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
46       under  the  default  filename  (which  is  system dependent) or use the
47       option pinentry-program to specify the full name of that  program.   It
48       is  often useful to install a symbolic link from the actual used pinen‐
49       try  (e.g.  ‘/usr/bin/pinentry-gtk’)  to   the   expected   one   (e.g.
50/usr/bin/pinentry’).
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
77              default mode is to create  a  socket  and  listen  for  commands
78              there.
79
80
81       --daemon [command line]
82              Start  the  gpg-agent  as  a daemon; that is, detach it from the
83              console and run it in the background.
84
85              As an alternative you may create a new process  as  a  child  of
86              gpg-agent:  gpg-agent  --daemon /bin/sh.  This way you get a new
87              shell with the environment setup properly; after you  exit  from
88              this shell, gpg-agent terminates within a few seconds.
89
90
91       --supervised
92              Run  in  the  foreground, sending logs by default to stderr, and
93              listening on provided file descriptors, which  must  already  be
94              bound to listening sockets.  This command is useful when running
95              under systemd or  other  similar  process  supervision  schemes.
96              This option is not supported on Windows.
97
98              In --supervised mode, different file descriptors can be provided
99              for use as different socket types (e.g. ssh, extra) as  long  as
100              they  are  identified in the environment variable LISTEN_FDNAMES
101              (see sd_listen_fds(3)  on  some  Linux  distributions  for  more
102              information on this convention).
103

OPTIONS

105       Options  may either be used on the command line or, after stripping off
106       the two leading dashes, in the configuration file.
107
108
109
110
111       --options file
112              Reads configuration from file instead of from the  default  per-
113              user  configuration  file.   The  default  configuration file is
114              named ‘gpg-agent.conf’ and expected in  the  ‘.gnupg’  directory
115              directly  below  the home directory of the user.  This option is
116              ignored if used in an options file.
117
118
119
120       --homedir dir
121              Set the name of the home directory to dir. If this option is not
122              used,  the  home  directory  defaults to ‘~/.gnupg’.  It is only
123              recognized when given on the command line.   It  also  overrides
124              any  home  directory  stated  through  the  environment variable
125GNUPGHOME’ or (on Windows systems) by  means  of  the  Registry
126              entry HKCU\Software\GNU\GnuPG:HomeDir.
127
128              On Windows systems it is possible to install GnuPG as a portable
129              application.  In this case only this command line option is con‐
130              sidered, all other ways to set a home directory are ignored.
131
132              To install GnuPG as a portable application under Windows, create
133              an empty file named ‘gpgconf.ctl’ in the same directory  as  the
134              tool  ‘gpgconf.exe’.   The root of the installation is then that
135              directory; or, if  ‘gpgconf.exe’  has  been  installed  directly
136              below  a  directory named ‘bin’, its parent directory.  You also
137              need to make sure that the following directories exist  and  are
138              writable:     ‘ROOT/home’     for    the    GnuPG    home    and
139ROOT/var/cache/gnupg’ for internal cache files.
140
141
142
143       -v
144
145       --verbose
146              Outputs additional information while running.  You can  increase
147              the  verbosity  by giving several verbose commands to gpg-agent,
148              such as '-vv'.
149
150
151       -q
152
153       --quiet
154              Try to be as quiet as possible.
155
156
157       --batch
158              Don't invoke a pinentry or do any other  thing  requiring  human
159              interaction.
160
161
162       --faked-system-time epoch
163              This  option is only useful for testing; it sets the system time
164              back or forth to epoch which is the number  of  seconds  elapsed
165              since the year 1970.
166
167
168       --debug-level level
169              Select  the debug level for investigating problems. level may be
170              a numeric value or a keyword:
171
172
173              none   No debugging at all.  A value of less than 1 may be  used
174                     instead of the keyword.
175
176              basic  Some  basic  debug messages.  A value between 1 and 2 may
177                     be used instead of the keyword.
178
179              advanced
180                     More verbose debug messages.  A value between 3 and 5 may
181                     be used instead of the keyword.
182
183              expert Even more detailed messages.  A value between 6 and 8 may
184                     be used instead of the keyword.
185
186              guru   All of the debug messages you can get.  A  value  greater
187                     than  8 may be used instead of the keyword.  The creation
188                     of hash tracing files is only enabled if the  keyword  is
189                     used.
190
191       How  these  messages  are  mapped  to the actual debugging flags is not
192       specified and may change with newer releases of this program. They  are
193       however carefully selected to best aid in debugging.
