1GPG-AGENT(1)                 GNU Privacy Guard 2.2                GPG-AGENT(1)
2
3
4

NAME

6       gpg-agent - Secret key management for GnuPG
7

SYNOPSIS

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
14

DESCRIPTION

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
20       The agent is automatically started on demand by gpg, gpgsm, gpgconf, or
21       gpg-connect-agent.   Thus  there is no reason to start it manually.  In
22       case you want to use the included Secure Shell Agent you may start  the
23       agent using:
24
25
26         gpg-connect-agent /bye
27
28
29       If  you want to manually terminate the currently-running agent, you can
30       safely do so with:
31
32         gpgconf --kill gpg-agent
33
34
35       You should always add the following lines to your .bashrc  or  whatever
36       initialization file is used for all shell invocations:
37
38         GPG_TTY=$(tty)
39         export GPG_TTY
40
41
42       It is important that this environment variable always reflects the out‐
43       put of the tty command.  For W32 systems this option is not required.
44
45       Please make sure that a proper pinentry program has been installed  un‐
46       der  the default filename (which is system dependent) or use the option
47       pinentry-program to specify the full name of that program.  It is often
48       useful  to  install a symbolic link from the actual used pinentry (e.g.
49/usr/bin/pinentry-gtk’) to the  expected  one  (e.g.  ‘/usr/bin/pinen‐
50       try’).
51
52
53
54

COMMANDS

56       Commands  are  not  distinguished from options except for the fact that
57       only one command is allowed.
58
59
60       --version
61              Print the program version and licensing information.  Note  that
62              you cannot abbreviate this command.
63
64
65       --help
66       -h     Print  a  usage message summarizing the most useful command-line
67              options.  Note that you cannot abbreviate this command.
68
69
70       --dump-options
71              Print a list of all available options and commands.   Note  that
72              you cannot abbreviate this command.
73
74
75       --server
76              Run  in server mode and wait for commands on the stdin.  The de‐
77              fault mode is to create a socket and listen for commands there.
78
79
80       --daemon [command line]
81              Start the gpg-agent as a daemon; that is,  detach  it  from  the
82              console and run it in the background.
83
84              As  an  alternative  you  may create a new process as a child of
85              gpg-agent: gpg-agent --daemon /bin/sh.  This way you get  a  new
86              shell  with  the environment setup properly; after you exit from
87              this shell, gpg-agent terminates within a few seconds.
88
89
90       --supervised
91              Run in the foreground, sending logs by default  to  stderr,  and
92              listening  on  provided  file descriptors, which must already be
93              bound to listening sockets.  This command is useful when running
94              under  systemd  or  other  similar  process supervision schemes.
95              This option is not supported on Windows.
96
97              In --supervised mode, different file descriptors can be provided
98              for  use  as different socket types (e.g. ssh, extra) as long as
99              they are identified in the environment  variable  LISTEN_FDNAMES
100              (see  sd_listen_fds(3)  on some Linux distributions for more in‐
101              formation on this convention).
102

