summaryrefslogtreecommitdiffstats
path: root/comm/third_party/libgcrypt/cipher/twofish.c
blob: d19e079046a6a6da391116af0f37e55cc429e079 (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
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
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
/* Twofish for GPG
 * Copyright (C) 1998, 2002, 2003 Free Software Foundation, Inc.
 * Written by Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
 * 256-bit key length added March 20, 1999
 * Some modifications to reduce the text size by Werner Koch, April, 1998
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 ********************************************************************
 *
 * This code is a "clean room" implementation, written from the paper
 * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
 * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
 * through http://www.counterpane.com/twofish.html
 *
 * For background information on multiplication in finite fields, used for
 * the matrix operations in the key schedule, see the book _Contemporary
 * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
 * Third Edition.
 *
 * Only the 128- and 256-bit key sizes are supported.  This code is intended
 * for GNU C on a 32-bit system, but it should work almost anywhere.  Loops
 * are unrolled, precomputation tables are used, etc., for maximum speed at
 * some cost in memory consumption. */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* for memcmp() */

#include "types.h"  /* for byte and u32 typedefs */
#include "g10lib.h"
#include "cipher.h"
#include "bufhelp.h"
#include "cipher-internal.h"
#include "cipher-selftest.h"


#define TWOFISH_BLOCKSIZE 16


/* USE_AMD64_ASM indicates whether to use AMD64 assembly code. */
#undef USE_AMD64_ASM
#if defined(__x86_64__) && (defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS) || \
    defined(HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS))
# define USE_AMD64_ASM 1
#endif

/* USE_ARM_ASM indicates whether to use ARM assembly code. */
#undef USE_ARM_ASM
#if defined(__ARMEL__)
# if defined(HAVE_COMPATIBLE_GCC_ARM_PLATFORM_AS)
#  define USE_ARM_ASM 1
# endif
#endif
# if defined(__AARCH64EL__)
#  ifdef HAVE_COMPATIBLE_GCC_AARCH64_PLATFORM_AS
#   define USE_ARM_ASM 1
#  endif
# endif

/* USE_AVX2 indicates whether to compile with AMD64 AVX2 code. */
#undef USE_AVX2
#if defined(__x86_64__) && (defined(HAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS) || \
    defined(HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS))
# if defined(ENABLE_AVX2_SUPPORT)
#  define USE_AVX2 1
# endif
#endif


/* Prototype for the self-test function. */
static const char *selftest(void);


/* Prototypes for the bulk functions. */
static void _gcry_twofish_ctr_enc (void *context, unsigned char *ctr,
				   void *outbuf_arg, const void *inbuf_arg,
				   size_t nblocks);
static void _gcry_twofish_cbc_dec (void *context, unsigned char *iv,
				   void *outbuf_arg, const void *inbuf_arg,
				   size_t nblocks);
static void _gcry_twofish_cfb_dec (void *context, unsigned char *iv,
				   void *outbuf_arg, const void *inbuf_arg,
				   size_t nblocks);
static size_t _gcry_twofish_ocb_crypt (gcry_cipher_hd_t c, void *outbuf_arg,
				       const void *inbuf_arg, size_t nblocks,
				       int encrypt);
static size_t _gcry_twofish_ocb_auth (gcry_cipher_hd_t c, const void *abuf_arg,
				      size_t nblocks);


/* Structure for an expanded Twofish key.  s contains the key-dependent
 * S-boxes composed with the MDS matrix; w contains the eight "whitening"
 * subkeys, K[0] through K[7].	k holds the remaining, "round" subkeys.  Note
 * that k[i] corresponds to what the Twofish paper calls K[i+8]. */
typedef struct {
   u32 s[4][256], w[8], k[32];

#ifdef USE_AVX2
  int use_avx2;
#endif
} TWOFISH_context;


/* Assembly implementations use SystemV ABI, ABI conversion and additional
 * stack to store XMM6-XMM15 needed on Win64. */
#undef ASM_FUNC_ABI
#if defined(USE_AVX2)
# ifdef HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS
#  define ASM_FUNC_ABI __attribute__((sysv_abi))
# else
#  define ASM_FUNC_ABI
# endif
#endif


/* These two tables are the q0 and q1 permutations, exactly as described in
 * the Twofish paper. */

static const byte q0[256] = {
   0xA9, 0x67, 0xB3, 0xE8, 0x04, 0xFD, 0xA3, 0x76, 0x9A, 0x92, 0x80, 0x78,
   0xE4, 0xDD, 0xD1, 0x38, 0x0D, 0xC6, 0x35, 0x98, 0x18, 0xF7, 0xEC, 0x6C,
   0x43, 0x75, 0x37, 0x26, 0xFA, 0x13, 0x94, 0x48, 0xF2, 0xD0, 0x8B, 0x30,
   0x84, 0x54, 0xDF, 0x23, 0x19, 0x5B, 0x3D, 0x59, 0xF3, 0xAE, 0xA2, 0x82,
   0x63, 0x01, 0x83, 0x2E, 0xD9, 0x51, 0x9B, 0x7C, 0xA6, 0xEB, 0xA5, 0xBE,
   0x16, 0x0C, 0xE3, 0x61, 0xC0, 0x8C, 0x3A, 0xF5, 0x73, 0x2C, 0x25, 0x0B,
   0xBB, 0x4E, 0x89, 0x6B, 0x53, 0x6A, 0xB4, 0xF1, 0xE1, 0xE6, 0xBD, 0x45,
   0xE2, 0xF4, 0xB6, 0x66, 0xCC, 0x95, 0x03, 0x56, 0xD4, 0x1C, 0x1E, 0xD7,
   0xFB, 0xC3, 0x8E, 0xB5, 0xE9, 0xCF, 0xBF, 0xBA, 0xEA, 0x77, 0x39, 0xAF,
   0x33, 0xC9, 0x62, 0x71, 0x81, 0x79, 0x09, 0xAD, 0x24, 0xCD, 0xF9, 0xD8,
   0xE5, 0xC5, 0xB9, 0x4D, 0x44, 0x08, 0x86, 0xE7, 0xA1, 0x1D, 0xAA, 0xED,
   0x06, 0x70, 0xB2, 0xD2, 0x41, 0x7B, 0xA0, 0x11, 0x31, 0xC2, 0x27, 0x90,
   0x20, 0xF6, 0x60, 0xFF, 0x96, 0x5C, 0xB1, 0xAB, 0x9E, 0x9C, 0x52, 0x1B,
   0x5F, 0x93, 0x0A, 0xEF, 0x91, 0x85, 0x49, 0xEE, 0x2D, 0x4F, 0x8F, 0x3B,
   0x47, 0x87, 0x6D, 0x46, 0xD6, 0x3E, 0x69, 0x64, 0x2A, 0xCE, 0xCB, 0x2F,
   0xFC, 0x97, 0x05, 0x7A, 0xAC, 0x7F, 0xD5, 0x1A, 0x4B, 0x0E, 0xA7, 0x5A,
   0x28, 0x14, 0x3F, 0x29, 0x88, 0x3C, 0x4C, 0x02, 0xB8, 0xDA, 0xB0, 0x17,
   0x55, 0x1F, 0x8A, 0x7D, 0x57, 0xC7, 0x8D, 0x74, 0xB7, 0xC4, 0x9F, 0x72,
   0x7E, 0x15, 0x22, 0x12, 0x58, 0x07, 0x99, 0x34, 0x6E, 0x50, 0xDE, 0x68,
   0x65, 0xBC, 0xDB, 0xF8, 0xC8, 0xA8, 0x2B, 0x40, 0xDC, 0xFE, 0x32, 0xA4,
   0xCA, 0x10, 0x21, 0xF0, 0xD3, 0x5D, 0x0F, 0x00, 0x6F, 0x9D, 0x36, 0x42,
   0x4A, 0x5E, 0xC1, 0xE0
};

