntax:
39 gpg-agent --daemon --enable-ssh-support \
41 --write-env-file "${HOME}/.gpg-agent-info"
42 This code should only be run once per user session to initially fire up
44 the agent. In the example the optional support for the included Secure
45 Shell agent is enabled and the information about the agent is written
46 to a file in the HOME directory. Note that by running gpg-agent with‐
47 out arguments you may test whether an agent is already running; however
48 such a test may lead to a race condition, thus it is not suggested.
49 The second script needs to be run for each interactive session:
52 if [ -f "${HOME}/.gpg-agent-info" ]; then
54 . "${HOME}/.gpg-agent-info"
55 export GPG_AGENT_INFO
56 export SSH_AUTH_SOCK
57 fi
58 It reads the data out of the file and exports the variables. If you
61 don't use Secure Shell, you don't need the last two export statements.
62 You should always add the following lines to your .bashrc or whatever
65 initialization file is used for all shell invocations:
66 GPG_TTY=$(tty)
68 export GPG_TTY
69 It is important that this environment variable always reflects the out‐
72 put of the tty command. For W32 systems this option is not required.
73 Please make sure that a proper pinentry program has been installed
75 under the default filename (which is system dependant) or use the
76 option pinentry-program to specify the full name of that program. It
77 is often useful to install a symbolic link from the actual used pinen‐
78 try (e.g. ‘/usr/bin/pinentry-gtk’) to the expected one (e.g.
79 ‘/usr/bin/pinentry’).
80
85 Commands are not distinguished from options except for the fact that
86 only one command is allowed.
87 --version
90 Print the program version and licensing information. Note that
91 you cannot abbreviate this command.
92 --help
95 -h Print a usage message summarizing the most useful command-line
97 options. Note that you cannot abbreviate this command.
98 --dump-options
101 Print a list of all available options and commands. Note that
102 you cannot abbreviate this command.
103 --server
106 Run in server mode and wait for commands on the stdin. The
107 default mode is to create a socket and listen for commands
108 there.
109 --daemon [command line]
112 Start the gpg-agent as a daemon; that is, detach it from the
113 console and run it in the background. Because gpg-agent prints
114 out important information required for further use, a common way
115 of invoking gpg-agent is: eval $(gpg-agent --daemon) to setup
116 the environment variables. The option --write-env-file is
117 another way commonly used to do this. Yet another way is creat‐
118 ing a new process as a child of gpg-agent: gpg-agent --daemon
119 /bin/sh. This way you get a new shell with the environment set‐
120 up properly; if you exit from this shell, gpg-agent terminates
121 as well.
122
125 --options file
126 Reads configuration from file instead of from the default per-
127 user configuration file. The default configuration file is
128 named ‘gpg-agent.conf’ and expected in the ‘.gnupg’ directory
129 directly below the home directory of the user.
130 --homedir dir
134 Set the name of the home directory to dir. If this option is not
135 used, the home directory defaults to ‘~/.gnupg’. It is only
136 recognized when given on the command line. It also overrides
137 any home directory stated through the environment variable
138 ‘GNUPGHOME’ or (on W32 systems) by means of the Registry entry
139 HKCU\Software\GNU\GnuPG:HomeDir.
140 -v
145 --verbose
147 Outputs additional information while running. You can increase
148 the verbosity by giving several verbose commands to gpgsm, such
149 as '-vv'.
150 -q
153 --quiet
155 Try to be as quiet as possible.
156 --batch
159 Don't invoke a pinentry or do any other thing requiring human
160 interaction.
161 --faked-system-time epoch
164 This option is only useful for testing; it sets the system time
165 back or forth to epoch which is the number of seconds elapsed
166 since the year 1970.
167 --debug-level level
170 Select the debug level for investigating problems. level may be
171 a numeric value or a keyword:
172 none No debugging at all. A value of less than 1 may be used
175 instead of the keyword.
176 basic Some basic debug messages. A value between 1 and 2 may
178 be used instead of the keyword.