OPTIONS

104       Options may either be used on the command line or, after stripping  off
105       the two leading dashes, in the configuration file.
106
107
108
109
110       --options file
111              Reads  configuration  from file instead of from the default per-
112              user configuration file.   The  default  configuration  file  is
113              named  ‘gpg-agent.conf’  and  expected in the ‘.gnupg’ directory
114              directly below the home directory of the user.  This  option  is
115              ignored if used in an options file.
116
117
118
119       --homedir dir
120              Set the name of the home directory to dir. If this option is not
121              used, the home directory defaults to  ‘~/.gnupg’.   It  is  only
122              recognized  when  given  on the command line.  It also overrides
123              any home  directory  stated  through  the  environment  variable
124GNUPGHOME’ or (on Windows systems) by means of the Registry en‐
125              try HKCU\Software\GNU\GnuPG:HomeDir.
126
127              On Windows systems it is possible to install GnuPG as a portable
128              application.  In this case only this command line option is con‐
129              sidered, all other ways to set a home directory are ignored.
130
131              To install GnuPG as a portable application under Windows, create
132              an  empty  file named ‘gpgconf.ctl’ in the same directory as the
133              tool ‘gpgconf.exe’.  The root of the installation is  then  that
134              directory;  or, if ‘gpgconf.exe’ has been installed directly be‐
135              low a directory named ‘bin’, its  parent  directory.   You  also
136              need  to  make sure that the following directories exist and are
137              writable:    ‘ROOT/home’    for    the    GnuPG     home     and
138ROOT/var/cache/gnupg’ for internal cache files.
139
140
141
142       -v
143       --verbose
144              Outputs  additional information while running.  You can increase
145              the verbosity by giving several verbose commands  to  gpg-agent,
146              such as ‘-vv’.
147
148
149       -q
150       --quiet
151              Try to be as quiet as possible.
152
153
154       --batch
155              Don't  invoke  a  pinentry or do any other thing requiring human
156              interaction.
157
158
159       --faked-system-time epoch
160              This option is only useful for testing; it sets the system  time
161              back  or  forth  to epoch which is the number of seconds elapsed
162              since the year 1970.
163
164
165       --debug-level level
166              Select the debug level for investigating problems. level may  be
167              a numeric value or a keyword:
168
169
170              none   No  debugging at all.  A value of less than 1 may be used
171                     instead of the keyword.
172
173              basic  Some basic debug messages.  A value between 1 and  2  may
174                     be used instead of the keyword.
175
176              advanced
177                     More verbose debug messages.  A value between 3 and 5 may
178                     be used instead of the keyword.
179
180              expert Even more detailed messages.  A value between 6 and 8 may
181                     be used instead of the keyword.
182
183              guru   All  of  the  debug messages you can get. A value greater
184                     than 8 may be used instead of the keyword.  The  creation
185                     of  hash  tracing files is only enabled if the keyword is
186                     used.
187
188       How these messages are mapped to the  actual  debugging  flags  is  not
189       specified  and may change with newer releases of this program. They are
190       however carefully selected to best aid in debugging.
191
192
193       --debug flags
194              Set debug flags.  All flags are or-ed and flags may be given  in
195              C  syntax  (e.g.  0x0042)  or  as a comma separated list of flag
196              names.  To get a list of all supported  flags  the  single  word
197              "help" can be used. This option is only useful for debugging and
198              the behavior may change at any time without notice.
199
200
201       --debug-all
202              Same as --debug=0xffffffff
203
204
205       --debug-wait n
206              When running in server mode, wait n seconds before entering  the
207              actual  processing  loop  and print the pid.  This gives time to
208              attach a debugger.
209
210
211       --debug-quick-random
212              This option inhibits the use of the very secure  random  quality
213              level (Libgcrypt’s GCRY_VERY_STRONG_RANDOM) and degrades all re‐
214              quest down to standard random quality.   It  is  only  used  for
