summaryrefslogtreecommitdiff
path: root/cipher/cipher.c
blob: 3a8597f5d1bd23c490bb8075b04d37d8a66e7bea (plain)
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
/* cipher.c  -	cipher dispatcher
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
 *               2005, 2007, 2008, 2009, 2011 Free Software Foundation, Inc.
 * Copyright (C) 2013 g10 Code GmbH
 *
 * This file is part of Libgcrypt.
 *
 * Libgcrypt is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser general Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * Libgcrypt is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "g10lib.h"
#include "../src/gcrypt-testapi.h"
#include "cipher.h"
#include "./cipher-internal.h"


/* This is the list of the default ciphers, which are included in
   libgcrypt.  */
static gcry_cipher_spec_t *cipher_list[] =
  {
#if USE_BLOWFISH
     &_gcry_cipher_spec_blowfish,
#endif
#if USE_DES
     &_gcry_cipher_spec_des,
     &_gcry_cipher_spec_tripledes,
#endif
#if USE_ARCFOUR
     &_gcry_cipher_spec_arcfour,
#endif
#if USE_CAST5
     &_gcry_cipher_spec_cast5,
#endif
#if USE_AES
     &_gcry_cipher_spec_aes,
     &_gcry_cipher_spec_aes192,
     &_gcry_cipher_spec_aes256,
#endif
#if USE_TWOFISH
     &_gcry_cipher_spec_twofish,
     &_gcry_cipher_spec_twofish128,
#endif
#if USE_SERPENT
     &_gcry_cipher_spec_serpent128,
     &_gcry_cipher_spec_serpent192,
     &_gcry_cipher_spec_serpent256,
#endif
#if USE_RFC2268
     &_gcry_cipher_spec_rfc2268_40,
     &_gcry_cipher_spec_rfc2268_128,
#endif
#if USE_SEED
     &_gcry_cipher_spec_seed,
#endif
#if USE_CAMELLIA
     &_gcry_cipher_spec_camellia128,
     &_gcry_cipher_spec_camellia192,
     &_gcry_cipher_spec_camellia256,
#endif
#ifdef USE_IDEA
     &_gcry_cipher_spec_idea,
#endif
#if USE_SALSA20
     &_gcry_cipher_spec_salsa20,
     &_gcry_cipher_spec_salsa20r12,
#endif
#if USE_GOST28147
     &_gcry_cipher_spec_gost28147,
#endif
#if USE_CHACHA20
     &_gcry_cipher_spec_chacha20,
#endif
    NULL
  };




static int
map_algo (int algo)
{
  return algo;
}


/* Return the spec structure for the cipher algorithm ALGO.  For
   an unknown algorithm NULL is returned.  */
static gcry_cipher_spec_t *
spec_from_algo (int algo)
{
  int idx;
  gcry_cipher_spec_t *spec;

  algo = map_algo (algo);

  for (idx = 0; (spec = cipher_list[idx]); idx++)
    if (algo == spec->algo)
      return spec;
  return NULL;
}


/* Lookup a cipher's spec by its name.  */
static gcry_cipher_spec_t *
spec_from_name (const char *name)
{
  gcry_cipher_spec_t *spec;
  int idx;
  const char **aliases;

  for (idx=0; (spec = cipher_list[idx]); idx++)
    {
      if (!stricmp (name, spec->name))
        return spec;
      if (spec->aliases)
        {
          for (aliases = spec->aliases; *aliases; aliases++)
            if (!stricmp (name, *aliases))
              return spec;
        }
    }

  return NULL;
}


/* Lookup a cipher's spec by its OID.  */
static gcry_cipher_spec_t *
spec_from_oid (const char *oid)
{
  gcry_cipher_spec_t *spec;
  gcry_cipher_oid_spec_t *oid_specs;
  int idx, j;

  for (idx=0; (spec = cipher_list[idx]); idx++)
    {
      oid_specs = spec->oids;
      if (oid_specs)
        {
          for (j = 0; oid_specs[j].oid; j++)
            if (!stricmp (oid, oid_specs[j].oid))
              return spec;
        }
    }

  return NULL;
}


/* Locate the OID in the oid table and return the spec or NULL if not
   found.  An optional "oid." or "OID." prefix in OID is ignored, the
   OID is expected to be in standard IETF dotted notation.  A pointer
   to the OID specification of the module implementing this algorithm
   is return in OID_SPEC unless passed as NULL.*/
static gcry_cipher_spec_t *
search_oid (const char *oid, gcry_cipher_oid_spec_t *oid_spec)
{
  gcry_cipher_spec_t *spec;
  int i;

  if (oid && ((! strncmp (oid, "oid.", 4))
	      || (! strncmp (oid, "OID.", 4))))
    oid += 4;

  spec = spec_from_oid (oid);
  if (spec && spec->oids)
    {
      for (i = 0; spec->oids[i].oid; i++)
	if (!stricmp (oid, spec->oids[i].oid))
	  {
	    if (oid_spec)
	      *oid_spec = spec->oids[i];
            return spec;
	  }
    }

  return NULL;
}


/* Map STRING to the cipher algorithm identifier.  Returns the
   algorithm ID of the cipher for the given name or 0 if the name is
   not known.  It is valid to pass NULL for STRING which results in a
   return value of 0. */
int
_gcry_cipher_map_name (const char *string)
{
  gcry_cipher_spec_t *spec;

  if (!string)
    return 0;