static const byte q1[256] = {
   0x75, 0xF3, 0xC6, 0xF4, 0xDB, 0x7B, 0xFB, 0xC8, 0x4A, 0xD3, 0xE6, 0x6B,
   0x45, 0x7D, 0xE8, 0x4B, 0xD6, 0x32, 0xD8, 0xFD, 0x37, 0x71, 0xF1, 0xE1,
   0x30, 0x0F, 0xF8, 0x1B, 0x87, 0xFA, 0x06, 0x3F, 0x5E, 0xBA, 0xAE, 0x5B,
   0x8A, 0x00, 0xBC, 0x9D, 0x6D, 0xC1, 0xB1, 0x0E, 0x80, 0x5D, 0xD2, 0xD5,
   0xA0, 0x84, 0x07, 0x14, 0xB5, 0x90, 0x2C, 0xA3, 0xB2, 0x73, 0x4C, 0x54,
   0x92, 0x74, 0x36, 0x51, 0x38, 0xB0, 0xBD, 0x5A, 0xFC, 0x60, 0x62, 0x96,
   0x6C, 0x42, 0xF7, 0x10, 0x7C, 0x28, 0x27, 0x8C, 0x13, 0x95, 0x9C, 0xC7,
   0x24, 0x46, 0x3B, 0x70, 0xCA, 0xE3, 0x85, 0xCB, 0x11, 0xD0, 0x93, 0xB8,
   0xA6, 0x83, 0x20, 0xFF, 0x9F, 0x77, 0xC3, 0xCC, 0x03, 0x6F, 0x08, 0xBF,
   0x40, 0xE7, 0x2B, 0xE2, 0x79, 0x0C, 0xAA, 0x82, 0x41, 0x3A, 0xEA, 0xB9,
   0xE4, 0x9A, 0xA4, 0x97, 0x7E, 0xDA, 0x7A, 0x17, 0x66, 0x94, 0xA1, 0x1D,
   0x3D, 0xF0, 0xDE, 0xB3, 0x0B, 0x72, 0xA7, 0x1C, 0xEF, 0xD1, 0x53, 0x3E,
   0x8F, 0x33, 0x26, 0x5F, 0xEC, 0x76, 0x2A, 0x49, 0x81, 0x88, 0xEE, 0x21,
   0xC4, 0x1A, 0xEB, 0xD9, 0xC5, 0x39, 0x99, 0xCD, 0xAD, 0x31, 0x8B, 0x01,
   0x18, 0x23, 0xDD, 0x1F, 0x4E, 0x2D, 0xF9, 0x48, 0x4F, 0xF2, 0x65, 0x8E,
   0x78, 0x5C, 0x58, 0x19, 0x8D, 0xE5, 0x98, 0x57, 0x67, 0x7F, 0x05, 0x64,
   0xAF, 0x63, 0xB6, 0xFE, 0xF5, 0xB7, 0x3C, 0xA5, 0xCE, 0xE9, 0x68, 0x44,
   0xE0, 0x4D, 0x43, 0x69, 0x29, 0x2E, 0xAC, 0x15, 0x59, 0xA8, 0x0A, 0x9E,
   0x6E, 0x47, 0xDF, 0x34, 0x35, 0x6A, 0xCF, 0xDC, 0x22, 0xC9, 0xC0, 0x9B,
   0x89, 0xD4, 0xED, 0xAB, 0x12, 0xA2, 0x0D, 0x52, 0xBB, 0x02, 0x2F, 0xA9,
   0xD7, 0x61, 0x1E, 0xB4, 0x50, 0x04, 0xF6, 0xC2, 0x16, 0x25, 0x86, 0x56,
   0x55, 0x09, 0xBE, 0x91
};

/* These MDS tables are actually tables of MDS composed with q0 and q1,
 * because it is only ever used that way and we can save some time by
 * precomputing.  Of course the main saving comes from precomputing the
 * GF(2^8) multiplication involved in the MDS matrix multiply; by looking
 * things up in these tables we reduce the matrix multiply to four lookups
 * and three XORs.  Semi-formally, the definition of these tables is:
 * mds[0][i] = MDS (q1[i] 0 0 0)^T  mds[1][i] = MDS (0 q0[i] 0 0)^T
 * mds[2][i] = MDS (0 0 q1[i] 0)^T  mds[3][i] = MDS (0 0 0 q0[i])^T
 * where ^T means "transpose", the matrix multiply is performed in GF(2^8)
 * represented as GF(2)[x]/v(x) where v(x)=x^8+x^6+x^5+x^3+1 as described
 * by Schneier et al, and I'm casually glossing over the byte/word
 * conversion issues. */

