1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
|
@c Copyright (C) 2002 Free Software Foundation, Inc.
@c This is part of the GnuPG manual.
@c For copying conditions, see the file gnupg.texi.
@include defs.inc
@node Invoking GPG-AGENT
@chapter Invoking GPG-AGENT
@cindex GPG-AGENT command options
@cindex command options
@cindex options, GPG-AGENT command
@manpage gpg-agent.1
@ifset manverb
.B gpg-agent
\- Secret key management for GnuPG
@end ifset
@mansect synopsis
@ifset manverb
.B gpg-agent
.RB [ \-\-homedir
.IR dir ]
.RB [ \-\-options
.IR file ]
.RI [ options ]
.br
.B gpg-agent
.RB [ \-\-homedir
.IR dir ]
.RB [ \-\-options
.IR file ]
.RI [ options ]
.B \-\-server
.br
.B gpg-agent
.RB [ \-\-homedir
.IR dir ]
.RB [ \-\-options
.IR file ]
.RI [ options ]
.B \-\-daemon
.RI [ command_line ]
@end ifset
@mansect description
@command{gpg-agent} is a daemon to manage secret (private) keys
independently from any protocol. It is used as a backend for
@command{gpg} and @command{gpgsm} as well as for a couple of other
utilities.
The agent is automatically started on demand by @command{gpg},
@command{gpgsm}, @command{gpgconf}, or @command{gpg-connect-agent}.
Thus there is no reason to start it manually. In case you want to use
the included Secure Shell Agent you may start the agent using:
@c From dkg on gnupg-devel on 2016-04-21:
@c
@c Here's an attempt at writing a short description of the goals of an
@c isolated cryptographic agent:
@c
@c A cryptographic agent should control access to secret key material.
@c The agent permits use of the secret key material by a supplicant
@c without providing a copy of the secret key material to the supplicant.
@c
@c An isolated cryptographic agent separates the request for use of
@c secret key material from permission for use of secret key material.
@c That is, the system or process requesting use of the key (the
@c "supplicant") can be denied use of the key by the owner/operator of
@c the agent (the "owner"), which the supplicant has no control over.
@c
@c One way of enforcing this split is a per-key or per-session
@c passphrase, known only by the owner, which must be supplied to the
@c agent to permit the use of the secret key material. Another way is
@c with an out-of-band permission mechanism (e.g. a button or GUI
@c interface that the owner has access to, but the supplicant does not).
@c
@c The rationale for this separation is that it allows access to the
@c secret key to be tightly controlled and audited, and it doesn't permit
@c the supplicant to either copy the key or to override the owner's
@c intentions.
@example
gpg-connect-agent /bye
@end example
@noindent
If you want to manually terminate the currently-running agent, you can
safely do so with:
@example
gpgconf --kill gpg-agent
@end example
@noindent
@efindex GPG_TTY
You should always add the following lines to your @code{.bashrc} or
whatever initialization file is used for all shell invocations:
@smallexample
GPG_TTY=$(tty)
export GPG_TTY
@end smallexample
@noindent
It is important that this environment variable always reflects the
output of the @code{tty} command. For W32 systems this option is not
required.
Please make sure that a proper pinentry program has been installed
under the default filename (which is system dependent) or use the
option @option{pinentry-program} to specify the full name of that program.
It is often useful to install a symbolic link from the actual used
pinentry (e.g. @file{@value{BINDIR}/pinentry-gtk}) to the expected
one (e.g. @file{@value{BINDIR}/pinentry}).
@manpause
@noindent
@xref{Option Index}, for an index to @command{GPG-AGENT}'s commands and options.
@mancont
@menu
* Agent Commands:: List of all commands.
* Agent Options:: List of all options.
* Agent Configuration:: Configuration files.
* Agent Signals:: Use of some signals.
* Agent Examples:: Some usage examples.
* Agent Protocol:: The protocol the agent uses.
@end menu
@mansect commands
@node Agent Commands
@section Commands
Commands are not distinguished from options except for the fact that
only one command is allowed.
@table @gnupgtabopt
@item --version
@opindex version
Print the program version and licensing information. Note that you cannot
abbreviate this command.
@item --help
@itemx -h
@opindex help
Print a usage message summarizing the most useful command-line options.
Note that you cannot abbreviate this command.
@item --dump-options
@opindex dump-options
Print a list of all available options and commands. Note that you cannot
abbreviate this command.
@item --server
@opindex server
Run in server mode and wait for commands on the @code{stdin}. The
default mode is to create a socket and listen for commands there.
@item --daemon [@var{command line}]
@opindex daemon
Start the gpg-agent as a daemon; that is, detach it from the console
and run it in the background.
As an alternative you may create a new process as a child of
gpg-agent: @code{gpg-agent --daemon /bin/sh}. This way you get a new
shell with the environment setup properly; after you exit from this
shell, gpg-agent terminates within a few seconds.
@item --supervised
@opindex supervised
Run in the foreground, sending logs by default to stderr, and
listening on provided file descriptors, which must already be bound to
listening sockets. This option is deprecated and not supported on
Windows.
If in @file{common.conf} the option @option{no-autostart} is set, any
start attempts will be ignored.
In --supervised mode, different file descriptors can be provided for
use as different socket types (e.g. ssh, extra) as long as they are
identified in the environment variable @code{LISTEN_FDNAMES} (see
sd_listen_fds(3) on some Linux distributions for more information on
this convention).
@end table
@mansect options
@node Agent Options
@section Option Summary
Options may either be used on the command line or, after stripping off
the two leading dashes, in the configuration file.
@table @gnupgtabopt
@anchor{option --options}
@item --options @var{file}
@opindex options
Reads configuration from @var{file} instead of from the default
per-user configuration file. The default configuration file is named
@file{gpg-agent.conf} and expected in the @file{.gnupg} directory
directly below the home directory of the user. This option is ignored
if used in an options file.
@anchor{option --homedir}
@include opt-homedir.texi
@item -v
@itemx --verbose
@opindex verbose
Outputs additional information while running.
You can increase the verbosity by giving several
verbose commands to @command{gpg-agent}, such as @samp{-vv}.
@item -q
@itemx --quiet
@opindex quiet
Try to be as quiet as possible.
@item --batch
@opindex batch
Don't invoke a pinentry or do any other thing requiring human interaction.