  /* If the string starts with a digit (optionally prefixed with
     either "OID." or "oid."), we first look into our table of ASN.1
     object identifiers to figure out the algorithm */

  spec = search_oid (string, NULL);
  if (spec)
    return spec->algo;

  spec = spec_from_name (string);
  if (spec)
    return spec->algo;

  return 0;
}


/* Given a STRING with an OID in dotted decimal notation, this
   function returns the cipher mode (GCRY_CIPHER_MODE_*) associated
   with that OID or 0 if no mode is known.  Passing NULL for string
   yields a return value of 0. */
int
_gcry_cipher_mode_from_oid (const char *string)
{
  gcry_cipher_spec_t *spec;
  gcry_cipher_oid_spec_t oid_spec;

  if (!string)
    return 0;

  spec = search_oid (string, &oid_spec);
  if (spec)
    return oid_spec.mode;

  return 0;
}


/* Map the cipher algorithm identifier ALGORITHM to a string
   representing this algorithm.  This string is the default name as
   used by Libgcrypt.  A "?" is returned for an unknown algorithm.
   NULL is never returned. */
const char *
_gcry_cipher_algo_name (int algorithm)
{
  gcry_cipher_spec_t *spec;

  spec = spec_from_algo (algorithm);
  return spec? spec->name : "?";
}


/* Flag the cipher algorithm with the identifier ALGORITHM as
   disabled.  There is no error return, the function does nothing for
   unknown algorithms.  Disabled algorithms are virtually not
   available in Libgcrypt.  This is not thread safe and should thus be
   called early. */
static void
disable_cipher_algo (int algo)
{
  gcry_cipher_spec_t *spec = spec_from_algo (algo);

  if (spec)
    spec->flags.disabled = 1;
}


/* Return 0 if the cipher algorithm with identifier ALGORITHM is
   available. Returns a basic error code value if it is not
   available.  */
static gcry_err_code_t
check_cipher_algo (int algorithm)
{
  gcry_cipher_spec_t *spec;

  spec = spec_from_algo (algorithm);
  if (spec && !spec->flags.disabled)
    return 0;

  return GPG_ERR_CIPHER_ALGO;
}


/* Return the standard length in bits of the key for the cipher
   algorithm with the identifier ALGORITHM.  */
static unsigned int
cipher_get_keylen (int algorithm)
{
  gcry_cipher_spec_t *spec;
  unsigned len = 0;

  spec = spec_from_algo (algorithm);
  if (spec)
    {
      len = spec->keylen;
      if (!len)
	log_bug ("cipher %d w/o key length\n", algorithm);
    }

  return len;
}


/* Return the block length of the cipher algorithm with the identifier
   ALGORITHM.  This function return 0 for an invalid algorithm.  */
static unsigned int
cipher_get_blocksize (int algorithm)
{
  gcry_cipher_spec_t *spec;
  unsigned len = 0;

  spec = spec_from_algo (algorithm);
  if (spec)
    {
      len = spec->blocksize;
      if (!len)
        log_bug ("cipher %d w/o blocksize\n", algorithm);
    }

  return len;
}


/*
   Open a cipher handle for use with cipher algorithm ALGORITHM, using
   the cipher mode MODE (one of the GCRY_CIPHER_MODE_*) and return a
   handle in HANDLE.  Put NULL into HANDLE and return an error code if
   something goes wrong.  FLAGS may be used to modify the
   operation.  The defined flags are:

   GCRY_CIPHER_SECURE:  allocate all internal buffers in secure memory.
   GCRY_CIPHER_ENABLE_SYNC:  Enable the sync operation as used in OpenPGP.
   GCRY_CIPHER_CBC_CTS:  Enable CTS mode.
   GCRY_CIPHER_CBC_MAC:  Enable MAC mode.

   Values for these flags may be combined using OR.
 */
gcry_err_code_t
_gcry_cipher_open (gcry_cipher_hd_t *handle,
                   int algo, int mode, unsigned int flags)
{
  gcry_err_code_t rc;
  gcry_cipher_hd_t h = NULL;

  if (mode >= GCRY_CIPHER_MODE_INTERNAL)
    rc = GPG_ERR_INV_CIPHER_MODE;
  else
    rc = _gcry_cipher_open_internal (&h, algo, mode, flags);

  *handle = rc ? NULL : h;

  return rc;
}


gcry_err_code_t
_gcry_cipher_open_internal (gcry_cipher_hd_t *handle,
			    int algo, int mode, unsigned int flags)
{
  int secure = (flags & GCRY_CIPHER_SECURE);
  gcry_cipher_spec_t *spec;
  gcry_cipher_hd_t h = NULL;
  gcry_err_code_t err;

  /* If the application missed to call the random poll function, we do
     it here to ensure that it is used once in a while. */
  _gcry_fast_random_poll ();

  spec = spec_from_algo (algo);
  if (!spec)
    err = GPG_ERR_CIPHER_ALGO;
  else if (spec->flags.disabled)
    err = GPG_ERR_CIPHER_ALGO;
  else
    err = 0;

  /* check flags */
  if ((! err)
      && ((flags & ~(0
		     | GCRY_CIPHER_SECURE
		     | GCRY_CIPHER_ENABLE_SYNC
		     | GCRY_CIPHER_CBC_CTS
		     | GCRY_CIPHER_CBC_MAC))
	  || (flags & GCRY_CIPHER_CBC_CTS & GCRY_CIPHER_CBC_MAC)))
    err = GPG_ERR_CIPHER_ALGO;