static const u32 mds[4][256] = {
   {0xBCBC3275, 0xECEC21F3, 0x202043C6, 0xB3B3C9F4, 0xDADA03DB, 0x02028B7B,
    0xE2E22BFB, 0x9E9EFAC8, 0xC9C9EC4A, 0xD4D409D3, 0x18186BE6, 0x1E1E9F6B,
    0x98980E45, 0xB2B2387D, 0xA6A6D2E8, 0x2626B74B, 0x3C3C57D6, 0x93938A32,
    0x8282EED8, 0x525298FD, 0x7B7BD437, 0xBBBB3771, 0x5B5B97F1, 0x474783E1,
    0x24243C30, 0x5151E20F, 0xBABAC6F8, 0x4A4AF31B, 0xBFBF4887, 0x0D0D70FA,
    0xB0B0B306, 0x7575DE3F, 0xD2D2FD5E, 0x7D7D20BA, 0x666631AE, 0x3A3AA35B,
    0x59591C8A, 0x00000000, 0xCDCD93BC, 0x1A1AE09D, 0xAEAE2C6D, 0x7F7FABC1,
    0x2B2BC7B1, 0xBEBEB90E, 0xE0E0A080, 0x8A8A105D, 0x3B3B52D2, 0x6464BAD5,
    0xD8D888A0, 0xE7E7A584, 0x5F5FE807, 0x1B1B1114, 0x2C2CC2B5, 0xFCFCB490,
    0x3131272C, 0x808065A3, 0x73732AB2, 0x0C0C8173, 0x79795F4C, 0x6B6B4154,
    0x4B4B0292, 0x53536974, 0x94948F36, 0x83831F51, 0x2A2A3638, 0xC4C49CB0,
    0x2222C8BD, 0xD5D5F85A, 0xBDBDC3FC, 0x48487860, 0xFFFFCE62, 0x4C4C0796,
    0x4141776C, 0xC7C7E642, 0xEBEB24F7, 0x1C1C1410, 0x5D5D637C, 0x36362228,
    0x6767C027, 0xE9E9AF8C, 0x4444F913, 0x1414EA95, 0xF5F5BB9C, 0xCFCF18C7,
    0x3F3F2D24, 0xC0C0E346, 0x7272DB3B, 0x54546C70, 0x29294CCA, 0xF0F035E3,
    0x0808FE85, 0xC6C617CB, 0xF3F34F11, 0x8C8CE4D0, 0xA4A45993, 0xCACA96B8,
    0x68683BA6, 0xB8B84D83, 0x38382820, 0xE5E52EFF, 0xADAD569F, 0x0B0B8477,
    0xC8C81DC3, 0x9999FFCC, 0x5858ED03, 0x19199A6F, 0x0E0E0A08, 0x95957EBF,
    0x70705040, 0xF7F730E7, 0x6E6ECF2B, 0x1F1F6EE2, 0xB5B53D79, 0x09090F0C,
    0x616134AA, 0x57571682, 0x9F9F0B41, 0x9D9D803A, 0x111164EA, 0x2525CDB9,
    0xAFAFDDE4, 0x4545089A, 0xDFDF8DA4, 0xA3A35C97, 0xEAEAD57E, 0x353558DA,
    0xEDEDD07A, 0x4343FC17, 0xF8F8CB66, 0xFBFBB194, 0x3737D3A1, 0xFAFA401D,
    0xC2C2683D, 0xB4B4CCF0, 0x32325DDE, 0x9C9C71B3, 0x5656E70B, 0xE3E3DA72,
    0x878760A7, 0x15151B1C, 0xF9F93AEF, 0x6363BFD1, 0x3434A953, 0x9A9A853E,
    0xB1B1428F, 0x7C7CD133, 0x88889B26, 0x3D3DA65F, 0xA1A1D7EC, 0xE4E4DF76,
    0x8181942A, 0x91910149, 0x0F0FFB81, 0xEEEEAA88, 0x161661EE, 0xD7D77321,
    0x9797F5C4, 0xA5A5A81A, 0xFEFE3FEB, 0x6D6DB5D9, 0x7878AEC5, 0xC5C56D39,
    0x1D1DE599, 0x7676A4CD, 0x3E3EDCAD, 0xCBCB6731, 0xB6B6478B, 0xEFEF5B01,
    0x12121E18, 0x6060C523, 0x6A6AB0DD, 0x4D4DF61F, 0xCECEE94E, 0xDEDE7C2D,
    0x55559DF9, 0x7E7E5A48, 0x2121B24F, 0x03037AF2, 0xA0A02665, 0x5E5E198E,
    0x5A5A6678, 0x65654B5C, 0x62624E58, 0xFDFD4519, 0x0606F48D, 0x404086E5,
    0xF2F2BE98, 0x3333AC57, 0x17179067, 0x05058E7F, 0xE8E85E05, 0x4F4F7D64,
    0x89896AAF, 0x10109563, 0x74742FB6, 0x0A0A75FE, 0x5C5C92F5, 0x9B9B74B7,
    0x2D2D333C, 0x3030D6A5, 0x2E2E49CE, 0x494989E9, 0x46467268, 0x77775544,
    0xA8A8D8E0, 0x9696044D, 0x2828BD43, 0xA9A92969, 0xD9D97929, 0x8686912E,
    0xD1D187AC, 0xF4F44A15, 0x8D8D1559, 0xD6D682A8, 0xB9B9BC0A, 0x42420D9E,
    0xF6F6C16E, 0x2F2FB847, 0xDDDD06DF, 0x23233934, 0xCCCC6235, 0xF1F1C46A,
    0xC1C112CF, 0x8585EBDC, 0x8F8F9E22, 0x7171A1C9, 0x9090F0C0, 0xAAAA539B,
    0x0101F189, 0x8B8BE1D4, 0x4E4E8CED, 0x8E8E6FAB, 0xABABA212, 0x6F6F3EA2,
    0xE6E6540D, 0xDBDBF252, 0x92927BBB, 0xB7B7B602, 0x6969CA2F, 0x3939D9A9,
    0xD3D30CD7, 0xA7A72361, 0xA2A2AD1E, 0xC3C399B4, 0x6C6C4450, 0x07070504,
    0x04047FF6, 0x272746C2, 0xACACA716, 0xD0D07625, 0x50501386, 0xDCDCF756,
    0x84841A55, 0xE1E15109, 0x7A7A25BE, 0x1313EF91},