@item --faked-system-time @var{epoch}
@opindex faked-system-time
This option is only useful for testing; it sets the system time back or
forth to @var{epoch} which is the number of seconds elapsed since the year
1970.
@item --debug-level @var{level}
@opindex debug-level
Select the debug level for investigating problems. @var{level} may be
a numeric value or a keyword:
@table @code
@item none
No debugging at all. A value of less than 1 may be used instead of
the keyword.
@item basic
Some basic debug messages. A value between 1 and 2 may be used
instead of the keyword.
@item advanced
More verbose debug messages. A value between 3 and 5 may be used
instead of the keyword.
@item expert
Even more detailed messages. A value between 6 and 8 may be used
instead of the keyword.
@item guru
All of the debug messages you can get. A value greater than 8 may be
used instead of the keyword. The creation of hash tracing files is
only enabled if the keyword is used.
@end table
How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They are
however carefully selected to best aid in debugging.
@item --debug @var{flags}
@opindex debug
Set debug flags. All flags are or-ed and @var{flags} may be given
in C syntax (e.g. 0x0042) or as a comma separated list of flag names.
To get a list of all supported flags the single word "help" can be
used. This option is only useful for debugging and the behavior may
change at any time without notice.
@item --debug-all
@opindex debug-all
Same as @code{--debug=0xffffffff}
@item --debug-wait @var{n}
@opindex debug-wait
When running in server mode, wait @var{n} seconds before entering the
actual processing loop and print the pid. This gives time to attach a
debugger.
@item --debug-quick-random
@opindex debug-quick-random
This option inhibits the use of the very secure random quality level
(Libgcrypt’s @code{GCRY_VERY_STRONG_RANDOM}) and degrades all request
down to standard random quality. It is only used for testing and
should not be used for any production quality keys. This option is
only effective when given on the command line.
On GNU/Linux, another way to quickly generate insecure keys is to use
@command{rngd} to fill the kernel's entropy pool with lower quality
random data. @command{rngd} is typically provided by the
@command{rng-tools} package. It can be run as follows: @samp{sudo
rngd -f -r /dev/urandom}.
@item --debug-pinentry
@opindex debug-pinentry
This option enables extra debug information pertaining to the
Pinentry. As of now it is only useful when used along with
@code{--debug 1024}.
@item --no-detach
@opindex no-detach
Don't detach the process from the console. This is mainly useful for
debugging.
@item --steal-socket
@opindex steal-socket
In @option{--daemon} mode, gpg-agent detects an already running
gpg-agent and does not allow to start a new instance. This option can
be used to override this check: the new gpg-agent process will try to
take over the communication sockets from the already running process
and start anyway. This option should in general not be used.
@item -s
@itemx --sh
@itemx -c
@itemx --csh
@opindex sh
@opindex csh
@efindex SHELL
Format the info output in daemon mode for use with the standard Bourne
shell or the C-shell respectively. The default is to guess it based on
the environment variable @code{SHELL} which is correct in almost all
cases.
@item --grab
@itemx --no-grab
@opindex grab
@opindex no-grab
Tell the pinentry to grab the keyboard and mouse. This option should
be used on X-Servers to avoid X-sniffing attacks. Any use of the
option @option{--grab} overrides an used option @option{--no-grab}.
The default is @option{--no-grab}.
@anchor{option --log-file}
@item --log-file @var{file}
@opindex log-file
@efindex HKCU\Software\GNU\GnuPG:DefaultLogFile
Append all logging output to @var{file}. This is very helpful in
seeing what the agent actually does. Use @file{socket://} to log to
socket. If neither a log file nor a log file descriptor has been set
on a Windows platform, the Registry entry
@code{HKCU\Software\GNU\GnuPG:DefaultLogFile}, if set, is used to
specify the logging output.
@anchor{option --no-allow-mark-trusted}
@item --no-allow-mark-trusted
@opindex no-allow-mark-trusted
Do not allow clients to mark keys as trusted, i.e. put them into the
@file{trustlist.txt} file. This makes it harder for users to inadvertently
accept Root-CA keys.
@anchor{option --no-user-trustlist}
@item --no-user-trustlist
@opindex no-user-trustlist
Entirely ignore the user trust list and consider only the global
trustlist (@file{@value{SYSCONFDIR}/trustlist.txt}). This
implies the @ref{option --no-allow-mark-trusted}.
@item --sys-trustlist-name @var{file}
@opindex sys-trustlist-name
Changes the default name for the global trustlist from "trustlist.txt"
to @var{file}. If @var{file} does not contain any slashes and does
not start with "~/" it is searched in the system configuration
directory (@file{@value{SYSCONFDIR}}).
@anchor{option --allow-preset-passphrase}
@item --allow-preset-passphrase
@opindex allow-preset-passphrase
This option allows the use of @command{gpg-preset-passphrase} to seed the
internal cache of @command{gpg-agent} with passphrases.
@anchor{option --no-allow-loopback-pinentry}
@item --no-allow-loopback-pinentry
@item --allow-loopback-pinentry
@opindex no-allow-loopback-pinentry
@opindex allow-loopback-pinentry
Disallow or allow clients to use the loopback pinentry features; see
the option @option{pinentry-mode} for details. Allow is the default.
The @option{--force} option of the Assuan command @command{DELETE_KEY}
is also controlled by this option: The option is ignored if a loopback
pinentry is disallowed.
@item --no-allow-external-cache
@opindex no-allow-external-cache
Tell Pinentry not to enable features which use an external cache for
passphrases.
Some desktop environments prefer to unlock all
credentials with one master password and may have installed a Pinentry
which employs an additional external cache to implement such a policy.
By using this option the Pinentry is advised not to make use of such a
cache and instead always ask the user for the requested passphrase.
@item --allow-emacs-pinentry
@opindex allow-emacs-pinentry
Tell Pinentry to allow features to divert the passphrase entry to a
running Emacs instance. How this is exactly handled depends on the
version of the used Pinentry.
@item --ignore-cache-for-signing
@opindex ignore-cache-for-signing
This option will let @command{gpg-agent} bypass the passphrase cache for all
signing operation. Note that there is also a per-session option to
control this behavior but this command line option takes precedence.