179 advanced
181 More verbose debug messages. A value between 3 and 5 may
182 be used instead of the keyword.
183 expert Even more detailed messages. A value between 6 and 8 may
185 be used instead of the keyword.
186 guru All of the debug messages you can get. A value greater
188 than 8 may be used instead of the keyword. The creation
189 of hash tracing files is only enabled if the keyword is
190 used.
191 How these messages are mapped to the actual debugging flags is not
193 specified and may change with newer releases of this program. They are
194 however carefully selected to best aid in debugging.
195 --debug flags
198 This option is only useful for debugging and the behaviour may
199 change at any time without notice. FLAGS are bit encoded and
200 may be given in usual C-Syntax. The currently defined bits are:
201 0 (1) X.509 or OpenPGP protocol related data
204 1 (2) values of big number integers
206 2 (4) low level crypto operations
208 5 (32) memory allocation
210 6 (64) caching
212 7 (128)
214 show memory statistics.
215 9 (512)
217 write hashed data to files named dbgmd-000*
218 10 (1024)
220 trace Assuan protocol
221 12 (4096)
223 bypass all certificate validation
224 --debug-all
227 Same as --debug=0xffffffff
228 --debug-wait n
231 When running in server mode, wait n seconds before entering the
232 actual processing loop and print the pid. This gives time to
233 attach a debugger.
234 --no-detach
237 Don't detach the process from the console. This is mainly use‐
238 ful for debugging.
239 -s
242 --sh
244 -c
246 --csh Format the info output in daemon mode for use with the standard
248 Bourne shell or the C-shell respectively. The default is to
249 guess it based on the environment variable SHELL which is cor‐
250 rect in almost all cases.
251 --write-env-file file
254 Often it is required to connect to the agent from a process not
255 being an inferior of gpg-agent and thus the environment variable
256 with the socket name is not available. To help setting up those
257 variables in other sessions, this option may be used to write
258 the information into file. If file is not specified the default
259 name ‘${HOME}/.gpg-agent-info’ will be used. The format is
260 suitable to be evaluated by a Bourne shell like in this simple
261 example:
262 eval $(cat file)
264 eval $(cut -d= -f 1 < file | xargs echo export)
265 --no-grab
270 Tell the pinentry not to grab the keyboard and mouse. This
271 option should in general not be used to avoid X-sniffing
272 attacks.
273 --log-file file
277 Append all logging output to file. This is very helpful in see‐
278 ing what the agent actually does. If neither a log file nor a
279 log file descriptor has been set on a Windows platform, the Reg‐
280 istry entry HKCU\Software\GNU\GnuPG:DefaultLogFile, if set, is
281 used to specify the logging output.
282 --allow-mark-trusted
287 Allow clients to mark keys as trusted, i.e. put them into the
288 ‘trustlist.txt’ file. This is by default not allowed to make it
289 harder for users to inadvertently accept Root-CA keys.
290 --allow-loopback-pinentry
294 Allow clients to use the loopback pinentry features; see the
295 option pinentry-mode for details.
296 --ignore-cache-for-signing
299 This option will let gpg-agent bypass the passphrase cache for
300 all signing operation. Note that there is also a per-session
301 option to control this behaviour but this command line option
302 takes precedence.
303 --default-cache-ttl n
306 Set the time a cache entry is valid to n seconds. The default
307 is 600 seconds.
308 --default-cache-ttl-ssh n
311 Set the time a cache entry used for SSH keys is valid to n sec‐
312 onds. The default is 1800 seconds.
313 --max-cache-ttl n
316 Set the maximum time a cache entry is valid to n seconds. After
317 this time a cache entry will be expired even if it has been
318 accessed recently. The default is 2 hours (7200 seconds).
319 --max-cache-ttl-ssh n
322 Set the maximum time a cache entry used for SSH keys is valid to
323 n seconds. After this time a cache entry will be expired even
324 if it has been accessed recently. The default is 2 hours (7200
325 seconds).
326 --enforce-passphrase-constraints
329 Enforce the passphrase constraints by not allowing the user to
330 bypass them using the ``Take it anyway'' button.