   {0xA9D93939, 0x67901717, 0xB3719C9C, 0xE8D2A6A6, 0x04050707, 0xFD985252,
    0xA3658080, 0x76DFE4E4, 0x9A084545, 0x92024B4B, 0x80A0E0E0, 0x78665A5A,
    0xE4DDAFAF, 0xDDB06A6A, 0xD1BF6363, 0x38362A2A, 0x0D54E6E6, 0xC6432020,
    0x3562CCCC, 0x98BEF2F2, 0x181E1212, 0xF724EBEB, 0xECD7A1A1, 0x6C774141,
    0x43BD2828, 0x7532BCBC, 0x37D47B7B, 0x269B8888, 0xFA700D0D, 0x13F94444,
    0x94B1FBFB, 0x485A7E7E, 0xF27A0303, 0xD0E48C8C, 0x8B47B6B6, 0x303C2424,
    0x84A5E7E7, 0x54416B6B, 0xDF06DDDD, 0x23C56060, 0x1945FDFD, 0x5BA33A3A,
    0x3D68C2C2, 0x59158D8D, 0xF321ECEC, 0xAE316666, 0xA23E6F6F, 0x82165757,
    0x63951010, 0x015BEFEF, 0x834DB8B8, 0x2E918686, 0xD9B56D6D, 0x511F8383,
    0x9B53AAAA, 0x7C635D5D, 0xA63B6868, 0xEB3FFEFE, 0xA5D63030, 0xBE257A7A,
    0x16A7ACAC, 0x0C0F0909, 0xE335F0F0, 0x6123A7A7, 0xC0F09090, 0x8CAFE9E9,
    0x3A809D9D, 0xF5925C5C, 0x73810C0C, 0x2C273131, 0x2576D0D0, 0x0BE75656,
    0xBB7B9292, 0x4EE9CECE, 0x89F10101, 0x6B9F1E1E, 0x53A93434, 0x6AC4F1F1,
    0xB499C3C3, 0xF1975B5B, 0xE1834747, 0xE66B1818, 0xBDC82222, 0x450E9898,
    0xE26E1F1F, 0xF4C9B3B3, 0xB62F7474, 0x66CBF8F8, 0xCCFF9999, 0x95EA1414,
    0x03ED5858, 0x56F7DCDC, 0xD4E18B8B, 0x1C1B1515, 0x1EADA2A2, 0xD70CD3D3,
    0xFB2BE2E2, 0xC31DC8C8, 0x8E195E5E, 0xB5C22C2C, 0xE9894949, 0xCF12C1C1,
    0xBF7E9595, 0xBA207D7D, 0xEA641111, 0x77840B0B, 0x396DC5C5, 0xAF6A8989,
    0x33D17C7C, 0xC9A17171, 0x62CEFFFF, 0x7137BBBB, 0x81FB0F0F, 0x793DB5B5,
    0x0951E1E1, 0xADDC3E3E, 0x242D3F3F, 0xCDA47676, 0xF99D5555, 0xD8EE8282,
    0xE5864040, 0xC5AE7878, 0xB9CD2525, 0x4D049696, 0x44557777, 0x080A0E0E,
    0x86135050, 0xE730F7F7, 0xA1D33737, 0x1D40FAFA, 0xAA346161, 0xED8C4E4E,
    0x06B3B0B0, 0x706C5454, 0xB22A7373, 0xD2523B3B, 0x410B9F9F, 0x7B8B0202,
    0xA088D8D8, 0x114FF3F3, 0x3167CBCB, 0xC2462727, 0x27C06767, 0x90B4FCFC,
    0x20283838, 0xF67F0404, 0x60784848, 0xFF2EE5E5, 0x96074C4C, 0x5C4B6565,
    0xB1C72B2B, 0xAB6F8E8E, 0x9E0D4242, 0x9CBBF5F5, 0x52F2DBDB, 0x1BF34A4A,
    0x5FA63D3D, 0x9359A4A4, 0x0ABCB9B9, 0xEF3AF9F9, 0x91EF1313, 0x85FE0808,
    0x49019191, 0xEE611616, 0x2D7CDEDE, 0x4FB22121, 0x8F42B1B1, 0x3BDB7272,
    0x47B82F2F, 0x8748BFBF, 0x6D2CAEAE, 0x46E3C0C0, 0xD6573C3C, 0x3E859A9A,
    0x6929A9A9, 0x647D4F4F, 0x2A948181, 0xCE492E2E, 0xCB17C6C6, 0x2FCA6969,
    0xFCC3BDBD, 0x975CA3A3, 0x055EE8E8, 0x7AD0EDED, 0xAC87D1D1, 0x7F8E0505,
    0xD5BA6464, 0x1AA8A5A5, 0x4BB72626, 0x0EB9BEBE, 0xA7608787, 0x5AF8D5D5,
    0x28223636, 0x14111B1B, 0x3FDE7575, 0x2979D9D9, 0x88AAEEEE, 0x3C332D2D,
    0x4C5F7979, 0x02B6B7B7, 0xB896CACA, 0xDA583535, 0xB09CC4C4, 0x17FC4343,
    0x551A8484, 0x1FF64D4D, 0x8A1C5959, 0x7D38B2B2, 0x57AC3333, 0xC718CFCF,
    0x8DF40606, 0x74695353, 0xB7749B9B, 0xC4F59797, 0x9F56ADAD, 0x72DAE3E3,
    0x7ED5EAEA, 0x154AF4F4, 0x229E8F8F, 0x12A2ABAB, 0x584E6262, 0x07E85F5F,
    0x99E51D1D, 0x34392323, 0x6EC1F6F6, 0x50446C6C, 0xDE5D3232, 0x68724646,
    0x6526A0A0, 0xBC93CDCD, 0xDB03DADA, 0xF8C6BABA, 0xC8FA9E9E, 0xA882D6D6,
    0x2BCF6E6E, 0x40507070, 0xDCEB8585, 0xFE750A0A, 0x328A9393, 0xA48DDFDF,
    0xCA4C2929, 0x10141C1C, 0x2173D7D7, 0xF0CCB4B4, 0xD309D4D4, 0x5D108A8A,
    0x0FE25151, 0x00000000, 0x6F9A1919, 0x9DE01A1A, 0x368F9494, 0x42E6C7C7,
    0x4AECC9C9, 0x5EFDD2D2, 0xC1AB7F7F, 0xE0D8A8A8},