  /* check that a valid mode has been requested */
  if (! err)
    switch (mode)
      {
      case GCRY_CIPHER_MODE_CCM:
	if (spec->blocksize != GCRY_CCM_BLOCK_LEN)
	  err = GPG_ERR_INV_CIPHER_MODE;
	if (!spec->encrypt || !spec->decrypt)
	  err = GPG_ERR_INV_CIPHER_MODE;
	break;

      case GCRY_CIPHER_MODE_ECB:
      case GCRY_CIPHER_MODE_CBC:
      case GCRY_CIPHER_MODE_CFB:
      case GCRY_CIPHER_MODE_OFB:
      case GCRY_CIPHER_MODE_CTR:
      case GCRY_CIPHER_MODE_AESWRAP:
      case GCRY_CIPHER_MODE_CMAC:
      case GCRY_CIPHER_MODE_GCM:
	if (!spec->encrypt || !spec->decrypt)
	  err = GPG_ERR_INV_CIPHER_MODE;
	break;

      case GCRY_CIPHER_MODE_POLY1305:
	if (!spec->stencrypt || !spec->stdecrypt || !spec->setiv)
	  err = GPG_ERR_INV_CIPHER_MODE;
	else if (spec->algo != GCRY_CIPHER_CHACHA20)
	  err = GPG_ERR_INV_CIPHER_MODE;
	break;

      case GCRY_CIPHER_MODE_OCB:
        /* Note that our implementation allows only for 128 bit block
           length algorithms.  Lower block lengths would be possible
           but we do not implement them because they limit the
           security too much.  */
	if (!spec->encrypt || !spec->decrypt)
	  err = GPG_ERR_INV_CIPHER_MODE;
	else if (spec->blocksize != (128/8))
	  err = GPG_ERR_INV_CIPHER_MODE;
	break;

      case GCRY_CIPHER_MODE_STREAM:
	if (!spec->stencrypt || !spec->stdecrypt)
	  err = GPG_ERR_INV_CIPHER_MODE;
	break;

      case GCRY_CIPHER_MODE_NONE:
        /* This mode may be used for debugging.  It copies the main
           text verbatim to the ciphertext.  We do not allow this in
           fips mode or if no debug flag has been set.  */
	if (fips_mode () || !_gcry_get_debug_flag (0))
          err = GPG_ERR_INV_CIPHER_MODE;
	break;

      default:
	err = GPG_ERR_INV_CIPHER_MODE;
      }

  /* Perform selftest here and mark this with a flag in cipher_table?
     No, we should not do this as it takes too long.  Further it does
     not make sense to exclude algorithms with failing selftests at
     runtime: If a selftest fails there is something seriously wrong
     with the system and thus we better die immediately. */

  if (! err)
    {
      size_t size = (sizeof (*h)
                     + 2 * spec->contextsize
                     - sizeof (cipher_context_alignment_t)
#ifdef NEED_16BYTE_ALIGNED_CONTEXT
                     + 15  /* Space for leading alignment gap.  */
#endif /*NEED_16BYTE_ALIGNED_CONTEXT*/
                     );

      if (secure)
	h = xtrycalloc_secure (1, size);
      else
	h = xtrycalloc (1, size);

      if (! h)
	err = gpg_err_code_from_syserror ();
      else
	{
          size_t off = 0;

#ifdef NEED_16BYTE_ALIGNED_CONTEXT
          if ( ((uintptr_t)h & 0x0f) )
            {
              /* The malloced block is not aligned on a 16 byte
                 boundary.  Correct for this.  */
              off = 16 - ((uintptr_t)h & 0x0f);
              h = (void*)((char*)h + off);
            }
#endif /*NEED_16BYTE_ALIGNED_CONTEXT*/

	  h->magic = secure ? CTX_MAGIC_SECURE : CTX_MAGIC_NORMAL;
          h->actual_handle_size = size - off;
          h->handle_offset = off;
	  h->spec = spec;
          h->algo = algo;
	  h->mode = mode;
	  h->flags = flags;

          /* Setup bulk encryption routines.  */
          switch (algo)
            {
#ifdef USE_AES
            case GCRY_CIPHER_AES128:
            case GCRY_CIPHER_AES192:
            case GCRY_CIPHER_AES256:
              h->bulk.cfb_enc = _gcry_aes_cfb_enc;
              h->bulk.cfb_dec = _gcry_aes_cfb_dec;
              h->bulk.cbc_enc = _gcry_aes_cbc_enc;
              h->bulk.cbc_dec = _gcry_aes_cbc_dec;
              h->bulk.ctr_enc = _gcry_aes_ctr_enc;
              h->bulk.ocb_crypt = _gcry_aes_ocb_crypt;
              h->bulk.ocb_auth  = _gcry_aes_ocb_auth;
              break;
#endif /*USE_AES*/
#ifdef USE_BLOWFISH
	    case GCRY_CIPHER_BLOWFISH:
              h->bulk.cfb_dec = _gcry_blowfish_cfb_dec;
              h->bulk.cbc_dec = _gcry_blowfish_cbc_dec;
              h->bulk.ctr_enc = _gcry_blowfish_ctr_enc;
              break;
#endif /*USE_BLOWFISH*/
#ifdef USE_CAST5
	    case GCRY_CIPHER_CAST5:
              h->bulk.cfb_dec = _gcry_cast5_cfb_dec;
              h->bulk.cbc_dec = _gcry_cast5_cbc_dec;
              h->bulk.ctr_enc = _gcry_cast5_ctr_enc;
              break;
#endif /*USE_CAMELLIA*/
#ifdef USE_CAMELLIA
	    case GCRY_CIPHER_CAMELLIA128:
	    case GCRY_CIPHER_CAMELLIA192:
	    case GCRY_CIPHER_CAMELLIA256:
              h->bulk.cbc_dec = _gcry_camellia_cbc_dec;
              h->bulk.cfb_dec = _gcry_camellia_cfb_dec;
              h->bulk.ctr_enc = _gcry_camellia_ctr_enc;
              h->bulk.ocb_crypt = _gcry_camellia_ocb_crypt;
              h->bulk.ocb_auth  = _gcry_camellia_ocb_auth;
              break;
#endif /*USE_CAMELLIA*/
#ifdef USE_DES
            case GCRY_CIPHER_3DES:
              h->bulk.cbc_dec =  _gcry_3des_cbc_dec;
              h->bulk.cfb_dec =  _gcry_3des_cfb_dec;
              h->bulk.ctr_enc =  _gcry_3des_ctr_enc;
              break;
#endif /*USE_DES*/
#ifdef USE_SERPENT
	    case GCRY_CIPHER_SERPENT128:
	    case GCRY_CIPHER_SERPENT192:
	    case GCRY_CIPHER_SERPENT256:
              h->bulk.cbc_dec = _gcry_serpent_cbc_dec;
              h->bulk.cfb_dec = _gcry_serpent_cfb_dec;
              h->bulk.ctr_enc = _gcry_serpent_ctr_enc;
              h->bulk.ocb_crypt = _gcry_serpent_ocb_crypt;
              h->bulk.ocb_auth  = _gcry_serpent_ocb_auth;
              break;
#endif /*USE_SERPENT*/
#ifdef USE_TWOFISH
	    case GCRY_CIPHER_TWOFISH:
	    case GCRY_CIPHER_TWOFISH128:
              h->bulk.cbc_dec = _gcry_twofish_cbc_dec;
              h->bulk.cfb_dec = _gcry_twofish_cfb_dec;
              h->bulk.ctr_enc = _gcry_twofish_ctr_enc;
              h->bulk.ocb_crypt = _gcry_twofish_ocb_crypt;
              h->bulk.ocb_auth  = _gcry_twofish_ocb_auth;
              break;
#endif /*USE_TWOFISH*/

