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 --use-standard-socket
401 --no-use-standard-socket
403 By enabling this option gpg-agent will listen on the socket
404 named ‘S.gpg-agent’, located in the home directory, and not cre‐
405 ate a random socket below a temporary directory. Tools connect‐
406 ing to gpg-agent should first try to connect to the socket given
407 in environment variable GPG_AGENT_INFO and then fall back to
408 this socket. This option may not be used if the home directory
409 is mounted on a remote file system which does not support spe‐
410 cial files like fifos or sockets. Note, that --use-standard-
411 socket is the default on all systems since GnuPG 2.1. Note,
412 that --use-standard-socket is the default on Windows systems.
413 The default may be changed at build time. It is possible to
414 test at runtime whether the agent has been configured for use
415 with the standard socket by issuing the command gpg-agent --use-
416 standard-socket-p which returns success if the standard socket
417 option has been enabled.
418 --display string
421 --ttyname string
423 --ttytype string
425 --lc-ctype string
427 --lc-messages string
429 --xauthority string
431 These options are used with the server mode to pass localization
432 information.
433 --keep-tty
436 --keep-display
438 Ignore requests to change the current tty or X window system's
439 DISPLAY variable respectively. This is useful to lock the
440 pinentry to pop up at the tty or display you started the agent.
441 --enable-ssh-support
445 Enable the OpenSSH Agent protocol.
447 In this mode of operation, the agent does not only implement the
449 gpg-agent protocol, but also the agent protocol used by OpenSSH
450 (through a separate socket). Consequently, it should be possi‐
451 ble to use the gpg-agent as a drop-in replacement for the well
452 known ssh-agent.
453 SSH Keys, which are to be used through the agent, need to be
455 added to the gpg-agent initially through the ssh-add utility.
456 When a key is added, ssh-add will ask for the password of the
457 provided key file and send the unprotected key material to the
458 agent; this causes the gpg-agent to ask for a passphrase, which
459 is to be used for encrypting the newly received key and storing
460 it in a gpg-agent specific directory.
461 Once a key has been added to the gpg-agent this way, the gpg-
463 agent will be ready to use the key.
464 Note: in case the gpg-agent receives a signature request, the
466 user might need to be prompted for a passphrase, which is neces‐
467 sary for decrypting the stored key. Since the ssh-agent proto‐
468 col does not contain a mechanism for telling the agent on which
469 display/terminal it is running, gpg-agent's ssh-support will use
470 the TTY or X display where gpg-agent has been started. To
471 switch this display to the current one, the following command
472 may be used:
473 gpg-connect-agent updatestartuptty /bye
475 Although all GnuPG components try to start the gpg-agent as needed,
477 this is not possible for the ssh support because ssh does not know
478 about it. Thus if no GnuPG tool which accesses the agent has been run,
479 there is no guarantee that ssh is abale to use gpg-agent for authenti‐
480 cation. To fix this you may start gpg-agent if needed using this sim‐
481 ple command:
482 gpg-connect-agent /bye
484 Adding the --verbose shows the progress of starting the agent.
486 All the long options may also be given in the configuration file after
489 stripping off the two leading dashes.
490
494 The usual way to invoke gpg-agent is
495 $ eval $(gpg-agent --daemon)
497 An alternative way is by replacing ssh-agent with gpg-agent. If for
499 example ssh-agent is started as part of the Xsession initialization,
500 you may simply replace ssh-agent by a script like:
501 #!/bin/sh
503 exec /usr/local/bin/gpg-agent --enable-ssh-support --daemon \
505 --write-env-file ${HOME}/.gpg-agent-info "$@"
506 and add something like (for Bourne shells)
509 if [ -f "${HOME}/.gpg-agent-info" ]; then
511 . "${HOME}/.gpg-agent-info"
512 export GPG_AGENT_INFO
513 export SSH_AUTH_SOCK
514 fi
515 to your shell initialization file (e.g. ‘~/.bashrc’).
518
522 There are a few configuration files needed for the operation of the
523 agent. By default they may all be found in the current home directory
524 (see: [option --homedir]).
525 gpg-agent.conf
529 This is the standard configuration file read by gpg-agent on
530 startup. It may contain any valid long option; the leading
531 two dashes may not be entered and the option may not be abbre‐
532 viated.
533 This file is also read after a SIGHUP however only a few
534 options will actually have an effect. This default name may
535 be
536 changed on the command line (see: [option --options]).
537 You should backup this file.
538 trustlist.txt
541 This is the list of trusted keys. You should backup this
542 file.
543 Comment lines, indicated by a leading hash mark, as well as
545 empty
546 lines are ignored. To mark a key as trusted you need to enter
547 its
548 fingerprint followed by a space and a capital letter S.