   {0xBC75BC32, 0xECF3EC21, 0x20C62043, 0xB3F4B3C9, 0xDADBDA03, 0x027B028B,
    0xE2FBE22B, 0x9EC89EFA, 0xC94AC9EC, 0xD4D3D409, 0x18E6186B, 0x1E6B1E9F,
    0x9845980E, 0xB27DB238, 0xA6E8A6D2, 0x264B26B7, 0x3CD63C57, 0x9332938A,
    0x82D882EE, 0x52FD5298, 0x7B377BD4, 0xBB71BB37, 0x5BF15B97, 0x47E14783,
    0x2430243C, 0x510F51E2, 0xBAF8BAC6, 0x4A1B4AF3, 0xBF87BF48, 0x0DFA0D70,
    0xB006B0B3, 0x753F75DE, 0xD25ED2FD, 0x7DBA7D20, 0x66AE6631, 0x3A5B3AA3,
    0x598A591C, 0x00000000, 0xCDBCCD93, 0x1A9D1AE0, 0xAE6DAE2C, 0x7FC17FAB,
    0x2BB12BC7, 0xBE0EBEB9, 0xE080E0A0, 0x8A5D8A10, 0x3BD23B52, 0x64D564BA,
    0xD8A0D888, 0xE784E7A5, 0x5F075FE8, 0x1B141B11, 0x2CB52CC2, 0xFC90FCB4,
    0x312C3127, 0x80A38065, 0x73B2732A, 0x0C730C81, 0x794C795F, 0x6B546B41,
    0x4B924B02, 0x53745369, 0x9436948F, 0x8351831F, 0x2A382A36, 0xC4B0C49C,
    0x22BD22C8, 0xD55AD5F8, 0xBDFCBDC3, 0x48604878, 0xFF62FFCE, 0x4C964C07,
    0x416C4177, 0xC742C7E6, 0xEBF7EB24, 0x1C101C14, 0x5D7C5D63, 0x36283622,
    0x672767C0, 0xE98CE9AF, 0x441344F9, 0x149514EA, 0xF59CF5BB, 0xCFC7CF18,
    0x3F243F2D, 0xC046C0E3, 0x723B72DB, 0x5470546C, 0x29CA294C, 0xF0E3F035,
    0x088508FE, 0xC6CBC617, 0xF311F34F, 0x8CD08CE4, 0xA493A459, 0xCAB8CA96,
    0x68A6683B, 0xB883B84D, 0x38203828, 0xE5FFE52E, 0xAD9FAD56, 0x0B770B84,
    0xC8C3C81D, 0x99CC99FF, 0x580358ED, 0x196F199A, 0x0E080E0A, 0x95BF957E,
    0x70407050, 0xF7E7F730, 0x6E2B6ECF, 0x1FE21F6E, 0xB579B53D, 0x090C090F,
    0x61AA6134, 0x57825716, 0x9F419F0B, 0x9D3A9D80, 0x11EA1164, 0x25B925CD,
    0xAFE4AFDD, 0x459A4508, 0xDFA4DF8D, 0xA397A35C, 0xEA7EEAD5, 0x35DA3558,
    0xED7AEDD0, 0x431743FC, 0xF866F8CB, 0xFB94FBB1, 0x37A137D3, 0xFA1DFA40,
    0xC23DC268, 0xB4F0B4CC, 0x32DE325D, 0x9CB39C71, 0x560B56E7, 0xE372E3DA,
    0x87A78760, 0x151C151B, 0xF9EFF93A, 0x63D163BF, 0x345334A9, 0x9A3E9A85,
    0xB18FB142, 0x7C337CD1, 0x8826889B, 0x3D5F3DA6, 0xA1ECA1D7, 0xE476E4DF,
    0x812A8194, 0x91499101, 0x0F810FFB, 0xEE88EEAA, 0x16EE1661, 0xD721D773,
    0x97C497F5, 0xA51AA5A8, 0xFEEBFE3F, 0x6DD96DB5, 0x78C578AE, 0xC539C56D,
    0x1D991DE5, 0x76CD76A4, 0x3EAD3EDC, 0xCB31CB67, 0xB68BB647, 0xEF01EF5B,
    0x1218121E, 0x602360C5, 0x6ADD6AB0, 0x4D1F4DF6, 0xCE4ECEE9, 0xDE2DDE7C,
    0x55F9559D, 0x7E487E5A, 0x214F21B2, 0x03F2037A, 0xA065A026, 0x5E8E5E19,
    0x5A785A66, 0x655C654B, 0x6258624E, 0xFD19FD45, 0x068D06F4, 0x40E54086,
    0xF298F2BE, 0x335733AC, 0x17671790, 0x057F058E, 0xE805E85E, 0x4F644F7D,
    0x89AF896A, 0x10631095, 0x74B6742F, 0x0AFE0A75, 0x5CF55C92, 0x9BB79B74,
    0x2D3C2D33, 0x30A530D6, 0x2ECE2E49, 0x49E94989, 0x46684672, 0x77447755,
    0xA8E0A8D8, 0x964D9604, 0x284328BD, 0xA969A929, 0xD929D979, 0x862E8691,
    0xD1ACD187, 0xF415F44A, 0x8D598D15, 0xD6A8D682, 0xB90AB9BC, 0x429E420D,
    0xF66EF6C1, 0x2F472FB8, 0xDDDFDD06, 0x23342339, 0xCC35CC62, 0xF16AF1C4,
    0xC1CFC112, 0x85DC85EB, 0x8F228F9E, 0x71C971A1, 0x90C090F0, 0xAA9BAA53,
    0x018901F1, 0x8BD48BE1, 0x4EED4E8C, 0x8EAB8E6F, 0xAB12ABA2, 0x6FA26F3E,
    0xE60DE654, 0xDB52DBF2, 0x92BB927B, 0xB702B7B6, 0x692F69CA, 0x39A939D9,
    0xD3D7D30C, 0xA761A723, 0xA21EA2AD, 0xC3B4C399, 0x6C506C44, 0x07040705,
    0x04F6047F, 0x27C22746, 0xAC16ACA7, 0xD025D076, 0x50865013, 0xDC56DCF7,
    0x8455841A, 0xE109E151, 0x7ABE7A25, 0x139113EF},