194
195
196       --debug flags
197              This  option  is  only useful for debugging and the behavior may
198              change at any time without notice.  FLAGS are  bit  encoded  and
199              may be given in usual C-Syntax. The currently defined bits are:
200
201
202              0 (1)  X.509 or OpenPGP protocol related data
203
204              1 (2)  values of big number integers
205
206              2 (4)  low level crypto operations
207
208              5 (32) memory allocation
209
210              6 (64) caching
211
212              7 (128)
213                     show memory statistics
214
215              9 (512)
216                     write hashed data to files named dbgmd-000*
217
218              10 (1024)
219                     trace Assuan protocol
220
221              12 (4096)
222                     bypass all certificate validation
223
224
225       --debug-all
226              Same as --debug=0xffffffff
227
228
229       --debug-wait n
230              When  running in server mode, wait n seconds before entering the
231              actual processing loop and print the pid.  This  gives  time  to
232              attach a debugger.
233
234
235       --debug-quick-random
236              This  option  inhibits the use of the very secure random quality
237              level (Libgcrypt’s  GCRY_VERY_STRONG_RANDOM)  and  degrades  all
238              request  down  to  standard random quality.  It is only used for
239              testing and should not be used for any production quality  keys.
240              This option is only effective when given on the command line.
241
242              On  GNU/Linux,  another way to quickly generate insecure keys is
243              to use rngd to fill the kernel's entropy pool with lower quality
244              random  data.  rngd is typically provided by the rng-tools pack‐
245              age.  It can be run as follows: 'sudo rngd -f -r /dev/urandom'.
246
247
248       --debug-pinentry
249              This option enables extra debug information  pertaining  to  the
250              Pinentry.   As  of  now  it  is only useful when used along with
251              --debug 1024.
252
253
254       --no-detach
255              Don't detach the process from the console.  This is mainly  use‐
256              ful for debugging.
257
258
259       -s
260       --sh
261       -c
262       --csh  Format  the info output in daemon mode for use with the standard
263              Bourne shell or the C-shell respectively.   The  default  is  to
264              guess  it  based on the environment variable SHELL which is cor‐
265              rect in almost all cases.
266
267
268
269       --grab
270       --no-grab
271              Tell the pinentry to grab the keyboard and mouse.   This  option
272              should be used on X-Servers to avoid X-sniffing attacks. Any use
273              of the option --grab overrides an used  option  --no-grab.   The
274              default is --no-grab.
275
276
277
278       --log-file file
279              Append all logging output to file.  This is very helpful in see‐
280              ing what the agent actually does.  Use  ‘socket://’  to  log  to
281              socket.   If  neither  a  log file nor a log file descriptor has
282              been set on a Windows platform, the  Registry  entry  HKCU\Soft‐
283              ware\GNU\GnuPG:DefaultLogFile,  if  set,  is used to specify the
284              logging output.
285
286
287
288
289       --no-allow-mark-trusted
290              Do not allow clients to mark keys as trusted, i.e. put them into
291              the  ‘trustlist.txt’  file.   This  makes it harder for users to
292              inadvertently accept Root-CA keys.
293
294
295
296       --allow-preset-passphrase
297              This option allows the use of gpg-preset-passphrase to seed  the
298              internal cache of gpg-agent with passphrases.
299
300
301
302       --no-allow-loopback-pinentry
303
304       --allow-loopback-pinentry
305              Disallow or allow clients to use the loopback pinentry features;
306              see the option pinentry-mode for details.  Allow is the default.
307
308              The --force option of the Assuan command DELETE_KEY is also con‐
309              trolled  by  this  option:  The  option is ignored if a loopback
310              pinentry is disallowed.
311
312
313       --no-allow-external-cache
314              Tell Pinentry not to enable features which use an external cache
315              for passphrases.
316
317              Some  desktop environments prefer to unlock all credentials with
318              one master password and may  have  installed  a  Pinentry  which
319              employs an additional external cache to implement such a policy.
320              By using this option the Pinentry is advised not to make use  of
321              such  a  cache and instead always ask the user for the requested
322              passphrase.
323
324
325       --allow-emacs-pinentry
326              Tell Pinentry to allow features to divert the  passphrase  entry
327              to  a  running  Emacs  instance.   How  this  is exactly handled
328              depends on the version of the used Pinentry.
329
330
331       --ignore-cache-for-signing
332              This option will let gpg-agent bypass the passphrase  cache  for
333              all  signing  operation.   Note that there is also a per-session
334              option to control this behavior but  this  command  line  option
335              takes precedence.