            default:
              break;
            }

          /* Setup defaults depending on the mode.  */
          switch (mode)
            {
            case GCRY_CIPHER_MODE_OCB:
              h->u_mode.ocb.taglen = 16; /* Bytes.  */
              break;

            default:
              break;
            }

	}
    }

  /* Done.  */

  *handle = err ? NULL : h;

  return err;
}


/* Release all resources associated with the cipher handle H. H may be
   NULL in which case this is a no-operation. */
void
_gcry_cipher_close (gcry_cipher_hd_t h)
{
  size_t off;

  if (!h)
    return;

  if ((h->magic != CTX_MAGIC_SECURE)
      && (h->magic != CTX_MAGIC_NORMAL))
    _gcry_fatal_error(GPG_ERR_INTERNAL,
		      "gcry_cipher_close: already closed/invalid handle");
  else
    h->magic = 0;

  /* We always want to wipe out the memory even when the context has
     been allocated in secure memory.  The user might have disabled
     secure memory or is using his own implementation which does not
     do the wiping.  To accomplish this we need to keep track of the
     actual size of this structure because we have no way to known
     how large the allocated area was when using a standard malloc. */
  off = h->handle_offset;
  wipememory (h, h->actual_handle_size);

  xfree ((char*)h - off);
}


/* Set the key to be used for the encryption context C to KEY with
   length KEYLEN.  The length should match the required length. */
static gcry_err_code_t
cipher_setkey (gcry_cipher_hd_t c, byte *key, size_t keylen)
{
  gcry_err_code_t rc;

  rc = c->spec->setkey (&c->context.c, key, keylen);
  if (!rc)
    {
      /* Duplicate initial context.  */
      memcpy ((void *) ((char *) &c->context.c + c->spec->contextsize),
              (void *) &c->context.c,
              c->spec->contextsize);
      c->marks.key = 1;

      switch (c->mode)
        {
        case GCRY_CIPHER_MODE_CMAC:
          _gcry_cipher_cmac_set_subkeys (c);
          break;

        case GCRY_CIPHER_MODE_GCM:
          _gcry_cipher_gcm_setkey (c);
          break;

        case GCRY_CIPHER_MODE_POLY1305:
          _gcry_cipher_poly1305_setkey (c);
          break;

        default:
          break;
        };
    }
  else
    c->marks.key = 0;

  return rc;
}


/* Set the IV to be used for the encryption context C to IV with
   length IVLEN.  The length should match the required length. */
static gcry_err_code_t
cipher_setiv (gcry_cipher_hd_t c, const byte *iv, size_t ivlen)
{
  /* If the cipher has its own IV handler, we use only this one.  This
     is currently used for stream ciphers requiring a nonce.  */
  if (c->spec->setiv)
    {
      c->spec->setiv (&c->context.c, iv, ivlen);
      return 0;
    }

  memset (c->u_iv.iv, 0, c->spec->blocksize);
  if (iv)
    {
      if (ivlen != c->spec->blocksize)
        {
          log_info ("WARNING: cipher_setiv: ivlen=%u blklen=%u\n",
                    (unsigned int)ivlen, (unsigned int)c->spec->blocksize);
          fips_signal_error ("IV length does not match blocklength");
        }
      if (ivlen > c->spec->blocksize)
        ivlen = c->spec->blocksize;
      memcpy (c->u_iv.iv, iv, ivlen);
      c->marks.iv = 1;
    }
  else
      c->marks.iv = 0;
  c->unused = 0;

  return 0;
}


/* Reset the cipher context to the initial context.  This is basically
   the same as an release followed by a new. */
static void
cipher_reset (gcry_cipher_hd_t c)
{
  unsigned int marks_key;

  marks_key = c->marks.key;

  memcpy (&c->context.c,
	  (char *) &c->context.c + c->spec->contextsize,
	  c->spec->contextsize);
  memset (&c->marks, 0, sizeof c->marks);
  memset (c->u_iv.iv, 0, c->spec->blocksize);
  memset (c->lastiv, 0, c->spec->blocksize);
  memset (c->u_ctr.ctr, 0, c->spec->blocksize);
  c->unused = 0;

  c->marks.key = marks_key;

  switch (c->mode)
    {
    case GCRY_CIPHER_MODE_CMAC:
      /* Only clear 'tag' for cmac, keep subkeys. */
      c->u_mode.cmac.tag = 0;
      break;