   {0xD939A9D9, 0x90176790, 0x719CB371, 0xD2A6E8D2, 0x05070405, 0x9852FD98,
    0x6580A365, 0xDFE476DF, 0x08459A08, 0x024B9202, 0xA0E080A0, 0x665A7866,
    0xDDAFE4DD, 0xB06ADDB0, 0xBF63D1BF, 0x362A3836, 0x54E60D54, 0x4320C643,
    0x62CC3562, 0xBEF298BE, 0x1E12181E, 0x24EBF724, 0xD7A1ECD7, 0x77416C77,
    0xBD2843BD, 0x32BC7532, 0xD47B37D4, 0x9B88269B, 0x700DFA70, 0xF94413F9,
    0xB1FB94B1, 0x5A7E485A, 0x7A03F27A, 0xE48CD0E4, 0x47B68B47, 0x3C24303C,
    0xA5E784A5, 0x416B5441, 0x06DDDF06, 0xC56023C5, 0x45FD1945, 0xA33A5BA3,
    0x68C23D68, 0x158D5915, 0x21ECF321, 0x3166AE31, 0x3E6FA23E, 0x16578216,
    0x95106395, 0x5BEF015B, 0x4DB8834D, 0x91862E91, 0xB56DD9B5, 0x1F83511F,
    0x53AA9B53, 0x635D7C63, 0x3B68A63B, 0x3FFEEB3F, 0xD630A5D6, 0x257ABE25,
    0xA7AC16A7, 0x0F090C0F, 0x35F0E335, 0x23A76123, 0xF090C0F0, 0xAFE98CAF,
    0x809D3A80, 0x925CF592, 0x810C7381, 0x27312C27, 0x76D02576, 0xE7560BE7,
    0x7B92BB7B, 0xE9CE4EE9, 0xF10189F1, 0x9F1E6B9F, 0xA93453A9, 0xC4F16AC4,
    0x99C3B499, 0x975BF197, 0x8347E183, 0x6B18E66B, 0xC822BDC8, 0x0E98450E,
    0x6E1FE26E, 0xC9B3F4C9, 0x2F74B62F, 0xCBF866CB, 0xFF99CCFF, 0xEA1495EA,
    0xED5803ED, 0xF7DC56F7, 0xE18BD4E1, 0x1B151C1B, 0xADA21EAD, 0x0CD3D70C,
    0x2BE2FB2B, 0x1DC8C31D, 0x195E8E19, 0xC22CB5C2, 0x8949E989, 0x12C1CF12,
    0x7E95BF7E, 0x207DBA20, 0x6411EA64, 0x840B7784, 0x6DC5396D, 0x6A89AF6A,
    0xD17C33D1, 0xA171C9A1, 0xCEFF62CE, 0x37BB7137, 0xFB0F81FB, 0x3DB5793D,
    0x51E10951, 0xDC3EADDC, 0x2D3F242D, 0xA476CDA4, 0x9D55F99D, 0xEE82D8EE,
    0x8640E586, 0xAE78C5AE, 0xCD25B9CD, 0x04964D04, 0x55774455, 0x0A0E080A,
    0x13508613, 0x30F7E730, 0xD337A1D3, 0x40FA1D40, 0x3461AA34, 0x8C4EED8C,
    0xB3B006B3, 0x6C54706C, 0x2A73B22A, 0x523BD252, 0x0B9F410B, 0x8B027B8B,
    0x88D8A088, 0x4FF3114F, 0x67CB3167, 0x4627C246, 0xC06727C0, 0xB4FC90B4,
    0x28382028, 0x7F04F67F, 0x78486078, 0x2EE5FF2E, 0x074C9607, 0x4B655C4B,
    0xC72BB1C7, 0x6F8EAB6F, 0x0D429E0D, 0xBBF59CBB, 0xF2DB52F2, 0xF34A1BF3,
    0xA63D5FA6, 0x59A49359, 0xBCB90ABC, 0x3AF9EF3A, 0xEF1391EF, 0xFE0885FE,
    0x01914901, 0x6116EE61, 0x7CDE2D7C, 0xB2214FB2, 0x42B18F42, 0xDB723BDB,
    0xB82F47B8, 0x48BF8748, 0x2CAE6D2C, 0xE3C046E3, 0x573CD657, 0x859A3E85,
    0x29A96929, 0x7D4F647D, 0x94812A94, 0x492ECE49, 0x17C6CB17, 0xCA692FCA,
    0xC3BDFCC3, 0x5CA3975C, 0x5EE8055E, 0xD0ED7AD0, 0x87D1AC87, 0x8E057F8E,
    0xBA64D5BA, 0xA8A51AA8, 0xB7264BB7, 0xB9BE0EB9, 0x6087A760, 0xF8D55AF8,
    0x22362822, 0x111B1411, 0xDE753FDE, 0x79D92979, 0xAAEE88AA, 0x332D3C33,
    0x5F794C5F, 0xB6B702B6, 0x96CAB896, 0x5835DA58, 0x9CC4B09C, 0xFC4317FC,
    0x1A84551A, 0xF64D1FF6, 0x1C598A1C, 0x38B27D38, 0xAC3357AC, 0x18CFC718,
    0xF4068DF4, 0x69537469, 0x749BB774, 0xF597C4F5, 0x56AD9F56, 0xDAE372DA,
    0xD5EA7ED5, 0x4AF4154A, 0x9E8F229E, 0xA2AB12A2, 0x4E62584E, 0xE85F07E8,
    0xE51D99E5, 0x39233439, 0xC1F66EC1, 0x446C5044, 0x5D32DE5D, 0x72466872,
    0x26A06526, 0x93CDBC93, 0x03DADB03, 0xC6BAF8C6, 0xFA9EC8FA, 0x82D6A882,
    0xCF6E2BCF, 0x50704050, 0xEB85DCEB, 0x750AFE75, 0x8A93328A, 0x8DDFA48D,
    0x4C29CA4C, 0x141C1014, 0x73D72173, 0xCCB4F0CC, 0x09D4D309, 0x108A5D10,
    0xE2510FE2, 0x00000000, 0x9A196F9A, 0xE01A9DE0, 0x8F94368F, 0xE6C742E6,
    0xECC94AEC, 0xFDD25EFD, 0xAB7FC1AB, 0xD8A8E0D8}
};