549 Colons
550 may optionally be used to separate the bytes of a fingerprint;
551 this
552 allows to cut and paste the fingerprint from a key listing
553 output. If
554 the line is prefixed with a ! the key is explicitly marked as
555 not trusted.
556 Here is an example where two keys are marked as ultimately
558 trusted
559 and one as not trusted:
560 .RS 2
562 # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
563 A6935DD34EF3087973C706FC311AA2CCF733765B S
564 # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
566 DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S
567 # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
569 !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
570 .fi
571 Before entering a key into this file, you need to ensure its
573 authenticity. How to do this depends on your organisation; your
574 administrator might have already entered those keys which are deemed
575 trustworthy enough into this file. Places where to look for the
576 fingerprint of a root certificate are letters received from the CA or
577 the website of the CA (after making 100% sure that this is indeed the
578 website of that CA). You may want to consider allowing interactive
579 updates of this file by using the see: [option --allow-mark-trusted].
580 This is however not as secure as maintaining this file manually. It is
581 even advisable to change the permissions to read-only so that this file
582 can't be changed inadvertently.
583 As a special feature a line include-default will include a global
585 list of trusted certificates (e.g. ‘/etc/gnupg/trustlist.txt’).
586 This global list is also used if the local list is not available.
587 It is possible to add further flags after the S for use by the
589 caller:
590 relax Relax checking of some root certificate requirements. As of now this
594 flag allows the use of root certificates with a missing basicConstraints
595 attribute (despite that it is a MUST for CA certificates) and disables
596 CRL checking for the root certificate.
597 cm If validation of a certificate finally issued by a CA with this flag set
600 fails, try again using the chain validation model.
601 sshcontrol
606 This file is used when support for the secure shell agent protocol has
607 been enabled (see: [option --enable-ssh-support]). Only keys present in
608 this file are used in the SSH protocol. You should backup this file.
609 The ssh-add tool may be used to add new entries to this file;
611 you may also add them manually. Comment lines, indicated by a leading
612 hash mark, as well as empty lines are ignored. An entry starts with
613 optional whitespace, followed by the keygrip of the key given as 40 hex
614 digits, optionally followed by the caching TTL in seconds and another
615 optional field for arbitrary flags. A non-zero TTL overrides the global
616 default as set by --default-cache-ttl-ssh.
617 The only flag support is confirm. If this flag is found for a
619 key, each use of the key will pop up a pinentry to confirm the use of
620 that key. The flag is automatically set if a new key was loaded into
621 gpg-agent using the option -c of the ssh-add
622 command.
623 The keygrip may be prefixed with a ! to disable an entry entry.
625 The following example lists exactly one key. Note that keys available
627 through a OpenPGP smartcard in the active smartcard reader are
628 implicitly added to this list; i.e. there is no need to list them.
629 .RS 2
631 # Key added on: 2011-07-20 20:38:46
632 # Fingerprint: 5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
633 34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
634 .fi
635 private-keys-v1.d/
638 This is the directory where gpg-agent stores the private keys. Each
640 key is stored in a file with the name made up of the keygrip and the
641 suffix ‘key’. You should backup all files in this directory
642 and take great care to keep this backup closed away.
643 Note that on larger installations, it is useful to put predefined
647 files into the directory ‘/etc/skel/.gnupg/’ so that newly created
648 users start up with a working configuration. For existing users the
649 a small helper script is provided to create these files (see: [addgnupghome]).
650
656 A running gpg-agent may be controlled by signals, i.e. using the kill
657 command to send a signal to the process.
658 Here is a list of supported signals:
660 SIGHUP This signal flushes all cached passphrases and if the program
664 has been started with a configuration file, the configuration
665 file is read again. Only certain options are honored: quiet,
666 verbose, debug, debug-all, debug-level, no-grab, pinentry-pro‐
667 gram, default-cache-ttl, max-cache-ttl, ignore-cache-for-sign‐
668 ing, allow-mark-trusted and disable-scdaemon. scdaemon-program
669 is also supported but due to the current implementation, which
670 calls the scdaemon only once, it is not of much use unless you
671 manually kill the scdaemon.
672 SIGTERM
676 Shuts down the process but waits until all current requests are
677 fulfilled. If the process has received 3 of these signals and
678 requests are still pending, a shutdown is forced.
679 SIGINT Shuts down the process immediately.
682 SIGUSR1
685 Dump internal information to the log file.
686 SIGUSR2
689 This signal is used for internal purposes.
690
695 gpg2(1), gpgsm(1), gpg-connect-agent(1), scdaemon(1)
696 The full documentation for this tool is maintained as a Texinfo manual.
698 If GnuPG and the info program are properly installed at your site, the
699 command
700 info gnupg
702 should give you access to the complete manual including a menu struc‐
704 ture and an index.
705GnuPG 2.0.18 2011-09-20 GPG-AGENT(1)