    case GCRY_CIPHER_MODE_GCM:
      /* Only clear head of u_mode, keep ghash_key and gcm_table. */
      {
        byte *u_mode_pos = (void *)&c->u_mode;
        byte *ghash_key_pos = c->u_mode.gcm.u_ghash_key.key;
        size_t u_mode_head_length = ghash_key_pos - u_mode_pos;

        memset (&c->u_mode, 0, u_mode_head_length);
      }
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      memset (&c->u_mode.poly1305, 0, sizeof c->u_mode.poly1305);
      break;

    case GCRY_CIPHER_MODE_CCM:
      memset (&c->u_mode.ccm, 0, sizeof c->u_mode.ccm);
      break;

    case GCRY_CIPHER_MODE_OCB:
      memset (&c->u_mode.ocb, 0, sizeof c->u_mode.ocb);
      /* Setup default taglen.  */
      c->u_mode.ocb.taglen = 16;
      break;

    default:
      break; /* u_mode unused by other modes. */
    }
}



static gcry_err_code_t
do_ecb_crypt (gcry_cipher_hd_t c,
              unsigned char *outbuf, size_t outbuflen,
              const unsigned char *inbuf, size_t inbuflen,
              gcry_cipher_encrypt_t crypt_fn)
{
  unsigned int blocksize = c->spec->blocksize;
  size_t n, nblocks;
  unsigned int burn, nburn;

  if (outbuflen < inbuflen)
    return GPG_ERR_BUFFER_TOO_SHORT;
  if ((inbuflen % blocksize))
    return GPG_ERR_INV_LENGTH;

  nblocks = inbuflen / blocksize;
  burn = 0;

  for (n=0; n < nblocks; n++ )
    {
      nburn = crypt_fn (&c->context.c, outbuf, inbuf);
      burn = nburn > burn ? nburn : burn;
      inbuf  += blocksize;
      outbuf += blocksize;
    }

  if (burn > 0)
    _gcry_burn_stack (burn + 4 * sizeof(void *));

  return 0;
}

static gcry_err_code_t
do_ecb_encrypt (gcry_cipher_hd_t c,
                unsigned char *outbuf, size_t outbuflen,
                const unsigned char *inbuf, size_t inbuflen)
{
  return do_ecb_crypt (c, outbuf, outbuflen, inbuf, inbuflen, c->spec->encrypt);
}

static gcry_err_code_t
do_ecb_decrypt (gcry_cipher_hd_t c,
                unsigned char *outbuf, size_t outbuflen,
                const unsigned char *inbuf, size_t inbuflen)
{
  return do_ecb_crypt (c, outbuf, outbuflen, inbuf, inbuflen, c->spec->decrypt);
}


/****************
 * Encrypt INBUF to OUTBUF with the mode selected at open.
 * inbuf and outbuf may overlap or be the same.
 * Depending on the mode some constraints apply to INBUFLEN.
 */
static gcry_err_code_t
cipher_encrypt (gcry_cipher_hd_t c, byte *outbuf, size_t outbuflen,
		const byte *inbuf, size_t inbuflen)
{
  gcry_err_code_t rc;

  switch (c->mode)
    {
    case GCRY_CIPHER_MODE_ECB:
      rc = do_ecb_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CBC:
      rc = _gcry_cipher_cbc_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CFB:
      rc = _gcry_cipher_cfb_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_OFB:
      rc = _gcry_cipher_ofb_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CTR:
      rc = _gcry_cipher_ctr_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_AESWRAP:
      rc = _gcry_cipher_aeswrap_encrypt (c, outbuf, outbuflen,
                                         inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CCM:
      rc = _gcry_cipher_ccm_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CMAC:
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;

    case GCRY_CIPHER_MODE_GCM:
      rc = _gcry_cipher_gcm_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      rc = _gcry_cipher_poly1305_encrypt (c, outbuf, outbuflen,
					  inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_OCB:
      rc = _gcry_cipher_ocb_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_STREAM:
      c->spec->stencrypt (&c->context.c,
                          outbuf, (byte*)/*arggg*/inbuf, inbuflen);
      rc = 0;
      break;

    case GCRY_CIPHER_MODE_NONE:
      if (fips_mode () || !_gcry_get_debug_flag (0))
        {
          fips_signal_error ("cipher mode NONE used");
          rc = GPG_ERR_INV_CIPHER_MODE;
        }
      else
        {
          if (inbuf != outbuf)
            memmove (outbuf, inbuf, inbuflen);
          rc = 0;
        }
      break;

    default:
      log_fatal ("cipher_encrypt: invalid mode %d\n", c->mode );
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;
    }

  return rc;
}


/****************
 * Encrypt IN and write it to OUT.  If IN is NULL, in-place encryption has
 * been requested.
 */
gcry_err_code_t
_gcry_cipher_encrypt (gcry_cipher_hd_t h, void *out, size_t outsize,
                      const void *in, size_t inlen)
{
  gcry_err_code_t rc;

  if (!in)  /* Caller requested in-place encryption.  */
    {
      in = out;
      inlen = outsize;
    }

  rc = cipher_encrypt (h, out, outsize, in, inlen);