215              testing  and should not be used for any production quality keys.
216              This option is only effective when given on the command line.
217
218              On GNU/Linux, another way to quickly generate insecure  keys  is
219              to use rngd to fill the kernel's entropy pool with lower quality
220              random data.  rngd is typically provided by the rng-tools  pack‐
221              age.  It can be run as follows: ‘sudo rngd -f -r /dev/urandom’.
222
223
224       --debug-pinentry
225              This  option  enables  extra debug information pertaining to the
226              Pinentry.  As of now it is only  useful  when  used  along  with
227              --debug 1024.
228
229
230       --no-detach
231              Don't  detach the process from the console.  This is mainly use‐
232              ful for debugging.
233
234
235       -s
236       --sh
237       -c
238       --csh  Format the info output in daemon mode for use with the  standard
239              Bourne  shell  or  the  C-shell respectively.  The default is to
240              guess it based on the environment variable SHELL which  is  cor‐
241              rect in almost all cases.
242
243
244
245       --grab
246       --no-grab
247              Tell  the  pinentry to grab the keyboard and mouse.  This option
248              should be used on X-Servers to avoid X-sniffing attacks. Any use
249              of  the  option  --grab overrides an used option --no-grab.  The
250              default is --no-grab.
251
252
253
254       --log-file file
255              Append all logging output to file.  This is very helpful in see‐
256              ing  what  the  agent  actually  does. Use ‘socket://’ to log to
257              socket.  If neither a log file nor a  log  file  descriptor  has
258              been  set  on  a Windows platform, the Registry entry HKCU\Soft‐
259              ware\GNU\GnuPG:DefaultLogFile, if set, is used  to  specify  the
260              logging output.
261
262
263
264
265       --no-allow-mark-trusted
266              Do not allow clients to mark keys as trusted, i.e. put them into
267              the ‘trustlist.txt’ file.  This makes it harder for users to in‐
268              advertently accept Root-CA keys.
269
270
271
272       --allow-preset-passphrase
273              This  option allows the use of gpg-preset-passphrase to seed the
274              internal cache of gpg-agent with passphrases.
275
276
277
278       --no-allow-loopback-pinentry
279
280       --allow-loopback-pinentry
281              Disallow or allow clients to use the loopback pinentry features;
282              see the option pinentry-mode for details.  Allow is the default.
283
284              The --force option of the Assuan command DELETE_KEY is also con‐
285              trolled by this option: The option  is  ignored  if  a  loopback
286              pinentry is disallowed.
287
288
289       --no-allow-external-cache
290              Tell Pinentry not to enable features which use an external cache
291              for passphrases.
292
293              Some desktop environments prefer to unlock all credentials  with
294              one  master password and may have installed a Pinentry which em‐
295              ploys an additional external cache to implement such  a  policy.
296              By  using this option the Pinentry is advised not to make use of
297              such a cache and instead always ask the user for  the  requested
298              passphrase.
299
300
301       --allow-emacs-pinentry
302              Tell  Pinentry  to allow features to divert the passphrase entry
303              to a running Emacs instance.  How this is  exactly  handled  de‐
304              pends on the version of the used Pinentry.
305
306
307       --ignore-cache-for-signing
308              This  option  will let gpg-agent bypass the passphrase cache for
309              all signing operation.  Note that there is  also  a  per-session
310              option  to  control  this  behavior but this command line option
311              takes precedence.
312
313
314       --default-cache-ttl n
315              Set the time a cache entry is valid to n seconds.   The  default
316              is  600  seconds.   Each time a cache entry is accessed, the en‐
317              try's timer is reset.  To set an entry's maximum  lifetime,  use
318              max-cache-ttl.  Note that a cached passphrase may not be evicted
319              immediately from memory if no client requests a cache operation.
320              This  is  due to an internal housekeeping function which is only
321              run every few seconds.
322
323
324       --default-cache-ttl-ssh n
325              Set the time a cache entry used for SSH keys is valid to n  sec‐