@item --default-cache-ttl @var{n}
@opindex default-cache-ttl
Set the time a cache entry is valid to @var{n} seconds. The default
is 600 seconds. Each time a cache entry is accessed, the entry's
timer is reset. To set an entry's maximum lifetime, use
@command{max-cache-ttl}. Note that a cached passphrase may not be
evicted immediately from memory if no client requests a cache
operation. This is due to an internal housekeeping function which is
only run every few seconds.
@item --default-cache-ttl-ssh @var{n}
@opindex default-cache-ttl
Set the time a cache entry used for SSH keys is valid to @var{n}
seconds. The default is 1800 seconds. Each time a cache entry is
accessed, the entry's timer is reset. To set an entry's maximum
lifetime, use @command{max-cache-ttl-ssh}.
@item --max-cache-ttl @var{n}
@opindex max-cache-ttl
Set the maximum time a cache entry is valid to @var{n} seconds. After
this time a cache entry will be expired even if it has been accessed
recently or has been set using @command{gpg-preset-passphrase}. The
default is 2 hours (7200 seconds).
@item --max-cache-ttl-ssh @var{n}
@opindex max-cache-ttl-ssh
Set the maximum time a cache entry used for SSH keys is valid to
@var{n} seconds. After this time a cache entry will be expired even
if it has been accessed recently or has been set using
@command{gpg-preset-passphrase}. The default is 2 hours (7200
seconds).
@item --enforce-passphrase-constraints
@opindex enforce-passphrase-constraints
Enforce the passphrase constraints by not allowing the user to bypass
them using the ``Take it anyway'' button.
@item --min-passphrase-len @var{n}
@opindex min-passphrase-len
Set the minimal length of a passphrase. When entering a new passphrase
shorter than this value a warning will be displayed. Defaults to 8.
@item --min-passphrase-nonalpha @var{n}
@opindex min-passphrase-nonalpha
Set the minimal number of digits or special characters required in a
passphrase. When entering a new passphrase with less than this number
of digits or special characters a warning will be displayed. Defaults
to 1.
@item --check-passphrase-pattern @var{file}
@itemx --check-sym-passphrase-pattern @var{file}
@opindex check-passphrase-pattern
@opindex check-sym-passphrase-pattern
Check the passphrase against the pattern given in @var{file}. When
entering a new passphrase matching one of these pattern a warning will
be displayed. If @var{file} does not contain any slashes and does not
start with "~/" it is searched in the system configuration directory
(@file{@value{SYSCONFDIR}}). The default is not to use any
pattern file. The second version of this option is only used when
creating a new symmetric key to allow the use of different patterns
for such passphrases.
Security note: It is known that checking a passphrase against a list of
pattern or even against a complete dictionary is not very effective to
enforce good passphrases. Users will soon figure up ways to bypass such
a policy. A better policy is to educate users on good security
behavior and optionally to run a passphrase cracker regularly on all
users passphrases to catch the very simple ones.
@item --max-passphrase-days @var{n}
@opindex max-passphrase-days
Ask the user to change the passphrase if @var{n} days have passed since
the last change. With @option{--enforce-passphrase-constraints} set the
user may not bypass this check.
@item --enable-passphrase-history
@opindex enable-passphrase-history
This option does nothing yet.
@item --pinentry-invisible-char @var{char}
@opindex pinentry-invisible-char
This option asks the Pinentry to use @var{char} for displaying hidden
characters. @var{char} must be one character UTF-8 string. A
Pinentry may or may not honor this request.
@item --pinentry-timeout @var{n}
@opindex pinentry-timeout
This option asks the Pinentry to timeout after @var{n} seconds with no
user input. The default value of 0 does not ask the pinentry to
timeout, however a Pinentry may use its own default timeout value in
this case. A Pinentry may or may not honor this request.
@item --pinentry-formatted-passphrase
@opindex pinentry-formatted-passphrase
This option asks the Pinentry to enable passphrase formatting when asking the
user for a new passphrase and masking of the passphrase is turned off.
If passphrase formatting is enabled, then all non-breaking space characters
are stripped from the entered passphrase. Passphrase formatting is mostly
useful in combination with passphrases generated with the GENPIN
feature of some Pinentries. Note that such a generated
passphrase, if not modified by the user, skips all passphrase
constraints checking because such constraints would actually weaken
the generated passphrase.
@item --pinentry-program @var{filename}
@opindex pinentry-program
Use program @var{filename} as the PIN entry. The default is
installation dependent. With the default configuration the name of
the default pinentry is @file{pinentry}; if that file does not exist
but a @file{pinentry-basic} exist the latter is used.
On a Windows platform the default is to use the first existing program
from this list:
@file{bin\pinentry.exe},
@file{..\Gpg4win\bin\pinentry.exe},
@file{..\Gpg4win\pinentry.exe},
@file{..\GNU\GnuPG\pinentry.exe},
@file{..\GNU\bin\pinentry.exe},
@file{bin\pinentry-basic.exe}
where the file names are relative to the GnuPG installation directory.
@item --pinentry-touch-file @var{filename}
@opindex pinentry-touch-file
By default the filename of the socket gpg-agent is listening for
requests is passed to Pinentry, so that it can touch that file before
exiting (it does this only in curses mode). This option changes the
file passed to Pinentry to @var{filename}. The special name
@code{/dev/null} may be used to completely disable this feature. Note
that Pinentry will not create that file, it will only change the
modification and access time.
@item --scdaemon-program @var{filename}
@opindex scdaemon-program
Use program @var{filename} as the Smartcard daemon. The default is
installation dependent and can be shown with the @command{gpgconf}
command.
@item --disable-scdaemon
@opindex disable-scdaemon
Do not make use of the scdaemon tool. This option has the effect of
disabling the ability to do smartcard operations. Note, that enabling
this option at runtime does not kill an already forked scdaemon.
@item --disable-check-own-socket
@opindex disable-check-own-socket
@command{gpg-agent} employs a periodic self-test to detect a stolen
socket. This usually means a second instance of @command{gpg-agent}
has taken over the socket and @command{gpg-agent} will then terminate
itself. This option may be used to disable this self-test for
debugging purposes.
@item --use-standard-socket
@itemx --no-use-standard-socket
@itemx --use-standard-socket-p
@opindex use-standard-socket
@opindex no-use-standard-socket
@opindex use-standard-socket-p
Since GnuPG 2.1 the standard socket is always used. These options
have no more effect. The command @code{gpg-agent
--use-standard-socket-p} will thus always return success.