  /* Failsafe: Make sure that the plaintext will never make it into
     OUT if the encryption returned an error.  */
  if (rc && out)
    memset (out, 0x42, outsize);

  return rc;
}



/****************
 * Decrypt INBUF to OUTBUF with the mode selected at open.
 * inbuf and outbuf may overlap or be the same.
 * Depending on the mode some some contraints apply to INBUFLEN.
 */
static gcry_err_code_t
cipher_decrypt (gcry_cipher_hd_t c, byte *outbuf, size_t outbuflen,
                const byte *inbuf, size_t inbuflen)
{
  gcry_err_code_t rc;

  switch (c->mode)
    {
    case GCRY_CIPHER_MODE_ECB:
      rc = do_ecb_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CBC:
      rc = _gcry_cipher_cbc_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CFB:
      rc = _gcry_cipher_cfb_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_OFB:
      rc = _gcry_cipher_ofb_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CTR:
      rc = _gcry_cipher_ctr_encrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_AESWRAP:
      rc = _gcry_cipher_aeswrap_decrypt (c, outbuf, outbuflen,
                                         inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CCM:
      rc = _gcry_cipher_ccm_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_CMAC:
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;

    case GCRY_CIPHER_MODE_GCM:
      rc = _gcry_cipher_gcm_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      rc = _gcry_cipher_poly1305_decrypt (c, outbuf, outbuflen,
					  inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_OCB:
      rc = _gcry_cipher_ocb_decrypt (c, outbuf, outbuflen, inbuf, inbuflen);
      break;

    case GCRY_CIPHER_MODE_STREAM:
      c->spec->stdecrypt (&c->context.c,
                          outbuf, (byte*)/*arggg*/inbuf, inbuflen);
      rc = 0;
      break;

    case GCRY_CIPHER_MODE_NONE:
      if (fips_mode () || !_gcry_get_debug_flag (0))
        {
          fips_signal_error ("cipher mode NONE used");
          rc = GPG_ERR_INV_CIPHER_MODE;
        }
      else
        {
          if (inbuf != outbuf)
            memmove (outbuf, inbuf, inbuflen);
          rc = 0;
        }
      break;

    default:
      log_fatal ("cipher_decrypt: invalid mode %d\n", c->mode );
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;
    }

  return rc;
}


gcry_err_code_t
_gcry_cipher_decrypt (gcry_cipher_hd_t h, void *out, size_t outsize,
                      const void *in, size_t inlen)
{
  if (!in) /* Caller requested in-place encryption. */
    {
      in = out;
      inlen = outsize;
    }

  return cipher_decrypt (h, out, outsize, in, inlen);
}



/****************
 * Used for PGP's somewhat strange CFB mode. Only works if
 * the corresponding flag is set.
 */
static void
cipher_sync (gcry_cipher_hd_t c)
{
  if ((c->flags & GCRY_CIPHER_ENABLE_SYNC) && c->unused)
    {
      memmove (c->u_iv.iv + c->unused,
               c->u_iv.iv, c->spec->blocksize - c->unused);
      memcpy (c->u_iv.iv,
              c->lastiv + c->spec->blocksize - c->unused, c->unused);
      c->unused = 0;
    }
}


gcry_err_code_t
_gcry_cipher_setkey (gcry_cipher_hd_t hd, const void *key, size_t keylen)
{
  return cipher_setkey (hd, (void*)key, keylen);
}


gcry_err_code_t
_gcry_cipher_setiv (gcry_cipher_hd_t hd, const void *iv, size_t ivlen)
{
  gcry_err_code_t rc = 0;

  switch (hd->mode)
    {
      case GCRY_CIPHER_MODE_CCM:
        rc = _gcry_cipher_ccm_set_nonce (hd, iv, ivlen);
        break;

      case GCRY_CIPHER_MODE_GCM:
        rc =  _gcry_cipher_gcm_setiv (hd, iv, ivlen);
        break;

      case GCRY_CIPHER_MODE_POLY1305:
        rc =  _gcry_cipher_poly1305_setiv (hd, iv, ivlen);
        break;

      case GCRY_CIPHER_MODE_OCB:
        rc = _gcry_cipher_ocb_set_nonce (hd, iv, ivlen);
        break;

      default:
        rc = cipher_setiv (hd, iv, ivlen);
        break;
    }
  return rc;
}

/* Set counter for CTR mode.  (CTR,CTRLEN) must denote a buffer of
   block size length, or (NULL,0) to set the CTR to the all-zero
   block. */
gpg_err_code_t
_gcry_cipher_setctr (gcry_cipher_hd_t hd, const void *ctr, size_t ctrlen)
{
  if (ctr && ctrlen == hd->spec->blocksize)
    {
      memcpy (hd->u_ctr.ctr, ctr, hd->spec->blocksize);
      hd->unused = 0;
    }
  else if (!ctr || !ctrlen)
    {
      memset (hd->u_ctr.ctr, 0, hd->spec->blocksize);
      hd->unused = 0;
    }
  else
    return GPG_ERR_INV_ARG;

  return 0;
}


gcry_err_code_t
_gcry_cipher_authenticate (gcry_cipher_hd_t hd, const void *abuf,
                           size_t abuflen)
{
  gcry_err_code_t rc;

  switch (hd->mode)
    {
    case GCRY_CIPHER_MODE_CCM:
      rc = _gcry_cipher_ccm_authenticate (hd, abuf, abuflen);
      break;

    case GCRY_CIPHER_MODE_CMAC:
      rc = _gcry_cipher_cmac_authenticate (hd, abuf, abuflen);
      break;

    case GCRY_CIPHER_MODE_GCM:
      rc = _gcry_cipher_gcm_authenticate (hd, abuf, abuflen);
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      rc = _gcry_cipher_poly1305_authenticate (hd, abuf, abuflen);
      break;

    case GCRY_CIPHER_MODE_OCB:
      rc = _gcry_cipher_ocb_authenticate (hd, abuf, abuflen);
      break;

    default:
      log_error ("gcry_cipher_authenticate: invalid mode %d\n", hd->mode);
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;
    }

  return rc;
}


gcry_err_code_t
_gcry_cipher_gettag (gcry_cipher_hd_t hd, void *outtag, size_t taglen)
{
  gcry_err_code_t rc;

  switch (hd->mode)
    {
    case GCRY_CIPHER_MODE_CCM:
      rc = _gcry_cipher_ccm_get_tag (hd, outtag, taglen);
      break;