326              onds.   The default is 1800 seconds.  Each time a cache entry is
327              accessed, the entry's timer is reset.  To set an entry's maximum
328              lifetime, use max-cache-ttl-ssh.
329
330
331       --max-cache-ttl n
332              Set the maximum time a cache entry is valid to n seconds.  After
333              this time a cache entry will be expired even if it has been  ac‐
334              cessed  recently  or  has  been set using gpg-preset-passphrase.
335              The default is 2 hours (7200 seconds).
336
337
338       --max-cache-ttl-ssh n
339              Set the maximum time a cache entry used for SSH keys is valid to
340              n  seconds.   After this time a cache entry will be expired even
341              if it has been accessed recently or has been set using  gpg-pre‐
342              set-passphrase.  The default is 2 hours (7200 seconds).
343
344
345       --enforce-passphrase-constraints
346              Enforce  the  passphrase constraints by not allowing the user to
347              bypass them using the ``Take it anyway'' button.
348
349
350       --min-passphrase-len n
351              Set the minimal length of a passphrase.   When  entering  a  new
352              passphrase  shorter than this value a warning will be displayed.
353              Defaults to 8.
354
355
356       --min-passphrase-nonalpha n
357              Set the minimal number of digits or special characters  required
358              in  a passphrase.  When entering a new passphrase with less than
359              this number of digits or special characters a  warning  will  be
360              displayed.  Defaults to 1.
361
362
363       --check-passphrase-pattern file
364       --check-sym-passphrase-pattern file
365              Check  the  passphrase  against the pattern given in file.  When
366              entering a new passphrase matching one of these pattern a  warn‐
367              ing will be displayed.  If file does not contain any slashes and
368              does not start with "~/" it is searched in the system configura‐
369              tion  directory  (‘/etc/gnupg’).   The default is not to use any
370              pattern file.  The second version of this option  is  only  used
371              when  creating a new symmetric key to allow the use of different
372              patterns for such passphrases.
373
374              Security note: It is known that checking a passphrase against  a
375              list  of  pattern  or  even against a complete dictionary is not
376              very effective to enforce good  passphrases.   Users  will  soon
377              figure  up  ways to bypass such a policy.  A better policy is to
378              educate users on good security behavior and optionally to run  a
379              passphrase  cracker  regularly on all users passphrases to catch
380              the very simple ones.
381
382
383       --max-passphrase-days n
384              Ask the user to change the passphrase  if  n  days  have  passed
385              since  the  last  change.  With --enforce-passphrase-constraints
386              set the user may not bypass this check.
387
388
389       --enable-passphrase-history
390              This option does nothing yet.
391
392
393       --pinentry-invisible-char char
394              This option asks the Pinentry to use char for displaying  hidden
395              characters.   char must be one character UTF-8 string.  A Pinen‐
396              try may or may not honor this request.
397
398
399       --pinentry-timeout n
400              This option asks the Pinentry to timeout after n seconds with no
401              user input.  The default value of 0 does not ask the pinentry to
402              timeout, however a Pinentry may  use  its  own  default  timeout
403              value  in  this  case.  A Pinentry may or may not honor this re‐
404              quest.
405
406
407       --pinentry-formatted-passphrase
408              This option asks the Pinentry to  enable  passphrase  formatting
409              when  asking  the  user  for a new passphrase and masking of the
410              passphrase is turned off.
411
412              If passphrase formatting is enabled, then all non-breaking space
413              characters are stripped from the entered passphrase.  Passphrase
414              formatting is mostly useful in combination with passphrases gen‐
415              erated  with  the  GENPIN feature of some Pinentries.  Note that
416              such a generated passphrase, if not modified by the user,  skips
417              all  passphrase  constraints  checking  because such constraints
418              would actually weaken the generated passphrase.
419
420
421       --pinentry-program filename
422              Use program filename as the PIN entry.  The default is installa‐
423              tion  dependent.  With the default configuration the name of the