@item --display @var{string}
@itemx --ttyname @var{string}
@itemx --ttytype @var{string}
@itemx --lc-ctype @var{string}
@itemx --lc-messages @var{string}
@itemx --xauthority @var{string}
@opindex display
@opindex ttyname
@opindex ttytype
@opindex lc-ctype
@opindex lc-messages
@opindex xauthority
These options are used with the server mode to pass localization
information.
@item --keep-tty
@itemx --keep-display
@opindex keep-tty
@opindex keep-display
Ignore requests to change the current @code{tty} or X window system's
@code{DISPLAY} variable respectively. This is useful to lock the
pinentry to pop up at the @code{tty} or display you started the agent.
@item --listen-backlog @var{n}
@opindex listen-backlog
Set the size of the queue for pending connections. The default is 64.
@anchor{option --extra-socket}
@item --extra-socket @var{name}
@opindex extra-socket
The extra socket is created by default, you may use this option to
change the name of the socket. To disable the creation of the socket
use ``none'' or ``/dev/null'' for @var{name}.
Also listen on native gpg-agent connections on the given socket. The
intended use for this extra socket is to setup a Unix domain socket
forwarding from a remote machine to this socket on the local machine.
A @command{gpg} running on the remote machine may then connect to the
local gpg-agent and use its private keys. This enables decrypting or
signing data on a remote machine without exposing the private keys to the
remote machine.
@item --enable-extended-key-format
@itemx --disable-extended-key-format
@opindex enable-extended-key-format
@opindex disable-extended-key-format
These options are obsolete and have no effect. The extended key format
is used for years now and has been supported since 2.1.12. Existing
keys in the old format are migrated to the new format as soon as they
are touched.
@anchor{option --enable-ssh-support}
@item --enable-ssh-support
@itemx --enable-putty-support
@opindex enable-ssh-support
@opindex enable-putty-support
The OpenSSH Agent protocol is always enabled, but @command{gpg-agent}
will only set the @code{SSH_AUTH_SOCK} variable if this flag is given.
In this mode of operation, the agent does not only implement the
gpg-agent protocol, but also the agent protocol used by OpenSSH
(through a separate socket). Consequently, it should be possible to use
the gpg-agent as a drop-in replacement for the well known ssh-agent.
SSH Keys, which are to be used through the agent, need to be added to
the gpg-agent initially through the ssh-add utility. When a key is
added, ssh-add will ask for the password of the provided key file and
send the unprotected key material to the agent; this causes the
gpg-agent to ask for a passphrase, which is to be used for encrypting
the newly received key and storing it in a gpg-agent specific
directory.
Once a key has been added to the gpg-agent this way, the gpg-agent
will be ready to use the key.
Note: in case the gpg-agent receives a signature request, the user might
need to be prompted for a passphrase, which is necessary for decrypting
the stored key. Since the ssh-agent protocol does not contain a
mechanism for telling the agent on which display/terminal it is running,
gpg-agent's ssh-support will use the TTY or X display where gpg-agent
has been started. To switch this display to the current one, the
following command may be used:
@smallexample
gpg-connect-agent updatestartuptty /bye
@end smallexample
Although all GnuPG components try to start the gpg-agent as needed, this
is not possible for the ssh support because ssh does not know about it.
Thus if no GnuPG tool which accesses the agent has been run, there is no
guarantee that ssh is able to use gpg-agent for authentication. To fix
this you may start gpg-agent if needed using this simple command:
@smallexample
gpg-connect-agent /bye
@end smallexample
Adding the @option{--verbose} shows the progress of starting the agent.
The @option{--enable-putty-support} is only available under Windows
and allows the use of gpg-agent with the ssh implementation
@command{putty}. This is similar to the regular ssh-agent support but
makes use of Windows message queue as required by @command{putty}.
@anchor{option --ssh-fingerprint-digest}
@item --ssh-fingerprint-digest
@opindex ssh-fingerprint-digest
Select the digest algorithm used to compute ssh fingerprints that are
communicated to the user, e.g. in pinentry dialogs. OpenSSH has
transitioned from using MD5 to the more secure SHA256.
@item --auto-expand-secmem @var{n}
@opindex auto-expand-secmem
Allow Libgcrypt to expand its secure memory area as required. The
optional value @var{n} is a non-negative integer with a suggested size
in bytes of each additionally allocated secure memory area. The value
is rounded up to the next 32 KiB; usual C style prefixes are allowed.
For an heavy loaded gpg-agent with many concurrent connection this
option avoids sign or decrypt errors due to out of secure memory error
returns.
@item --s2k-calibration @var{milliseconds}
@opindex s2k-calibration
Change the default calibration time to @var{milliseconds}. The given
value is capped at 60 seconds; a value of 0 resets to the compiled-in
default. This option is re-read on a SIGHUP (or @code{gpgconf
--reload gpg-agent}) and the S2K count is then re-calibrated.
@item --s2k-count @var{n}
@opindex s2k-count
Specify the iteration count used to protect the passphrase. This
option can be used to override the auto-calibration done by default.
The auto-calibration computes a count which requires by default 100ms
to mangle a given passphrase. See also @option{--s2k-calibration}.
To view the actually used iteration count and the milliseconds
required for an S2K operation use:
@example
gpg-connect-agent 'GETINFO s2k_count' /bye
gpg-connect-agent 'GETINFO s2k_time' /bye
@end example
To view the auto-calibrated count use:
@example
gpg-connect-agent 'GETINFO s2k_count_cal' /bye
@end example
@end table
@mansect files
@node Agent Configuration
@section Configuration
There are a few configuration files needed for the operation of the
agent. By default they may all be found in the current home directory
(@pxref{option --homedir}).
@table @file
@item gpg-agent.conf
@efindex gpg-agent.conf
This is the standard configuration file read by @command{gpg-agent} on
startup. It may contain any valid long option; the leading
two dashes may not be entered and the option may not be abbreviated.
This file is also read after a @code{SIGHUP} however only a few
options will actually have an effect. This default name may be
changed on the command line (@pxref{option --options}).
You should backup this file.
@item trustlist.txt
@efindex trustlist.txt
This is the list of trusted keys. You should backup this file.