331 --min-passphrase-len n
334 Set the minimal length of a passphrase. When entering a new
335 passphrase shorter than this value a warning will be displayed.
336 Defaults to 8.
337 --min-passphrase-nonalpha n
340 Set the minimal number of digits or special characters required
341 in a passphrase. When entering a new passphrase with less than
342 this number of digits or special characters a warning will be
343 displayed. Defaults to 1.
344 --check-passphrase-pattern file
347 Check the passphrase against the pattern given in file. When
348 entering a new passphrase matching one of these pattern a warn‐
349 ing will be displayed. file should be an absolute filename. The
350 default is not to use any pattern file.
351 Security note: It is known that checking a passphrase against a
353 list of pattern or even against a complete dictionary is not
354 very effective to enforce good passphrases. Users will soon
355 figure up ways to bypass such a policy. A better policy is to
356 educate users on good security behavior and optionally to run a
357 passphrase cracker regularly on all users passphrases to catch
358 the very simple ones.
359 --max-passphrase-days n
362 Ask the user to change the passphrase if n days have passed
363 since the last change. With --enforce-passphrase-constraints
364 set the user may not bypass this check.
365 --enable-passphrase-history
368 This option does nothing yet.
369 --pinentry-program filename
372 Use program filename as the PIN entry. The default is installa‐
373 tion dependent.
374 --pinentry-touch-file filename
377 By default the filename of the socket gpg-agent is listening for
378 requests is passed to Pinentry, so that it can touch that file
379 before exiting (it does this only in curses mode). This option
380 changes the file passed to Pinentry to filename. The special
381 name /dev/null may be used to completely disable this feature.
382 Note that Pinentry will not create that file, it will only
383 change the modification and access time.
384 --scdaemon-program filename
388 Use program filename as the Smartcard daemon. The default is
389 installation dependent and can be shown with the gpgconf com‐
390 mand.
391 --disable-scdaemon
394 Do not make use of the scdaemon tool. This option has the
395 effect of disabling the ability to do smartcard operations.
396 Note, that enabling this option at runtime does not kill an
397 already forked scdaemon.
398 --disable-check-own-socket
401 gpg-agent employs a periodic self-test to detect a stolen
402 socket. This usually means a second instance of gpg-agent has
403 taken over the socket and gpg-agent will then terminate itself.
404 This option may be used to disable this self-test for debugging
405 purposes.
406 --use-standard-socket
409 --no-use-standard-socket
411 By enabling this option gpg-agent will listen on the socket
412 named ‘S.gpg-agent’, located in the home directory, and not cre‐
413 ate a random socket below a temporary directory. Tools connect‐
414 ing to gpg-agent should first try to connect to the socket given
415 in environment variable GPG_AGENT_INFO and then fall back to
416 this socket. This option may not be used if the home directory
417 is mounted on a remote file system which does not support spe‐
418 cial files like fifos or sockets. Note, that --use-standard-
419 socket is the default on all systems since GnuPG 2.1. Note,
420 that --use-standard-socket is the default on Windows systems.
421 The default may be changed at build time. It is possible to
422 test at runtime whether the agent has been configured for use
423 with the standard socket by issuing the command gpg-agent --use-
424 standard-socket-p which returns success if the standard socket
425 option has been enabled.
426 --display string
429 --ttyname string
431 --ttytype string
433 --lc-ctype string
435 --lc-messages string
437 --xauthority string
439 These options are used with the server mode to pass localization
440 information.
441 --keep-tty
444 --keep-display
446 Ignore requests to change the current tty or X window system's
447 DISPLAY variable respectively. This is useful to lock the
448 pinentry to pop up at the tty or display you started the agent.
449 --enable-ssh-support
453 Enable the OpenSSH Agent protocol.
455 In this mode of operation, the agent does not only implement the
457 gpg-agent protocol, but also the agent protocol used by OpenSSH
458 (through a separate socket). Consequently, it should be possi‐
459 ble to use the gpg-agent as a drop-in replacement for the well
460 known ssh-agent.