424              default pinentry is ‘pinentry’; if that file does not exist  but
425              a ‘pinentry-basic’ exist the latter is used.
426
427              On  a  Windows platform the default is to use the first existing
428              program      from      this      list:       ‘bin\pinentry.exe’,
429..\Gpg4win\bin\pinentry.exe’,        ‘..\Gpg4win\pinentry.exe’,
430..\GNU\GnuPG\pinentry.exe’,          ‘..\GNU\bin\pinentry.exe’,
431bin\pinentry-basic.exe’  where  the  file names are relative to
432              the GnuPG installation directory.
433
434
435
436       --pinentry-touch-file filename
437              By default the filename of the socket gpg-agent is listening for
438              requests  is  passed to Pinentry, so that it can touch that file
439              before exiting (it does this only in curses mode).  This  option
440              changes  the  file  passed to Pinentry to filename.  The special
441              name /dev/null may be used to completely disable  this  feature.
442              Note  that  Pinentry  will  not  create  that file, it will only
443              change the modification and access time.
444
445
446
447       --scdaemon-program filename
448              Use program filename as the Smartcard daemon.   The  default  is
449              installation  dependent  and  can be shown with the gpgconf com‐
450              mand.
451
452
453       --disable-scdaemon
454              Do not make use of the scdaemon tool.  This option has  the  ef‐
455              fect of disabling the ability to do smartcard operations.  Note,
456              that enabling this option at runtime does not  kill  an  already
457              forked scdaemon.
458
459
460       --disable-check-own-socket
461              gpg-agent  employs  a  periodic  self-test  to  detect  a stolen
462              socket.  This usually means a second instance of  gpg-agent  has
463              taken  over the socket and gpg-agent will then terminate itself.
464              This option may be used to disable this self-test for  debugging
465              purposes.
466
467
468       --use-standard-socket
469       --no-use-standard-socket
470       --use-standard-socket-p
471              Since  GnuPG  2.1 the standard socket is always used.  These op‐
472              tions have no more effect.  The  command  gpg-agent  --use-stan‐
473              dard-socket-p will thus always return success.
474
475
476       --display string
477       --ttyname string
478       --ttytype string
479       --lc-ctype string
480       --lc-messages string
481       --xauthority string
482              These options are used with the server mode to pass localization
483              information.
484
485
486       --keep-tty
487       --keep-display
488              Ignore requests to change the current tty or X  window  system's
489              DISPLAY  variable  respectively.   This  is  useful  to lock the
490              pinentry to pop up at the tty or display you started the agent.
491
492
493       --listen-backlog n
494              Set the size of the queue for pending connections.  The  default
495              is 64.
496
497
498
499       --extra-socket name
500              The  extra socket is created by default, you may use this option
501              to change the name of the socket.  To disable  the  creation  of
502              the socket use ``none'' or ``/dev/null'' for name.
503
504              Also listen on native gpg-agent connections on the given socket.
505              The intended use for this extra socket is to setup a Unix domain
506              socket  forwarding  from  a remote machine to this socket on the
507              local machine.  A gpg running on the  remote  machine  may  then
508              connect  to  the local gpg-agent and use its private keys.  This
509              enables decrypting or signing data on a remote  machine  without
510              exposing the private keys to the remote machine.
511
512
513       --enable-extended-key-format
514       --disable-extended-key-format
515              Since  version  2.3 keys are created in the extended private key
516              format.  Changing the passphrase of a key will also convert  the
517              key  to that new format.  This new key format is supported since
518              GnuPG version 2.1.12 and thus there should be no need to disable
519              it.  The disable option allows to revert to the old behavior for
520              new keys; be aware that keys are never migrated back to the  old
521              format.   However if the enable option has been used the disable
522              option won't have an effect.  The advantage of the extended pri‐
523              vate  key  format  is  that it is text based and can carry addi‐