Comment lines, indicated by a leading hash mark, as well as empty
lines are ignored. To mark a key as trusted you need to enter its
fingerprint followed by a space and a capital letter @code{S}. Colons
may optionally be used to separate the bytes of a fingerprint; this
enables cutting and pasting the fingerprint from a key listing output. If
the line is prefixed with a @code{!} the key is explicitly marked as
not trusted.
Here is an example where two keys are marked as ultimately trusted
and one as not trusted:
@cartouche
@smallexample
# CN=Wurzel ZS 3,O=Intevation GmbH,C=DE
A6935DD34EF3087973C706FC311AA2CCF733765B S
# CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE
DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S
# CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE
!14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S
@end smallexample
@end cartouche
Before entering a key into this file, you need to ensure its
authenticity. How to do this depends on your organisation; your
administrator might have already entered those keys which are deemed
trustworthy enough into this file. Places where to look for the
fingerprint of a root certificate are letters received from the CA or
the website of the CA (after making 100% sure that this is indeed the
website of that CA). You may want to consider disallowing interactive
updates of this file by using the @ref{option --no-allow-mark-trusted}.
It might even be advisable to change the permissions to read-only so
that this file can't be changed inadvertently.
As a special feature a line @code{include-default} will include a global
list of trusted certificates (e.g. @file{@value{SYSCONFDIR}/trustlist.txt}).
This global list is also used if the local list is not available;
the @ref{option --no-user-trustlist} enforces the use of only
this global list.
It is possible to add further flags after the @code{S} for use by the
caller:
@table @code
@item relax
@cindex relax
Relax checking of some root certificate requirements. As of now this
flag allows the use of root certificates with a missing basicConstraints
attribute (despite that it is a MUST for CA certificates) and disables
CRL checking for the root certificate.
@item cm
If validation of a certificate finally issued by a CA with this flag set
fails, try again using the chain validation model.
@item qual
The CA is allowed to issue certificates for qualified signatures.
This flag has an effect only if used in the global list. This is now
the preferred way to mark such CA; the old way of having a separate
file @file{qualified.txt} is still supported.
@item de-vs
The CA is part of an approved PKI for the German classification level
VS-NfD. It is only valid in the global trustlist. As of now this is
used only for documentation purpose.
@end table
@item sshcontrol
@efindex sshcontrol
This file is used when support for the secure shell agent protocol has
been enabled (@pxref{option --enable-ssh-support}). Only keys present in
this file are used in the SSH protocol. You should backup this file.
The @command{ssh-add} tool may be used to add new entries to this file;
you may also add them manually. Comment lines, indicated by a leading
hash mark, as well as empty lines are ignored. An entry starts with
optional whitespace, followed by the keygrip of the key given as 40 hex
digits, optionally followed by the caching TTL in seconds and another
optional field for arbitrary flags. A non-zero TTL overrides the global
default as set by @option{--default-cache-ttl-ssh}.
The only flag support is @code{confirm}. If this flag is found for a
key, each use of the key will pop up a pinentry to confirm the use of
that key. The flag is automatically set if a new key was loaded into
@code{gpg-agent} using the option @option{-c} of the @code{ssh-add}
command.
The keygrip may be prefixed with a @code{!} to disable an entry.
The following example lists exactly one key. Note that keys available
through a OpenPGP smartcard in the active smartcard reader are
implicitly added to this list; i.e. there is no need to list them.
@cartouche
@smallexample
# Key added on: 2011-07-20 20:38:46
# Fingerprint: 5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81
34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm
@end smallexample
@end cartouche
@item private-keys-v1.d/
@efindex private-keys-v1.d
This is the directory where gpg-agent stores the private keys. Each
key is stored in a file with the name made up of the keygrip and the
suffix @file{key}. You should backup all files in this directory
and take great care to keep this backup closed away.
@end table
Note that on larger installations, it is useful to put predefined
files into the directory @file{@value{SYSCONFSKELDIR}} so that newly created
users start up with a working configuration. For existing users the
a small helper script is provided to create these files (@pxref{addgnupghome}).
@c
@c Agent Signals
@c
@mansect signals
@node Agent Signals
@section Use of some signals
A running @command{gpg-agent} may be controlled by signals, i.e. using
the @command{kill} command to send a signal to the process.
Here is a list of supported signals:
@table @gnupgtabopt
@item SIGHUP
@cpindex SIGHUP
This signal flushes all cached passphrases and if the program has been
started with a configuration file, the configuration file is read
again. Only certain options are honored: @code{quiet},
@code{verbose}, @code{debug}, @code{debug-all}, @code{debug-level},
@code{debug-pinentry},
@code{no-grab},
@code{pinentry-program},
@code{pinentry-invisible-char},
@code{default-cache-ttl},
@code{max-cache-ttl}, @code{ignore-cache-for-signing},
@code{s2k-count},
@code{no-allow-external-cache}, @code{allow-emacs-pinentry},
@code{no-allow-mark-trusted}, @code{disable-scdaemon}, and
@code{disable-check-own-socket}. @code{scdaemon-program} is also
supported but due to the current implementation, which calls the
scdaemon only once, it is not of much use unless you manually kill the
scdaemon.
@item SIGTERM
@cpindex SIGTERM
Shuts down the process but waits until all current requests are
fulfilled. If the process has received 3 of these signals and requests
are still pending, a shutdown is forced.
@item SIGINT
@cpindex SIGINT
Shuts down the process immediately.
@item SIGUSR1
@cpindex SIGUSR1
Dump internal information to the log file.
@item SIGUSR2
@cpindex SIGUSR2
This signal is used for internal purposes.
@end table
@c
@c Examples
@c
@mansect examples
@node Agent Examples
@section Examples
It is important to set the environment variable @code{GPG_TTY} in
your login shell, for example in the @file{~/.bashrc} init script:
@cartouche
@example
export GPG_TTY=$(tty)
@end example
@end cartouche
If you enabled the Ssh Agent Support, you also need to tell ssh about
it by adding this to your init script:
@cartouche
@example
unset SSH_AGENT_PID
if [ "$@{gnupg_SSH_AUTH_SOCK_by:-0@}" -ne $$ ]; then
export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
fi
@end example
@end cartouche
@c
@c Assuan Protocol
@c
@manpause
@node Agent Protocol
@section Agent's Assuan Protocol
Note: this section does only document the protocol, which is used by
GnuPG components; it does not deal with the ssh-agent protocol. To
see the full specification of each command, use
@example
gpg-connect-agent 'help COMMAND' /bye
@end example
@noindent
or just 'help' to list all available commands.