461 SSH Keys, which are to be used through the agent, need to be
463 added to the gpg-agent initially through the ssh-add utility.
464 When a key is added, ssh-add will ask for the password of the
465 provided key file and send the unprotected key material to the
466 agent; this causes the gpg-agent to ask for a passphrase, which
467 is to be used for encrypting the newly received key and storing
468 it in a gpg-agent specific directory.
469 Once a key has been added to the gpg-agent this way, the gpg-
471 agent will be ready to use the key.
472 Note: in case the gpg-agent receives a signature request, the
474 user might need to be prompted for a passphrase, which is neces‐
475 sary for decrypting the stored key. Since the ssh-agent proto‐
476 col does not contain a mechanism for telling the agent on which
477 display/terminal it is running, gpg-agent's ssh-support will use
478 the TTY or X display where gpg-agent has been started. To
479 switch this display to the current one, the following command
480 may be used:
481 gpg-connect-agent updatestartuptty /bye
483 Although all GnuPG components try to start the gpg-agent as needed,
485 this is not possible for the ssh support because ssh does not know
486 about it. Thus if no GnuPG tool which accesses the agent has been run,
487 there is no guarantee that ssh is abale to use gpg-agent for authenti‐
488 cation. To fix this you may start gpg-agent if needed using this sim‐
489 ple command:
490 gpg-connect-agent /bye
492 Adding the --verbose shows the progress of starting the agent.
494 All the long options may also be given in the configuration file after
497 stripping off the two leading dashes.
498
502 The usual way to invoke gpg-agent is
503 $ eval $(gpg-agent --daemon)
505 An alternative way is by replacing ssh-agent with gpg-agent. If for
507 example ssh-agent is started as part of the Xsession initialization,
508 you may simply replace ssh-agent by a script like:
509 #!/bin/sh
511 exec /usr/local/bin/gpg-agent --enable-ssh-support --daemon \
513 --write-env-file ${HOME}/.gpg-agent-info "$@"
514 and add something like (for Bourne shells)
517 if [ -f "${HOME}/.gpg-agent-info" ]; then
519 . "${HOME}/.gpg-agent-info"
520 export GPG_AGENT_INFO
521 export SSH_AUTH_SOCK
522 fi
523 to your shell initialization file (e.g. ‘~/.bashrc’).
526
530 There are a few configuration files needed for the operation of the
531 agent. By default they may all be found in the current home directory
532 (see: [option --homedir]).
533 gpg-agent.conf
537 This is the standard configuration file read by gpg-agent on
538 startup. It may contain any valid long option; the leading
539 two dashes may not be entered and the option may not be abbre‐
540 viated.
541 This file is also read after a SIGHUP however only a few
542 options will actually have an effect. This default name may
543 be
544 changed on the command line (see: [option --options]).
545 You should backup this file.
546 trustlist.txt
549 This is the list of trusted keys. You should backup this
550 file.
551 Comment lines, indicated by a leading hash mark, as well as
553 empty
554 lines are ignored. To mark a key as trusted you need to enter
555 its
556 fingerprint followed by a space and a capital letter S.
557 Colons
558 may optionally be used to separate the bytes of a fingerprint;
559 this
560 allows to cut and paste the fingerprint from a key listing
561 output. If
562 the line is prefixed with a ! the key is explicitly marked as
563 not trusted.
564 Here is an example where two keys are marked as ultimately
566 trusted
567 and one as not trusted:
568 .RS 2
570 # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
571 A6935DD34EF3087973C706FC311AA2CCF733765B S
572 # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
574 DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S
575 # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
577 !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
578 .fi
579 Before entering a key into this file, you need to ensure its
581 authenticity. How to do this depends on your organisation; your
582 administrator might have already entered those keys which are deemed
583 trustworthy enough into this file. Places where to look for the
584 fingerprint of a root certificate are letters received from the CA or
585 the website of the CA (after making 100% sure that this is indeed the
586 website of that CA). You may want to consider allowing interactive
587 updates of this file by using the see: [option --allow-mark-trusted].