336
337
338       --default-cache-ttl n
339              Set  the  time a cache entry is valid to n seconds.  The default
340              is 600 seconds.  Each  time  a  cache  entry  is  accessed,  the
341              entry's timer is reset.  To set an entry's maximum lifetime, use
342              max-cache-ttl.  Note that a cached passphrase  may  not  evicted
343              immediately from memory if no client requests a cache operation.
344              This is due to an internal housekeeping function which  is  only
345              run every few seconds.
346
347
348       --default-cache-ttl-ssh n
349              Set  the time a cache entry used for SSH keys is valid to n sec‐
350              onds.  The default is 1800 seconds.  Each time a cache entry  is
351              accessed, the entry's timer is reset.  To set an entry's maximum
352              lifetime, use max-cache-ttl-ssh.
353
354
355       --max-cache-ttl n
356              Set the maximum time a cache entry is valid to n seconds.  After
357              this  time  a  cache  entry  will be expired even if it has been
358              accessed recently or has been set  using  gpg-preset-passphrase.
359              The default is 2 hours (7200 seconds).
360
361
362       --max-cache-ttl-ssh n
363              Set the maximum time a cache entry used for SSH keys is valid to
364              n seconds.  After this time a cache entry will be  expired  even
365              if  it has been accessed recently or has been set using gpg-pre‐
366              set-passphrase.  The default is 2 hours (7200 seconds).
367
368
369       --enforce-passphrase-constraints
370              Enforce the passphrase constraints by not allowing the  user  to
371              bypass them using the ``Take it anyway'' button.
372
373
374       --min-passphrase-len n
375              Set  the  minimal  length  of a passphrase.  When entering a new
376              passphrase shorter than this value a warning will be  displayed.
377              Defaults to 8.
378
379
380       --min-passphrase-nonalpha n
381              Set  the minimal number of digits or special characters required
382              in a passphrase.  When entering a new passphrase with less  than
383              this  number  of  digits or special characters a warning will be
384              displayed.  Defaults to 1.
385
386
387       --check-passphrase-pattern file
388              Check the passphrase against the pattern given  in  file.   When
389              entering  a new passphrase matching one of these pattern a warn‐
390              ing will be displayed. file should be an absolute filename.  The
391              default is not to use any pattern file.
392
393              Security  note: It is known that checking a passphrase against a
394              list of pattern or even against a  complete  dictionary  is  not
395              very  effective  to  enforce  good passphrases.  Users will soon
396              figure up ways to bypass such a policy.  A better policy  is  to
397              educate  users on good security behavior and optionally to run a
398              passphrase cracker regularly on all users passphrases  to  catch
399              the very simple ones.
400
401
402       --max-passphrase-days n
403              Ask  the  user  to  change  the passphrase if n days have passed
404              since the last  change.   With  --enforce-passphrase-constraints
405              set the user may not bypass this check.
406
407
408       --enable-passphrase-history
409              This option does nothing yet.
410
411
412       --pinentry-invisible-char char
413              This  option asks the Pinentry to use char for displaying hidden
414              characters.  char must be one character UTF-8 string.  A  Pinen‐
415              try may or may not honor this request.
416
417
418       --pinentry-timeout n
419              This option asks the Pinentry to timeout after n seconds with no
420              user input.  The default value of 0 does not ask the pinentry to
421              timeout,  however  a  Pinentry  may  use its own default timeout
422              value in this case.  A  Pinentry  may  or  may  not  honor  this
423              request.
424
425
426       --pinentry-program filename
427              Use program filename as the PIN entry.  The default is installa‐
428              tion dependent.  With the default configuration the name of  the
429              default  pinentry is ‘pinentry’; if that file does not exist but
430              a ‘pinentry-basic’ exist the latter is used.
431
432              On a Windows platform the default is to use the  first  existing
433              program       from      this      list:      ‘bin\pinentry.exe’,
434..\Gpg4win\bin\pinentry.exe’,        ‘..\Gpg4win\pinentry.exe’,
435..\GNU\GnuPG\pinentry.exe’,          ‘..\GNU\bin\pinentry.exe’,
436bin\pinentry-basic.exe’ where the file names  are  relative  to
437              the GnuPG installation directory.