/* The exp_to_poly and poly_to_exp tables are used to perform efficient
 * operations in GF(2^8) represented as GF(2)[x]/w(x) where
 * w(x)=x^8+x^6+x^3+x^2+1.  We care about doing that because it's part of the
 * definition of the RS matrix in the key schedule.  Elements of that field
 * are polynomials of degree not greater than 7 and all coefficients 0 or 1,
 * which can be represented naturally by bytes (just substitute x=2).  In that
 * form, GF(2^8) addition is the same as bitwise XOR, but GF(2^8)
 * multiplication is inefficient without hardware support.  To multiply
 * faster, I make use of the fact x is a generator for the nonzero elements,
 * so that every element p of GF(2)[x]/w(x) is either 0 or equal to (x)^n for
 * some n in 0..254.  Note that that caret is exponentiation in GF(2^8),
 * *not* polynomial notation.  So if I want to compute pq where p and q are
 * in GF(2^8), I can just say:
 *    1. if p=0 or q=0 then pq=0
 *    2. otherwise, find m and n such that p=x^m and q=x^n
 *    3. pq=(x^m)(x^n)=x^(m+n), so add m and n and find pq
 * The translations in steps 2 and 3 are looked up in the tables
 * poly_to_exp (for step 2) and exp_to_poly (for step 3).  To see this
 * in action, look at the CALC_S macro.  As additional wrinkles, note that
 * one of my operands is always a constant, so the poly_to_exp lookup on it
 * is done in advance; I included the original values in the comments so
 * readers can have some chance of recognizing that this *is* the RS matrix
 * from the Twofish paper.  I've only included the table entries I actually
 * need; I never do a lookup on a variable input of zero and the biggest
 * exponents I'll ever see are 254 (variable) and 237 (constant), so they'll
 * never sum to more than 491.	I'm repeating part of the exp_to_poly table
 * so that I don't have to do mod-255 reduction in the exponent arithmetic.
 * Since I know my constant operands are never zero, I only have to worry
 * about zero values in the variable operand, and I do it with a simple
 * conditional branch.	I know conditionals are expensive, but I couldn't
 * see a non-horrible way of avoiding them, and I did manage to group the
 * statements so that each if covers four group multiplications. */

static const u16 poly_to_exp[256] = {
   492,
   0x00, 0x01, 0x17, 0x02, 0x2E, 0x18, 0x53, 0x03, 0x6A, 0x2F, 0x93, 0x19,
   0x34, 0x54, 0x45, 0x04, 0x5C, 0x6B, 0xB6, 0x30, 0xA6, 0x94, 0x4B, 0x1A,
   0x8C, 0x35, 0x81, 0x55, 0xAA, 0x46, 0x0D, 0x05, 0x24, 0x5D, 0x87, 0x6C,
   0x9B, 0xB7, 0xC1, 0x31, 0x2B, 0xA7, 0xA3, 0x95, 0x98, 0x4C, 0xCA, 0x1B,
   0xE6, 0x8D, 0x73, 0x36, 0xCD, 0x82, 0x12, 0x56, 0x62, 0xAB, 0xF0, 0x47,
   0x4F, 0x0E, 0xBD, 0x06, 0xD4, 0x25, 0xD2, 0x5E, 0x27, 0x88, 0x66, 0x6D,
   0xD6, 0x9C, 0x79, 0xB8, 0x08, 0xC2, 0xDF, 0x32, 0x68, 0x2C, 0xFD, 0xA8,
   0x8A, 0xA4, 0x5A, 0x96, 0x29, 0x99, 0x22, 0x4D, 0x60, 0xCB, 0xE4, 0x1C,
   0x7B, 0xE7, 0x3B, 0x8E, 0x9E, 0x74, 0xF4, 0x37, 0xD8, 0xCE, 0xF9, 0x83,
   0x6F, 0x13, 0xB2, 0x57, 0xE1, 0x63, 0xDC, 0xAC, 0xC4, 0xF1, 0xAF, 0x48,
   0x0A, 0x50, 0x42, 0x0F, 0xBA, 0xBE, 0xC7, 0x07, 0xDE, 0xD5, 0x78, 0x26,
   0x65, 0xD3, 0xD1, 0x5F, 0xE3, 0x28, 0x21, 0x89, 0x59, 0x67, 0xFC, 0x6E,
   0xB1, 0xD7, 0xF8, 0x9D, 0xF3, 0x7A, 0x3A, 0xB9, 0xC6, 0x09, 0x41, 0xC3,
   0xAE, 0xE0, 0xDB, 0x33, 0x44, 0x69, 0x92, 0x2D, 0x52, 0xFE, 0x16, 0xA9,
   0x0C, 0x8B, 0x80, 0xA5, 0x4A, 0x5B, 0xB5, 0x97, 0xC9, 0x2A, 0xA2, 0x9A,
   0xC0, 0x23, 0x86, 0x4E, 0xBC, 0x61, 0xEF, 0xCC, 0x11, 0xE5, 0x72, 0x1D,
   0x3D, 0x7C, 0xEB, 0xE8, 0xE9, 0x3C, 0xEA, 0x8F, 0x7D, 0x9F, 0xEC, 0x75,
   0x1E, 0xF5, 0x3E, 0x38, 0xF6, 0xD9, 0x3F, 0xCF, 0x76, 0xFA, 0x1F, 0x84,
   0xA0, 0x70, 0xED, 0x14, 0x90, 0xB3, 0x7E, 0x58, 0xFB, 0xE2, 0x20, 0x64,
   0xD0, 0xDD, 0x77, 0xAD, 0xDA, 0xC5, 0x40, 0xF2, 0x39, 0xB0, 0xF7, 0x49,
   0xB4, 0x0B, 0x7F, 0x51, 0x15, 0x43, 0x91, 0x10, 0x71, 0xBB, 0xEE, 0xBF,
   0x85, 0xC8, 0xA1
};