@noindent
The @command{gpg-agent} daemon is started on demand by the GnuPG
components.
To identify a key we use a thing called keygrip which is the SHA-1 hash
of an canonical encoded S-Expression of the public key as used in
Libgcrypt. For the purpose of this interface the keygrip is given as a
hex string. The advantage of using this and not the hash of a
certificate is that it will be possible to use the same keypair for
different protocols, thereby saving space on the token used to keep the
secret keys.
The @command{gpg-agent} may send status messages during a command or when
returning from a command to inform a client about the progress or result of an
operation. For example, the @var{INQUIRE_MAXLEN} status message may be sent
during a server inquire to inform the client of the maximum usable length of
the inquired data (which should not be exceeded).
@menu
* Agent PKDECRYPT:: Decrypting a session key
* Agent PKSIGN:: Signing a Hash
* Agent GENKEY:: Generating a Key
* Agent IMPORT:: Importing a Secret Key
* Agent EXPORT:: Exporting a Secret Key
* Agent ISTRUSTED:: Importing a Root Certificate
* Agent GET_PASSPHRASE:: Ask for a passphrase
* Agent CLEAR_PASSPHRASE:: Expire a cached passphrase
* Agent PRESET_PASSPHRASE:: Set a passphrase for a keygrip
* Agent GET_CONFIRMATION:: Ask for confirmation
* Agent HAVEKEY:: Check whether a key is available
* Agent LEARN:: Register a smartcard
* Agent PASSWD:: Change a Passphrase
* Agent UPDATESTARTUPTTY:: Change the Standard Display
* Agent GETEVENTCOUNTER:: Get the Event Counters
* Agent GETINFO:: Return information about the process
* Agent OPTION:: Set options for the session
@end menu
@node Agent PKDECRYPT
@subsection Decrypting a session key
The client asks the server to decrypt a session key. The encrypted
session key should have all information needed to select the
appropriate secret key or to delegate it to a smartcard.
@example
SETKEY <keyGrip>
@end example
Tell the server about the key to be used for decryption. If this is
not used, @command{gpg-agent} may try to figure out the key by trying to
decrypt the message with each key available.
@example
PKDECRYPT
@end example
The agent checks whether this command is allowed and then does an
INQUIRY to get the ciphertext the client should then send the cipher
text.
@example
S: INQUIRE CIPHERTEXT
C: D (xxxxxx
C: D xxxx)
C: END
@end example
Please note that the server may send status info lines while reading the
data lines from the client. The data send is a SPKI like S-Exp with
this structure:
@example
(enc-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)))
@end example
Where algo is a string with the name of the algorithm; see the libgcrypt
documentation for a list of valid algorithms. The number and names of
the parameters depend on the algorithm. The agent does return an error
if there is an inconsistency.
If the decryption was successful the decrypted data is returned by
means of "D" lines.
Here is an example session:
@cartouche
@smallexample
C: PKDECRYPT
S: INQUIRE CIPHERTEXT
C: D (enc-val elg (a 349324324)
C: D (b 3F444677CA)))
C: END
S: # session key follows
S: S PADDING 0
S: D (value 1234567890ABCDEF0)
S: OK decryption successful
@end smallexample
@end cartouche
The “PADDING” status line is only send if gpg-agent can tell what kind
of padding is used. As of now only the value 0 is used to indicate
that the padding has been removed.
@node Agent PKSIGN
@subsection Signing a Hash
The client asks the agent to sign a given hash value. A default key
will be chosen if no key has been set. To set a key a client first
uses:
@example
SIGKEY <keyGrip>
@end example
This can be used multiple times to create multiple signature, the list
of keys is reset with the next PKSIGN command or a RESET. The server
tests whether the key is a valid key to sign something and responds with
okay.
@example
SETHASH --hash=<name>|<algo> <hexstring>
@end example
The client can use this command to tell the server about the data <hexstring>
(which usually is a hash) to be signed. <algo> is the decimal encoded hash
algorithm number as used by Libgcrypt. Either <algo> or --hash=<name>
must be given. Valid names for <name> are:
@table @code
@item sha1
The SHA-1 hash algorithm
@item sha256
The SHA-256 hash algorithm
@item rmd160
The RIPE-MD160 hash algorithm
@item md5
The old and broken MD5 hash algorithm
@item tls-md5sha1
A combined hash algorithm as used by the TLS protocol.
@end table
@noindent
The actual signing is done using
@example
PKSIGN <options>
@end example
Options are not yet defined, but may later be used to choose among
different algorithms. The agent does then some checks, asks for the
passphrase and as a result the server returns the signature as an SPKI
like S-expression in "D" lines:
@example
(sig-val
(<algo>
(<param_name1> <mpi>)
...
(<param_namen> <mpi>)))
@end example
The operation is affected by the option
@example
OPTION use-cache-for-signing=0|1
@end example
The default of @code{1} uses the cache. Setting this option to @code{0}
will lead @command{gpg-agent} to ignore the passphrase cache. Note, that there is
also a global command line option for @command{gpg-agent} to globally disable the
caching.
Here is an example session:
@cartouche
@smallexample
C: SIGKEY <keyGrip>
S: OK key available
C: SIGKEY <keyGrip>
S: OK key available
C: PKSIGN
S: # I did ask the user whether he really wants to sign
S: # I did ask the user for the passphrase
S: INQUIRE HASHVAL
C: D ABCDEF012345678901234
C: END
S: # signature follows
S: D (sig-val rsa (s 45435453654612121212))
S: OK
@end smallexample
@end cartouche
@node Agent GENKEY
@subsection Generating a Key
This is used to create a new keypair and store the secret key inside the
active PSE --- which is in most cases a Soft-PSE. A not-yet-defined
option allows choosing the storage location. To get the secret key out
of the PSE, a special export tool has to be used.
@example
GENKEY [--no-protection] [--preset] [<cache_nonce>]
@end example
Invokes the key generation process and the server will then inquire
on the generation parameters, like:
@example
S: INQUIRE KEYPARM
C: D (genkey (rsa (nbits 1024)))
C: END
@end example
The format of the key parameters which depends on the algorithm is of
the form:
@example
(genkey
(algo
(parameter_name_1 ....)