438
439
440
441       --pinentry-touch-file filename
442              By default the filename of the socket gpg-agent is listening for
443              requests is passed to Pinentry, so that it can touch  that  file
444              before  exiting (it does this only in curses mode).  This option
445              changes the file passed to Pinentry to  filename.   The  special
446              name  /dev/null  may be used to completely disable this feature.
447              Note that Pinentry will not  create  that  file,  it  will  only
448              change the modification and access time.
449
450
451
452       --scdaemon-program filename
453              Use  program  filename  as the Smartcard daemon.  The default is
454              installation dependent and can be shown with  the  gpgconf  com‐
455              mand.
456
457
458       --disable-scdaemon
459              Do  not  make  use  of  the  scdaemon tool.  This option has the
460              effect of disabling the  ability  to  do  smartcard  operations.
461              Note,  that  enabling  this  option  at runtime does not kill an
462              already forked scdaemon.
463
464
465       --disable-check-own-socket
466              gpg-agent employs  a  periodic  self-test  to  detect  a  stolen
467              socket.   This  usually means a second instance of gpg-agent has
468              taken over the socket and gpg-agent will then terminate  itself.
469              This  option may be used to disable this self-test for debugging
470              purposes.
471
472
473       --use-standard-socket
474       --no-use-standard-socket
475       --use-standard-socket-p
476              Since GnuPG 2.1 the  standard  socket  is  always  used.   These
477              options  have no more effect.  The command gpg-agent --use-stan‐
478              dard-socket-p will thus always return success.
479
480
481       --display string
482       --ttyname string
483       --ttytype string
484       --lc-ctype string
485       --lc-messages string
486       --xauthority string
487              These options are used with the server mode to pass localization
488              information.
489
490
491       --keep-tty
492       --keep-display
493              Ignore  requests  to change the current tty or X window system's
494              DISPLAY variable respectively.   This  is  useful  to  lock  the
495              pinentry to pop up at the tty or display you started the agent.
496
497
498       --listen-backlog n
499              Set  the size of the queue for pending connections.  The default
500              is 64.
501
502
503
504       --extra-socket name
505              The extra socket is created by default, you may use this  option
506              to  change  the  name of the socket.  To disable the creation of
507              the socket use ``none'' or ``/dev/null'' for name.
508
509              Also listen on native gpg-agent connections on the given socket.
510              The intended use for this extra socket is to setup a Unix domain
511              socket forwarding from a remote machine to this  socket  on  the
512              local  machine.   A  gpg  running on the remote machine may then
513              connect to the local gpg-agent and use its private  keys.   This
514              enables  decrypting  or signing data on a remote machine without
515              exposing the private keys to the remote machine.
516
517
518
519       --enable-extended-key-format
520              This option creates keys in the  extended  private  key  format.
521              Changing  the  passphrase  of a key will also convert the key to
522              that new format.  Using  this  option  makes  the  private  keys
523              unreadable  for gpg-agent versions before 2.1.12.  The advantage
524              of the extended private key format is that it is text based  and
525              can  carry  additional  meta  data.   Note that this option also
526              changes the key protection format to use OCB mode.
527
528
529
530       --enable-ssh-support
531       --enable-putty-support
532
533              The OpenSSH Agent protocol is always enabled, but gpg-agent will
534              only set the SSH_AUTH_SOCK variable if this flag is given.
535
536              In this mode of operation, the agent does not only implement the
537              gpg-agent protocol, but also the agent protocol used by  OpenSSH
538              (through  a separate socket).  Consequently, it should be possi‐
539              ble to use the gpg-agent as a drop-in replacement for  the  well
540              known ssh-agent.
541
542              SSH  Keys,  which  are  to be used through the agent, need to be
543              added to the gpg-agent initially through  the  ssh-add  utility.
544              When  a  key  is added, ssh-add will ask for the password of the
545              provided key file and send the unprotected key material  to  the
546              agent;  this causes the gpg-agent to ask for a passphrase, which
547              is to be used for encrypting the newly received key and  storing
548              it in a gpg-agent specific directory.
549
550              Once  a  key  has been added to the gpg-agent this way, the gpg-
551              agent will be ready to use the key.