524              tional meta data.
525
526
527
528       --enable-ssh-support
529       --enable-putty-support
530
531              The OpenSSH Agent protocol is always enabled, but gpg-agent will
532              only set the SSH_AUTH_SOCK variable if this flag is given.
533
534              In this mode of operation, the agent does not only implement the
535              gpg-agent protocol, but also the agent protocol used by  OpenSSH
536              (through  a separate socket).  Consequently, it should be possi‐
537              ble to use the gpg-agent as a drop-in replacement for  the  well
538              known ssh-agent.
539
540              SSH  Keys,  which  are  to be used through the agent, need to be
541              added to the gpg-agent initially through  the  ssh-add  utility.
542              When  a  key  is added, ssh-add will ask for the password of the
543              provided key file and send the unprotected key material  to  the
544              agent;  this causes the gpg-agent to ask for a passphrase, which
545              is to be used for encrypting the newly received key and  storing
546              it in a gpg-agent specific directory.
547
548              Once  a  key  has been added to the gpg-agent this way, the gpg-
549              agent will be ready to use the key.
550
551              Note: in case the gpg-agent receives a  signature  request,  the
552              user might need to be prompted for a passphrase, which is neces‐
553              sary for decrypting the stored key.  Since the ssh-agent  proto‐
554              col  does not contain a mechanism for telling the agent on which
555              display/terminal it is running, gpg-agent's ssh-support will use
556              the  TTY  or  X  display  where  gpg-agent has been started.  To
557              switch this display to the current one,  the  following  command
558              may be used:
559
560         gpg-connect-agent updatestartuptty /bye
561
562       Although  all  GnuPG  components  try to start the gpg-agent as needed,
563       this is not possible for the ssh support  because  ssh  does  not  know
564       about it.  Thus if no GnuPG tool which accesses the agent has been run,
565       there is no guarantee that ssh is able to use gpg-agent for authentica‐
566       tion.   To fix this you may start gpg-agent if needed using this simple
567       command:
568
569         gpg-connect-agent /bye
570
571       Adding the --verbose shows the progress of starting the agent.
572
573       The --enable-putty-support is only available under Windows  and  allows
574       the  use of gpg-agent with the ssh implementation putty.  This is simi‐
575       lar to the regular ssh-agent support but makes use of  Windows  message
576       queue as required by putty.
577
578
579
580       --ssh-fingerprint-digest
581
582              Select  the  digest  algorithm  used to compute ssh fingerprints
583              that are communicated to the user,  e.g.  in  pinentry  dialogs.
584              OpenSSH  has  transitioned  from  using  MD5  to the more secure
585              SHA256.
586
587
588
589       --auto-expand-secmem n
590              Allow Libgcrypt to expand its secure memory  area  as  required.
591              The  optional value n is a non-negative integer with a suggested
592              size in bytes of each additionally allocated secure memory area.
593              The  value  is rounded up to the next 32 KiB; usual C style pre‐
594              fixes are allowed.  For an heavy loaded gpg-agent with many con‐
595              current connection this option avoids sign or decrypt errors due
596              to out of secure memory error returns.
597
598
599       --s2k-calibration milliseconds
600              Change the default calibration time to milliseconds.  The  given
601              value  is  capped at 60 seconds; a value of 0 resets to the com‐
602              piled-in default.  This option is re-read on a SIGHUP  (or  gpg‐
603              conf  --reload  gpg-agent)  and  the  S2K count is then re-cali‐
604              brated.
605
606
607       --s2k-count n
608              Specify the iteration count  used  to  protect  the  passphrase.
609              This option can be used to override the auto-calibration done by
610              default.  The auto-calibration computes a count  which  requires
611              by  default 100ms to mangle a given passphrase.  See also --s2k-
612              calibration.
613
614              To view the actually used iteration count and  the  milliseconds
615              required for an S2K operation use:
616
617         gpg-connect-agent 'GETINFO s2k_count' /bye
618         gpg-connect-agent 'GETINFO s2k_time' /bye
619
620       To view the auto-calibrated count use:
621
622         gpg-connect-agent 'GETINFO s2k_count_cal' /bye
623
624
625