....
(parameter_name_n ....)))
@end example
If everything succeeds, the server returns the *public key* in a SPKI
like S-Expression like this:
@example
(public-key
(rsa
(n <mpi>)
(e <mpi>)))
@end example
Here is an example session:
@cartouche
@smallexample
C: GENKEY
S: INQUIRE KEYPARM
C: D (genkey (rsa (nbits 1024)))
C: END
S: D (public-key
S: D (rsa (n 326487324683264) (e 10001)))
S OK key created
@end smallexample
@end cartouche
The @option{--no-protection} option may be used to prevent prompting for a
passphrase to protect the secret key while leaving the secret key unprotected.
The @option{--preset} option may be used to add the passphrase to the cache
using the default cache parameters.
The @option{--inq-passwd} option may be used to create the key with a
supplied passphrase. When used the agent does an inquiry with the
keyword @code{NEWPASSWD} to retrieve that passphrase. This option
takes precedence over @option{--no-protection}; however if the client
sends a empty (zero-length) passphrase, this is identical to
@option{--no-protection}.
@node Agent IMPORT
@subsection Importing a Secret Key
This operation is not yet supported by GpgAgent. Specialized tools
are to be used for this.
There is no actual need because we can expect that secret keys
created by a 3rd party are stored on a smartcard. If we have
generated the key ourselves, we do not need to import it.
@node Agent EXPORT
@subsection Export a Secret Key
Not implemented.
Should be done by an extra tool.
@node Agent ISTRUSTED
@subsection Importing a Root Certificate
Actually we do not import a Root Cert but provide a way to validate
any piece of data by storing its Hash along with a description and
an identifier in the PSE. Here is the interface description:
@example
ISTRUSTED <fingerprint>
@end example
Check whether the OpenPGP primary key or the X.509 certificate with the
given fingerprint is an ultimately trusted key or a trusted Root CA
certificate. The fingerprint should be given as a hexstring (without
any blanks or colons or whatever in between) and may be left padded with
00 in case of an MD5 fingerprint. GPGAgent will answer with:
@example
OK
@end example
The key is in the table of trusted keys.
@example
ERR 304 (Not Trusted)
@end example
The key is not in this table.
Gpg needs the entire list of trusted keys to maintain the web of
trust; the following command is therefore quite helpful:
@example
LISTTRUSTED
@end example
GpgAgent returns a list of trusted keys line by line:
@example
S: D 000000001234454556565656677878AF2F1ECCFF P
S: D 340387563485634856435645634856438576457A P
S: D FEDC6532453745367FD83474357495743757435D S
S: OK
@end example
The first item on a line is the hexified fingerprint where MD5
fingerprints are @code{00} padded to the left and the second item is a
flag to indicate the type of key (so that gpg is able to only take care
of PGP keys). P = OpenPGP, S = S/MIME. A client should ignore the rest
of the line, so that we can extend the format in the future.
Finally a client should be able to mark a key as trusted:
@example
MARKTRUSTED @var{fingerprint} "P"|"S"
@end example
The server will then pop up a window to ask the user whether she
really trusts this key. For this it will probably ask for a text to
be displayed like this:
@example
S: INQUIRE TRUSTDESC
C: D Do you trust the key with the fingerprint @@FPR@@
C: D bla fasel blurb.
C: END
S: OK
@end example
Known sequences with the pattern @@foo@@ are replaced according to this
table:
@table @code
@item @@FPR16@@
Format the fingerprint according to gpg rules for a v3 keys.
@item @@FPR20@@
Format the fingerprint according to gpg rules for a v4 keys.
@item @@FPR@@
Choose an appropriate format to format the fingerprint.
@item @@@@
Replaced by a single @code{@@}.
@end table
@node Agent GET_PASSPHRASE
@subsection Ask for a passphrase
This function is usually used to ask for a passphrase to be used for
symmetric encryption, but may also be used by programs which need
special handling of passphrases. This command uses a syntax which helps
clients to use the agent with minimum effort.
@example
GET_PASSPHRASE [--data] [--check] [--no-ask] [--repeat[=N]] \
[--qualitybar] @var{cache_id} \
[@var{error_message} @var{prompt} @var{description}]
@end example
@var{cache_id} is expected to be a string used to identify a cached
passphrase. Use a @code{X} to bypass the cache. With no other
arguments the agent returns a cached passphrase or an error. By
convention either the hexified fingerprint of the key shall be used for
@var{cache_id} or an arbitrary string prefixed with the name of the
calling application and a colon: Like @code{gpg:somestring}.
@var{error_message} is either a single @code{X} for no error message or
a string to be shown as an error message like (e.g. "invalid
passphrase"). Blanks must be percent escaped or replaced by @code{+}'.
@var{prompt} is either a single @code{X} for a default prompt or the
text to be shown as the prompt. Blanks must be percent escaped or
replaced by @code{+}.
@var{description} is a text shown above the entry field. Blanks must be
percent escaped or replaced by @code{+}.
The agent either returns with an error or with a OK followed by the hex
encoded passphrase. Note that the length of the strings is implicitly
limited by the maximum length of a command. If the option
@option{--data} is used, the passphrase is not returned on the OK line
but by regular data lines; this is the preferred method.
If the option @option{--check} is used, the standard passphrase
constraints checks are applied. A check is not done if the passphrase
has been found in the cache.
If the option @option{--no-ask} is used and the passphrase is not in the
cache the user will not be asked to enter a passphrase but the error
code @code{GPG_ERR_NO_DATA} is returned.
If the option @option{--qualitybar} is used and a minimum passphrase
length has been configured, a visual indication of the entered
passphrase quality is shown.
@example
CLEAR_PASSPHRASE @var{cache_id}
@end example
may be used to invalidate the cache entry for a passphrase. The
function returns with OK even when there is no cached passphrase.
@node Agent CLEAR_PASSPHRASE
@subsection Remove a cached passphrase
Use this command to remove a cached passphrase.
@example
CLEAR_PASSPHRASE [--mode=normal] <cache_id>
@end example
The @option{--mode=normal} option can be used to clear a @var{cache_id} that
was set by gpg-agent.
@node Agent PRESET_PASSPHRASE
@subsection Set a passphrase for a keygrip
This command adds a passphrase to the cache for the specified @var{keygrip}.