    case GCRY_CIPHER_MODE_CMAC:
      rc = _gcry_cipher_cmac_get_tag (hd, outtag, taglen);
      break;

    case GCRY_CIPHER_MODE_GCM:
      rc = _gcry_cipher_gcm_get_tag (hd, outtag, taglen);
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      rc = _gcry_cipher_poly1305_get_tag (hd, outtag, taglen);
      break;

    case GCRY_CIPHER_MODE_OCB:
      rc = _gcry_cipher_ocb_get_tag (hd, outtag, taglen);
      break;

    default:
      log_error ("gcry_cipher_gettag: invalid mode %d\n", hd->mode);
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;
    }

  return rc;
}


gcry_err_code_t
_gcry_cipher_checktag (gcry_cipher_hd_t hd, const void *intag, size_t taglen)
{
  gcry_err_code_t rc;

  switch (hd->mode)
    {
    case GCRY_CIPHER_MODE_CCM:
      rc = _gcry_cipher_ccm_check_tag (hd, intag, taglen);
      break;

    case GCRY_CIPHER_MODE_CMAC:
      rc = _gcry_cipher_cmac_check_tag (hd, intag, taglen);
      break;

    case GCRY_CIPHER_MODE_GCM:
      rc = _gcry_cipher_gcm_check_tag (hd, intag, taglen);
      break;

    case GCRY_CIPHER_MODE_POLY1305:
      rc = _gcry_cipher_poly1305_check_tag (hd, intag, taglen);
      break;

    case GCRY_CIPHER_MODE_OCB:
      rc = _gcry_cipher_ocb_check_tag (hd, intag, taglen);
      break;

    default:
      log_error ("gcry_cipher_checktag: invalid mode %d\n", hd->mode);
      rc = GPG_ERR_INV_CIPHER_MODE;
      break;
    }

  return rc;
}


gcry_err_code_t
_gcry_cipher_ctl (gcry_cipher_hd_t h, int cmd, void *buffer, size_t buflen)
{
  gcry_err_code_t rc = 0;

  switch (cmd)
    {
    case GCRYCTL_RESET:
      cipher_reset (h);
      break;

    case GCRYCTL_FINALIZE:
      if (!h || buffer || buflen)
	return GPG_ERR_INV_ARG;
      h->marks.finalize = 1;
      break;

    case GCRYCTL_CFB_SYNC:
      cipher_sync( h );
      break;

    case GCRYCTL_SET_CBC_CTS:
      if (buflen)
	if (h->flags & GCRY_CIPHER_CBC_MAC)
	  rc = GPG_ERR_INV_FLAG;
	else
	  h->flags |= GCRY_CIPHER_CBC_CTS;
      else
	h->flags &= ~GCRY_CIPHER_CBC_CTS;
      break;

    case GCRYCTL_SET_CBC_MAC:
      if (buflen)
	if (h->flags & GCRY_CIPHER_CBC_CTS)
	  rc = GPG_ERR_INV_FLAG;
	else
	  h->flags |= GCRY_CIPHER_CBC_MAC;
      else
	h->flags &= ~GCRY_CIPHER_CBC_MAC;
      break;

    case GCRYCTL_SET_CCM_LENGTHS:
      {
        u64 params[3];
        size_t encryptedlen;
        size_t aadlen;
        size_t authtaglen;

        if (h->mode != GCRY_CIPHER_MODE_CCM)
          return GPG_ERR_INV_CIPHER_MODE;

        if (!buffer || buflen != 3 * sizeof(u64))
          return GPG_ERR_INV_ARG;

        /* This command is used to pass additional length parameters needed
           by CCM mode to initialize CBC-MAC.  */
        memcpy (params, buffer, sizeof(params));
        encryptedlen = params[0];
        aadlen = params[1];
        authtaglen = params[2];

        rc = _gcry_cipher_ccm_set_lengths (h, encryptedlen, aadlen, authtaglen);
      }
      break;

    case GCRYCTL_SET_TAGLEN:
      if (!h || !buffer || buflen != sizeof(int) )
	return GPG_ERR_INV_ARG;
      switch (h->mode)
        {
        case GCRY_CIPHER_MODE_OCB:
          switch (*(int*)buffer)
            {
            case 8: case 12: case 16:
              h->u_mode.ocb.taglen = *(int*)buffer;
              break;
            default:
              rc = GPG_ERR_INV_LENGTH; /* Invalid tag length. */
              break;
            }
          break;

        default:
          rc =GPG_ERR_INV_CIPHER_MODE;
          break;
        }
      break;

    case GCRYCTL_DISABLE_ALGO:
      /* This command expects NULL for H and BUFFER to point to an
         integer with the algo number.  */
      if( h || !buffer || buflen != sizeof(int) )
	return GPG_ERR_CIPHER_ALGO;
      disable_cipher_algo( *(int*)buffer );
      break;

    case PRIV_CIPHERCTL_DISABLE_WEAK_KEY:  /* (private)  */
      if (h->spec->set_extra_info)
        rc = h->spec->set_extra_info
          (&h->context.c, CIPHER_INFO_NO_WEAK_KEY, NULL, 0);
      else
        rc = GPG_ERR_NOT_SUPPORTED;
      break;

    case PRIV_CIPHERCTL_GET_INPUT_VECTOR: /* (private)  */
      /* This is the input block as used in CFB and OFB mode which has
         initially been set as IV.  The returned format is:
           1 byte  Actual length of the block in bytes.
           n byte  The block.
         If the provided buffer is too short, an error is returned. */
      if (buflen < (1 + h->spec->blocksize))
        rc = GPG_ERR_TOO_SHORT;
      else
        {
          unsigned char *ivp;
          unsigned char *dst = buffer;
          int n = h->unused;

          if (!n)
            n = h->spec->blocksize;
          gcry_assert (n <= h->spec->blocksize);
          *dst++ = n;
          ivp = h->u_iv.iv + h->spec->blocksize - n;
          while (n--)
            *dst++ = *ivp++;
        }
      break;

    case GCRYCTL_SET_SBOX:
      if (h->spec->set_extra_info)
        rc = h->spec->set_extra_info
          (&h->context.c, GCRYCTL_SET_SBOX, buffer, buflen);
      else
        rc = GPG_ERR_NOT_SUPPORTED;
      break;

    default:
      rc = GPG_ERR_INV_OP;
    }

  return rc;
}


/* Return information about the cipher handle H.  CMD is the kind of
   information requested.  BUFFER and NBYTES are reserved for now.