EXAMPLES

627       It  is  important to set the environment variable GPG_TTY in your login
628       shell, for example in the ‘~/.bashrc’ init script:
629
630           export GPG_TTY=$(tty)
631
632       If you enabled the Ssh Agent Support, you also need to tell  ssh  about
633       it by adding this to your init script:
634
635         unset SSH_AGENT_PID
636         if [ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]; then
637           export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
638         fi
639
640
641
642

FILES

644       There  are  a  few  configuration files needed for the operation of the
645       agent. By default they may all be found in the current  home  directory
646       (see: [option --homedir]).
647
648
649
650       gpg-agent.conf
651                This is the standard configuration file read by gpg-agent on
652                startup.  It may contain any valid long option; the leading
653                two dashes may not be entered and the option may not be abbre‐
654              viated.
655                This file is also read after a SIGHUP however only a few
656                options will actually have an effect.  This default  name  may
657              be
658                changed on the command line (see: [option --options]).
659                You should backup this file.
660
661
662       trustlist.txt
663                This  is  the  list  of  trusted keys.  You should backup this
664              file.
665
666                Comment lines, indicated by a leading hash mark,  as  well  as
667              empty
668                lines are ignored.  To mark a key as trusted you need to enter
669              its
670                fingerprint followed by  a  space  and  a  capital  letter  S.
671              Colons
672                may optionally be used to separate the bytes of a fingerprint;
673              this
674                enables cutting and pasting the fingerprint from a key listing
675              output.  If
676                the line is prefixed with a ! the key is explicitly marked as
677                not trusted.
678
679                Here  is  an  example  where two keys are marked as ultimately
680              trusted
681                and one as not trusted:
682
683                  .RS 2
684                # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
685                A6935DD34EF3087973C706FC311AA2CCF733765B S
686
687                # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
688                DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S
689
690                # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
691                !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
692                .fi
693
694       Before entering a key into this file, you need to ensure its
695       authenticity.  How to do this depends on your organisation; your
696       administrator might have already entered those keys which are deemed
697       trustworthy enough into this file.  Places where to look for the
698       fingerprint of a root certificate are letters received from the CA or
699       the website of the CA (after making 100% sure that this is indeed the
700       website of that CA).  You may want to consider disallowing interactive
701       updates of this file by using the [option --no-allow-mark-trusted].
702       It might even be advisable to change the permissions to read-only so
703       that this file can't be changed inadvertently.
704
705       As a special feature a line include-default will include a global
706       list of trusted certificates (e.g. ‘/etc/gnupg/trustlist.txt’).
707       This global list is also used if the local list is not available.
708
709       It is possible to add further flags after the S for use by the
710       caller:
711
712
713
714              relax  Relax checking of some root certificate requirements.  As of now this
715                     flag allows the use of root certificates with a missing basicConstraints
716                     attribute (despite that it is a MUST for CA certificates) and disables
717                     CRL checking for the root certificate.
718
719
720              cm     If validation of a certificate finally issued by a CA with this flag set
721                     fails, try again using the chain validation model.
722
723
724
725
726       sshcontrol
727              This file is used when support for the secure shell agent protocol has
728              been enabled (see: [option --enable-ssh-support]). Only keys present in
729              this file are used in the SSH protocol.  You should backup this file.
730
731              The ssh-add tool may be used to add new entries to this file;
732              you may also add them manually.  Comment lines, indicated by a leading
733              hash mark, as well as empty lines are ignored.  An entry starts with
734              optional whitespace, followed by the keygrip of the key given as 40 hex
735              digits, optionally followed by the caching TTL in seconds and another
736              optional field for arbitrary flags.  A non-zero TTL overrides the global
737              default as set by --default-cache-ttl-ssh.
738
739              The only flag support is confirm.  If this flag is found for a
740              key, each use of the key will pop up a pinentry to confirm the use of
741              that key.  The flag is automatically set if a new key was loaded into
742              gpg-agent using the option -c of the ssh-add
743              command.
744
745              The keygrip may be prefixed with a ! to disable an entry.
746
747              The following example lists exactly one key.  Note that keys available
748              through a OpenPGP smartcard in the active smartcard reader are
749              implicitly added to this list; i.e. there is no need to list them.
750
751                # Key added on: 2011-07-20 20:38:46
752                # Fingerprint:  5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
753                34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
754
755
756       private-keys-v1.d/
757
758                This is the directory where gpg-agent stores the private keys.
759              Each
760                key  is  stored in a file with the name made up of the keygrip
761              and the
762                suffix ‘key’.  You should backup all files in this directory
763                and take great care to keep this backup closed away.
764
765
766
767       Note that on larger installations, it is useful to put predefined files
768       into the directory ‘/etc/skel/.gnupg’ so that newly created users start
769       up with a working configuration.  For existing users the a small helper
770       script is provided to create these files (see: [addgnupghome]).
771
772
773
774
775

SIGNALS

777       A  running  gpg-agent may be controlled by signals, i.e. using the kill
778       command to send a signal to the process.
779
780       Here is a list of supported signals:
781
782
783
784       SIGHUP This signal flushes all cached passphrases and  if  the  program
785              has  been  started  with a configuration file, the configuration
786              file is read again.  Only certain options  are  honored:  quiet,
787              verbose, debug, debug-all, debug-level, debug-pinentry, no-grab,
788              pinentry-program,  pinentry-invisible-char,   default-cache-ttl,
789              max-cache-ttl, ignore-cache-for-signing, s2k-count, no-allow-ex‐
790              ternal-cache, allow-emacs-pinentry, no-allow-mark-trusted,  dis‐
791              able-scdaemon,  and  disable-check-own-socket.  scdaemon-program
792              is also supported but due to the current  implementation,  which
793              calls  the  scdaemon only once, it is not of much use unless you
794              manually kill the scdaemon.
795
796
797
798       SIGTERM
799              Shuts down the process but waits until all current requests  are
800              fulfilled.   If  the process has received 3 of these signals and
801              requests are still pending, a shutdown is forced.
802
803
804       SIGINT Shuts down the process immediately.
805
806
807       SIGUSR1
808              Dump internal information to the log file.
809
810
811       SIGUSR2
812              This signal is used for internal purposes.
813
814

SEE ALSO

816       gpg(1), gpgsm(1), gpgconf(1), gpg-connect-agent(1), scdaemon(1)
817
818       The full documentation for this tool is maintained as a Texinfo manual.
819       If  GnuPG and the info program are properly installed at your site, the
820       command
821
822         info gnupg
823
824       should give you access to the complete manual including a  menu  struc‐
825       ture and an index.
826
827
828
829GnuPG 2.3.3                       2021-10-06                      GPG-AGENT(1)
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