@example
PRESET_PASSPHRASE [--inquire] <string_or_keygrip> <timeout> [<hexstring>]
@end example
The passphrase is a hexadecimal string when specified. When not specified, the
passphrase will be retrieved from the pinentry module unless the
@option{--inquire} option was specified in which case the passphrase will be
retrieved from the client.
The @var{timeout} parameter keeps the passphrase cached for the specified
number of seconds. A value of @code{-1} means infinite while @code{0} means
the default (currently only a timeout of -1 is allowed, which means to never
expire it).
@node Agent GET_CONFIRMATION
@subsection Ask for confirmation
This command may be used to ask for a simple confirmation by
presenting a text and 2 buttons: Okay and Cancel.
@example
GET_CONFIRMATION @var{description}
@end example
@var{description}is displayed along with a Okay and Cancel
button. Blanks must be percent escaped or replaced by @code{+}. A
@code{X} may be used to display confirmation dialog with a default
text.
The agent either returns with an error or with a OK. Note, that the
length of @var{description} is implicitly limited by the maximum
length of a command.
@node Agent HAVEKEY
@subsection Check whether a key is available
This can be used to see whether a secret key is available. It does
not return any information on whether the key is somehow protected.
@example
HAVEKEY @var{keygrips}
@end example
The agent answers either with OK or @code{No_Secret_Key} (208). The
caller may want to check for other error codes as well. More than one
keygrip may be given. In this case the command returns success if at
least one of the keygrips corresponds to an available secret key.
@node Agent LEARN
@subsection Register a smartcard
@example
LEARN [--send]
@end example
This command is used to register a smartcard. With the @option{--send}
option given the certificates are sent back.
@node Agent PASSWD
@subsection Change a Passphrase
@example
PASSWD [--cache-nonce=<c>] [--passwd-nonce=<s>] [--preset] @var{keygrip}
@end example
This command is used to interactively change the passphrase of the key
identified by the hex string @var{keygrip}. The @option{--preset}
option may be used to add the new passphrase to the cache using the
default cache parameters.
@node Agent UPDATESTARTUPTTY
@subsection Change the standard display
@example
UPDATESTARTUPTTY
@end example
Set the startup TTY and X-DISPLAY variables to the values of this
session. This command is useful to direct future pinentry invocations
to another screen. It is only required because there is no way in the
ssh-agent protocol to convey this information.
@node Agent GETEVENTCOUNTER
@subsection Get the Event Counters
@example
GETEVENTCOUNTER
@end example
This function return one status line with the current values of the
event counters. The event counters are useful to avoid polling by
delaying a poll until something has changed. The values are decimal
numbers in the range @code{0} to @code{UINT_MAX} and wrapping around to
0. The actual values should not be relied upon; they shall only be used
to detect a change.
The currently defined counters are:
@table @code
@item ANY
Incremented with any change of any of the other counters.
@item KEY
Incremented for added or removed private keys.
@item CARD
Incremented for each change of the card reader's status.
@end table
@node Agent GETINFO
@subsection Return information about the process
This is a multipurpose function to return a variety of information.
@example
GETINFO @var{what}
@end example
The value of @var{what} specifies the kind of information returned:
@table @code
@item version
Return the version of the program.
@item pid
Return the process id of the process.
@item socket_name
Return the name of the socket used to connect the agent.
@item ssh_socket_name
Return the name of the socket used for SSH connections. If SSH support
has not been enabled the error @code{GPG_ERR_NO_DATA} will be returned.
@end table
@node Agent OPTION
@subsection Set options for the session
Here is a list of session options which are not yet described with
other commands. The general syntax for an Assuan option is:
@smallexample
OPTION @var{key}=@var{value}
@end smallexample
@noindent
Supported @var{key}s are:
@table @code
@item agent-awareness
This may be used to tell gpg-agent of which gpg-agent version the
client is aware of. gpg-agent uses this information to enable
features which might break older clients.
@item putenv
Change the session's environment to be used for the
Pinentry. Valid values are:
@table @code
@item @var{name}
Delete envvar @var{name}
@item @var{name}=
Set envvar @var{name} to the empty string
@item @var{name}=@var{value}
Set envvar @var{name} to the string @var{value}.
@end table
@item use-cache-for-signing
See Assuan command @code{PKSIGN}.
@item allow-pinentry-notify
This does not need any value. It is used to enable the
PINENTRY_LAUNCHED inquiry.
@item pinentry-mode
This option is used to change the operation mode of the pinentry. The
following values are defined:
@table @code
@item ask
This is the default mode which pops up a pinentry as needed.
@item cancel
Instead of popping up a pinentry, return the error code
@code{GPG_ERR_CANCELED}.
@item error
Instead of popping up a pinentry, return the error code
@code{GPG_ERR_NO_PIN_ENTRY}.
@item loopback
Use a loopback pinentry. This fakes a pinentry by using inquiries
back to the caller to ask for a passphrase. This option may only be
set if the agent has been configured for that.
To disable this feature use @ref{option --no-allow-loopback-pinentry}.
@end table
@item cache-ttl-opt-preset
This option sets the cache TTL for new entries created by GENKEY and
PASSWD commands when using the @option{--preset} option. It is not
used a default value is used.
@item s2k-count
Instead of using the standard S2K count (which is computed on the
fly), the given S2K count is used for new keys or when changing the
passphrase of a key. Values below 65536 are considered to be 0. This
option is valid for the entire session or until reset to 0. This
option is useful if the key is later used on boxes which are either
much slower or faster than the actual box.
@item pretend-request-origin
This option switches the connection into a restricted mode which
handles all further commands in the same way as they would be handled
when originating from the extra or browser socket. Note that this
option is not available in the restricted mode. Valid values for this
option are:
@table @code
@item none
@itemx local
This is a NOP and leaves the connection in the standard way.
@item remote
Pretend to come from a remote origin in the same way as connections
from the @option{--extra-socket}.
@item browser
Pretend to come from a local web browser in the same way as connections
from the @option{--browser-socket}.
@end table
@end table
@mansect see also
@ifset isman
@command{@gpgname}(1),
@command{gpgsm}(1),
@command{gpgconf}(1),
@command{gpg-connect-agent}(1),
@command{scdaemon}(1)
@end ifset
@include see-also-note.texi
|