588 This is however not as secure as maintaining this file manually. It is
589 even advisable to change the permissions to read-only so that this file
590 can't be changed inadvertently.
591 As a special feature a line include-default will include a global
593 list of trusted certificates (e.g. ‘/etc/gnupg/trustlist.txt’).
594 This global list is also used if the local list is not available.
595 It is possible to add further flags after the S for use by the
597 caller:
598 relax Relax checking of some root certificate requirements. As of now this
602 flag allows the use of root certificates with a missing basicConstraints
603 attribute (despite that it is a MUST for CA certificates) and disables
604 CRL checking for the root certificate.
605 cm If validation of a certificate finally issued by a CA with this flag set
608 fails, try again using the chain validation model.
609 sshcontrol
614 This file is used when support for the secure shell agent protocol has
615 been enabled (see: [option --enable-ssh-support]). Only keys present in
616 this file are used in the SSH protocol. You should backup this file.
617 The ssh-add tool may be used to add new entries to this file;
619 you may also add them manually. Comment lines, indicated by a leading
620 hash mark, as well as empty lines are ignored. An entry starts with
621 optional whitespace, followed by the keygrip of the key given as 40 hex
622 digits, optionally followed by the caching TTL in seconds and another
623 optional field for arbitrary flags. A non-zero TTL overrides the global
624 default as set by --default-cache-ttl-ssh.
625 The only flag support is confirm. If this flag is found for a
627 key, each use of the key will pop up a pinentry to confirm the use of
628 that key. The flag is automatically set if a new key was loaded into
629 gpg-agent using the option -c of the ssh-add
630 command.
631 The keygrip may be prefixed with a ! to disable an entry entry.
633 The following example lists exactly one key. Note that keys available
635 through a OpenPGP smartcard in the active smartcard reader are
636 implicitly added to this list; i.e. there is no need to list them.
637 .RS 2
639 # Key added on: 2011-07-20 20:38:46
640 # Fingerprint: 5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
641 34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
642 .fi
643 private-keys-v1.d/
646 This is the directory where gpg-agent stores the private keys. Each
648 key is stored in a file with the name made up of the keygrip and the
649 suffix ‘key’. You should backup all files in this directory
650 and take great care to keep this backup closed away.
651 Note that on larger installations, it is useful to put predefined
655 files into the directory ‘/etc/skel/.gnupg/’ so that newly created
656 users start up with a working configuration. For existing users the
657 a small helper script is provided to create these files (see: [addgnupghome]).
658
664 A running gpg-agent may be controlled by signals, i.e. using the kill
665 command to send a signal to the process.
666 Here is a list of supported signals:
668 SIGHUP This signal flushes all cached passphrases and if the program
672 has been started with a configuration file, the configuration
673 file is read again. Only certain options are honored: quiet,
674 verbose, debug, debug-all, debug-level, no-grab, pinentry-pro‐
675 gram, default-cache-ttl, max-cache-ttl, ignore-cache-for-sign‐
676 ing, allow-mark-trusted, disable-scdaemon, and disable-check-
677 own-socket. scdaemon-program is also supported but due to the
678 current implementation, which calls the scdaemon only once, it
679 is not of much use unless you manually kill the scdaemon.
680 SIGTERM
684 Shuts down the process but waits until all current requests are
685 fulfilled. If the process has received 3 of these signals and
686 requests are still pending, a shutdown is forced.
687 SIGINT Shuts down the process immediately.
690 SIGUSR1
693 Dump internal information to the log file.
694 SIGUSR2
697 This signal is used for internal purposes.
698
703 gpg2(1), gpgsm(1), gpg-connect-agent(1), scdaemon(1)
704 The full documentation for this tool is maintained as a Texinfo manual.
706 If GnuPG and the info program are properly installed at your site, the
707 command
708 info gnupg
710 should give you access to the complete manual including a menu struc‐
712 ture and an index.
713GnuPG 2.0.22 2018-07-13 GPG-AGENT(1)