   There are no values for CMD yet defined.

   The function always returns GPG_ERR_INV_OP.

 */
gcry_err_code_t
_gcry_cipher_info (gcry_cipher_hd_t h, int cmd, void *buffer, size_t *nbytes)
{
  gcry_err_code_t rc = 0;

  (void)h;
  (void)buffer;
  (void)nbytes;

  switch (cmd)
    {
    default:
      rc = GPG_ERR_INV_OP;
    }

  return rc;
}

/* Return information about the given cipher algorithm ALGO.

   WHAT select the kind of information returned:

    GCRYCTL_GET_KEYLEN:
  	Return the length of the key.  If the algorithm ALGO
  	supports multiple key lengths, the maximum supported key length
  	is returned.  The key length is returned as number of octets.
  	BUFFER and NBYTES must be zero.

    GCRYCTL_GET_BLKLEN:
  	Return the blocklength of the algorithm ALGO counted in octets.
  	BUFFER and NBYTES must be zero.

    GCRYCTL_TEST_ALGO:
  	Returns 0 if the specified algorithm ALGO is available for use.
  	BUFFER and NBYTES must be zero.

   Note: Because this function is in most cases used to return an
   integer value, we can make it easier for the caller to just look at
   the return value.  The caller will in all cases consult the value
   and thereby detecting whether a error occurred or not (i.e. while
   checking the block size)
 */
gcry_err_code_t
_gcry_cipher_algo_info (int algo, int what, void *buffer, size_t *nbytes)
{
  gcry_err_code_t rc = 0;
  unsigned int ui;

  switch (what)
    {
    case GCRYCTL_GET_KEYLEN:
      if (buffer || (! nbytes))
	rc = GPG_ERR_CIPHER_ALGO;
      else
	{
	  ui = cipher_get_keylen (algo);
	  if ((ui > 0) && (ui <= 512))
	    *nbytes = (size_t) ui / 8;
	  else
	    /* The only reason for an error is an invalid algo.  */
	    rc = GPG_ERR_CIPHER_ALGO;
	}
      break;

    case GCRYCTL_GET_BLKLEN:
      if (buffer || (! nbytes))
	rc = GPG_ERR_CIPHER_ALGO;
      else
	{
	  ui = cipher_get_blocksize (algo);
	  if ((ui > 0) && (ui < 10000))
	    *nbytes = ui;
	  else
            {
              /* The only reason is an invalid algo or a strange
                 blocksize.  */
              rc = GPG_ERR_CIPHER_ALGO;
            }
	}
      break;

    case GCRYCTL_TEST_ALGO:
      if (buffer || nbytes)
	rc = GPG_ERR_INV_ARG;
      else
	rc = check_cipher_algo (algo);
      break;

      default:
	rc = GPG_ERR_INV_OP;
    }

  return rc;
}


/* This function returns length of the key for algorithm ALGO.  If the
   algorithm supports multiple key lengths, the maximum supported key
   length is returned.  On error 0 is returned.  The key length is
   returned as number of octets.

   This is a convenience functions which should be preferred over
   gcry_cipher_algo_info because it allows for proper type
   checking.  */
size_t
_gcry_cipher_get_algo_keylen (int algo)
{
  size_t n;

  if (_gcry_cipher_algo_info (algo, GCRYCTL_GET_KEYLEN, NULL, &n))
    n = 0;
  return n;
}


/* This functions returns the blocklength of the algorithm ALGO
   counted in octets.  On error 0 is returned.

   This is a convenience functions which should be preferred over
   gcry_cipher_algo_info because it allows for proper type
   checking.  */
size_t
_gcry_cipher_get_algo_blklen (int algo)
{
  size_t n;

  if (_gcry_cipher_algo_info( algo, GCRYCTL_GET_BLKLEN, NULL, &n))
    n = 0;
  return n;
}


/* Explicitly initialize this module.  */
gcry_err_code_t
_gcry_cipher_init (void)
{
  if (fips_mode())
    {
      /* disable algorithms that are disallowed in fips */
      int idx;
      gcry_cipher_spec_t *spec;

      for (idx = 0; (spec = cipher_list[idx]); idx++)
        if (!spec->flags.fips)
          spec->flags.disabled = 1;
    }

  return 0;
}


/* Run the selftests for cipher algorithm ALGO with optional reporting
   function REPORT.  */
gpg_error_t
_gcry_cipher_selftest (int algo, int extended, selftest_report_func_t report)
{
  gcry_err_code_t ec = 0;
  gcry_cipher_spec_t *spec;

  spec = spec_from_algo (algo);
  if (spec && !spec->flags.disabled && spec->selftest)
    ec = spec->selftest (algo, extended, report);
  else
    {
      ec = GPG_ERR_CIPHER_ALGO;
      if (report)
        report ("cipher", algo, "module",
                (spec && !spec->flags.disabled)?
                "no selftest available" :
                spec? "algorithm disabled" : "algorithm not found");
    }

  return gpg_error (ec);
}