552
553              Note: in case the gpg-agent receives a  signature  request,  the
554              user might need to be prompted for a passphrase, which is neces‐
555              sary for decrypting the stored key.  Since the ssh-agent  proto‐
556              col  does not contain a mechanism for telling the agent on which
557              display/terminal it is running, gpg-agent's ssh-support will use
558              the  TTY  or  X  display  where  gpg-agent has been started.  To
559              switch this display to the current one,  the  following  command
560              may be used:
561
562         gpg-connect-agent updatestartuptty /bye
563
564       Although  all  GnuPG  components  try to start the gpg-agent as needed,
565       this is not possible for the ssh support  because  ssh  does  not  know
566       about it.  Thus if no GnuPG tool which accesses the agent has been run,
567       there is no guarantee that ssh is able to use gpg-agent for authentica‐
568       tion.   To fix this you may start gpg-agent if needed using this simple
569       command:
570
571         gpg-connect-agent /bye
572
573       Adding the --verbose shows the progress of starting the agent.
574
575       The --enable-putty-support is only available under Windows  and  allows
576       the  use of gpg-agent with the ssh implementation putty.  This is simi‐
577       lar to the regular ssh-agent support but makes use of  Windows  message
578       queue as required by putty.
579
580
581
582       --ssh-fingerprint-digest
583
584              Select  the  digest  algorithm  used to compute ssh fingerprints
585              that are communicated to the user,  e.g.  in  pinentry  dialogs.
586              OpenSSH  has  transitioned  from  using  MD5  to the more secure
587              SHA256.
588
589
590
591       --auto-expand-secmem n
592              Allow Libgcrypt to expand its secure memory  area  as  required.
593              The  optional value n is a non-negative integer with a suggested
594              size in bytes of each additionally allocated secure memory area.
595              The  value  is rounded up to the next 32 KiB; usual C style pre‐
596              fixes are allowed.  For an heavy loaded gpg-agent with many con‐
597              current connection this option avoids sign or decrypt errors due
598              to out of secure memory error returns.
599
600
601       --s2k-count n
602              Specify the iteration count  used  to  protect  the  passphrase.
603              This option can be used to override the auto-calibration done by
604              default.  The auto-calibration computes a count  which  requires
605              100ms to mangle a given passphrase.
606
607              To  view  the actually used iteration count and the milliseconds
608              required for an S2K operation use:
609
610         gpg-connect-agent 'GETINFO s2k_count' /bye
611         gpg-connect-agent 'GETINFO s2k_time' /bye
612
613       To view the auto-calibrated count use:
614
615         gpg-connect-agent 'GETINFO s2k_count_cal' /bye
616
617
618

EXAMPLES

620       It is important to set the environment variable GPG_TTY in  your  login
621       shell, for example in the ‘~/.bashrc’ init script:
622
623           export GPG_TTY=$(tty)
624
625       If  you  enabled the Ssh Agent Support, you also need to tell ssh about
626       it by adding this to your init script:
627
628         unset SSH_AGENT_PID
629         if [ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]; then
630           export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
631         fi
632
633
634
635

FILES

637       There are a few configuration files needed for  the  operation  of  the
638       agent.  By  default they may all be found in the current home directory
639       (see: [option --homedir]).
640
641
642
643       gpg-agent.conf
644                This is the standard configuration file read by gpg-agent on
645                startup.  It may contain any valid long option; the leading
646                two dashes may not be entered and the option may not be abbre‐
647              viated.
648                This file is also read after a SIGHUP however only a few
649                options  will  actually have an effect.  This default name may
650              be
651                changed on the command line (see: [option --options]).
652                You should backup this file.
653
654
655       trustlist.txt
656                This is the list of trusted  keys.   You  should  backup  this
657              file.
658
659                Comment  lines,  indicated  by a leading hash mark, as well as
660              empty
661                lines are ignored.  To mark a key as trusted you need to enter
662              its
663                fingerprint  followed  by  a  space  and  a  capital letter S.
664              Colons
665                may optionally be used to separate the bytes of a fingerprint;
666              this
667                enables cutting and pasting the fingerprint from a key listing
668              output.  If
669                the line is prefixed with a ! the key is explicitly marked as
670                not trusted.
671
672                Here is an example where two keys  are  marked  as  ultimately
673              trusted
674                and one as not trusted:
675
676                  .RS 2
677                # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
678                A6935DD34EF3087973C706FC311AA2CCF733765B S
679
680                # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
681                DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S
682
683                # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
684                !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
685                .fi
686
687       Before entering a key into this file, you need to ensure its
688       authenticity.  How to do this depends on your organisation; your
689       administrator might have already entered those keys which are deemed
690       trustworthy enough into this file.  Places where to look for the
691       fingerprint of a root certificate are letters received from the CA or
692       the website of the CA (after making 100% sure that this is indeed the
693       website of that CA).  You may want to consider disallowing interactive
694       updates of this file by using the [option --no-allow-mark-trusted].
695       It might even be advisable to change the permissions to read-only so
696       that this file can't be changed inadvertently.
697
698       As a special feature a line include-default will include a global
699       list of trusted certificates (e.g. ‘/etc/gnupg/trustlist.txt’).
700       This global list is also used if the local list is not available.
701
702       It is possible to add further flags after the S for use by the
703       caller:
704
705
706
707              relax  Relax checking of some root certificate requirements.  As of now this
708                     flag allows the use of root certificates with a missing basicConstraints
709                     attribute (despite that it is a MUST for CA certificates) and disables
710                     CRL checking for the root certificate.
711
712
713              cm     If validation of a certificate finally issued by a CA with this flag set
714                     fails, try again using the chain validation model.
715
716
717
718
719       sshcontrol
720              This file is used when support for the secure shell agent protocol has
721              been enabled (see: [option --enable-ssh-support]). Only keys present in
722              this file are used in the SSH protocol.  You should backup this file.
723
724              The ssh-add tool may be used to add new entries to this file;
725              you may also add them manually.  Comment lines, indicated by a leading
726              hash mark, as well as empty lines are ignored.  An entry starts with
727              optional whitespace, followed by the keygrip of the key given as 40 hex
728              digits, optionally followed by the caching TTL in seconds and another
729              optional field for arbitrary flags.  A non-zero TTL overrides the global
730              default as set by --default-cache-ttl-ssh.
731
732              The only flag support is confirm.  If this flag is found for a
733              key, each use of the key will pop up a pinentry to confirm the use of
734              that key.  The flag is automatically set if a new key was loaded into
735              gpg-agent using the option -c of the ssh-add
736              command.
737
738              The keygrip may be prefixed with a ! to disable an entry.
739
740              The following example lists exactly one key.  Note that keys available
741              through a OpenPGP smartcard in the active smartcard reader are
742              implicitly added to this list; i.e. there is no need to list them.
743
744                # Key added on: 2011-07-20 20:38:46
745                # Fingerprint:  5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
746                34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
747
748
749       private-keys-v1.d/
750
751                This is the directory where gpg-agent stores the private keys.
752              Each
753                key is stored in a file with the name made up of  the  keygrip
754              and the
755                suffix ‘key’.  You should backup all files in this directory
756                and take great care to keep this backup closed away.
757
758
759
760       Note that on larger installations, it is useful to put predefined files
761       into the directory ‘/etc/skel/.gnupg’ so that newly created users start
762       up with a working configuration.  For existing users the a small helper
763       script is provided to create these files (see: [addgnupghome]).
764
765
766
767
768

SIGNALS

770       A running gpg-agent may be controlled by signals, i.e. using  the  kill
771       command to send a signal to the process.
772
773       Here is a list of supported signals:
774
775
776
777       SIGHUP This  signal  flushes  all cached passphrases and if the program
778              has been started with a configuration  file,  the  configuration
779              file  is  read  again.  Only certain options are honored: quiet,
780              verbose, debug, debug-all, debug-level, debug-pinentry, no-grab,
781              pinentry-program,   pinentry-invisible-char,  default-cache-ttl,
782              max-cache-ttl,  ignore-cache-for-signing,  s2k-count,  no-allow-
783              external-cache,   allow-emacs-pinentry,   no-allow-mark-trusted,
784              disable-scdaemon, and  disable-check-own-socket.   scdaemon-pro‐
785              gram  is  also  supported but due to the current implementation,
786              which calls the scdaemon only once, it is not of much use unless
787              you manually kill the scdaemon.
788
789
790
791       SIGTERM
792              Shuts  down the process but waits until all current requests are
793              fulfilled.  If the process has received 3 of these  signals  and
794              requests are still pending, a shutdown is forced.
795
796
797       SIGINT Shuts down the process immediately.
798
799
800       SIGUSR1
801              Dump internal information to the log file.
802
803
804       SIGUSR2
805              This signal is used for internal purposes.
806
807

SEE ALSO

809       gpg(1), gpgsm(1), gpgconf(1), gpg-connect-agent(1), scdaemon(1)
810
811       The full documentation for this tool is maintained as a Texinfo manual.
812       If GnuPG and the info program are properly installed at your site,  the
813       command
814
815         info gnupg
816
817       should  give  you access to the complete manual including a menu struc‐
818       ture and an index.
819
820
821
822GnuPG 2.2.9                       2018-06-12                      GPG-AGENT(1)
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