static const byte exp_to_poly[492 + 256] = {
   0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x4D, 0x9A, 0x79, 0xF2,
   0xA9, 0x1F, 0x3E, 0x7C, 0xF8, 0xBD, 0x37, 0x6E, 0xDC, 0xF5, 0xA7, 0x03,
   0x06, 0x0C, 0x18, 0x30, 0x60, 0xC0, 0xCD, 0xD7, 0xE3, 0x8B, 0x5B, 0xB6,
   0x21, 0x42, 0x84, 0x45, 0x8A, 0x59, 0xB2, 0x29, 0x52, 0xA4, 0x05, 0x0A,
   0x14, 0x28, 0x50, 0xA0, 0x0D, 0x1A, 0x34, 0x68, 0xD0, 0xED, 0x97, 0x63,
   0xC6, 0xC1, 0xCF, 0xD3, 0xEB, 0x9B, 0x7B, 0xF6, 0xA1, 0x0F, 0x1E, 0x3C,
   0x78, 0xF0, 0xAD, 0x17, 0x2E, 0x5C, 0xB8, 0x3D, 0x7A, 0xF4, 0xA5, 0x07,
   0x0E, 0x1C, 0x38, 0x70, 0xE0, 0x8D, 0x57, 0xAE, 0x11, 0x22, 0x44, 0x88,
   0x5D, 0xBA, 0x39, 0x72, 0xE4, 0x85, 0x47, 0x8E, 0x51, 0xA2, 0x09, 0x12,
   0x24, 0x48, 0x90, 0x6D, 0xDA, 0xF9, 0xBF, 0x33, 0x66, 0xCC, 0xD5, 0xE7,
   0x83, 0x4B, 0x96, 0x61, 0xC2, 0xC9, 0xDF, 0xF3, 0xAB, 0x1B, 0x36, 0x6C,
   0xD8, 0xFD, 0xB7, 0x23, 0x46, 0x8C, 0x55, 0xAA, 0x19, 0x32, 0x64, 0xC8,
   0xDD, 0xF7, 0xA3, 0x0B, 0x16, 0x2C, 0x58, 0xB0, 0x2D, 0x5A, 0xB4, 0x25,
   0x4A, 0x94, 0x65, 0xCA, 0xD9, 0xFF, 0xB3, 0x2B, 0x56, 0xAC, 0x15, 0x2A,
   0x54, 0xA8, 0x1D, 0x3A, 0x74, 0xE8, 0x9D, 0x77, 0xEE, 0x91, 0x6F, 0xDE,
   0xF1, 0xAF, 0x13, 0x26, 0x4C, 0x98, 0x7D, 0xFA, 0xB9, 0x3F, 0x7E, 0xFC,
   0xB5, 0x27, 0x4E, 0x9C, 0x75, 0xEA, 0x99, 0x7F, 0xFE, 0xB1, 0x2F, 0x5E,
   0xBC, 0x35, 0x6A, 0xD4, 0xE5, 0x87, 0x43, 0x86, 0x41, 0x82, 0x49, 0x92,
   0x69, 0xD2, 0xE9, 0x9F, 0x73, 0xE6, 0x81, 0x4F, 0x9E, 0x71, 0xE2, 0x89,
   0x5F, 0xBE, 0x31, 0x62, 0xC4, 0xC5, 0xC7, 0xC3, 0xCB, 0xDB, 0xFB, 0xBB,
   0x3B, 0x76, 0xEC, 0x95, 0x67, 0xCE, 0xD1, 0xEF, 0x93, 0x6B, 0xD6, 0xE1,
   0x8F, 0x53, 0xA6, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x4D,
   0x9A, 0x79, 0xF2, 0xA9, 0x1F, 0x3E, 0x7C, 0xF8, 0xBD, 0x37, 0x6E, 0xDC,
   0xF5, 0xA7, 0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0xC0, 0xCD, 0xD7, 0xE3,
   0x8B, 0x5B, 0xB6, 0x21, 0x42, 0x84, 0x45, 0x8A, 0x59, 0xB2, 0x29, 0x52,
   0xA4, 0x05, 0x0A, 0x14, 0x28, 0x50, 0xA0, 0x0D, 0x1A, 0x34, 0x68, 0xD0,
   0xED, 0x97, 0x63, 0xC6, 0xC1, 0xCF, 0xD3, 0xEB, 0x9B, 0x7B, 0xF6, 0xA1,
   0x0F, 0x1E, 0x3C, 0x78, 0xF0, 0xAD, 0x17, 0x2E, 0x5C, 0xB8, 0x3D, 0x7A,
   0xF4, 0xA5, 0x07, 0x0E, 0x1C, 0x38, 0x70, 0xE0, 0x8D, 0x57, 0xAE, 0x11,
   0x22, 0x44, 0x88, 0x5D, 0xBA, 0x39, 0x72, 0xE4, 0x85, 0x47, 0x8E, 0x51,
   0xA2, 0x09, 0x12, 0x24, 0x48, 0x90, 0x6D, 0xDA, 0xF9, 0xBF, 0x33, 0x66,
   0xCC, 0xD5, 0xE7, 0x83, 0x4B, 0x96, 0x61, 0xC2, 0xC9, 0xDF, 0xF3, 0xAB,
   0x1B, 0x36, 0x6C, 0xD8, 0xFD, 0xB7, 0x23, 0x46, 0x8C, 0x55, 0xAA, 0x19,
   0x32, 0x64, 0xC8, 0xDD, 0xF7, 0xA3, 0x0B, 0x16, 0x2C, 0x58, 0xB0, 0x2D,
   0x5A, 0xB4, 0x25, 0x4A, 0x94, 0x65, 0xCA, 0xD9, 0xFF, 0xB3, 0x2B, 0x56,
   0xAC, 0x15, 0x2A, 0x54, 0xA8, 0x1D, 0x3A, 0x74, 0xE8, 0x9D, 0x77, 0xEE,
   0x91, 0x6F, 0xDE, 0xF1, 0xAF, 0x13, 0x26, 0x4C, 0x98, 0x7D, 0xFA, 0xB9,
   0x3F, 0x7E, 0xFC, 0xB5, 0x27, 0x4E, 0x9C, 0x75, 0xEA, 0x99, 0x7F, 0xFE,
   0xB1, 0x2F, 0x5E, 0xBC, 0x35, 0x6A, 0xD4, 0xE5, 0x87, 0x43, 0x86, 0x41,
   0x82, 0x49, 0x92, 0x69, 0xD2, 0xE9, 0x9F, 0x73, 0xE6, 0x81, 0x4F, 0x9E,
   0x71, 0xE2, 0x89, 0x5F, 0xBE, 0x31, 0x62, 0xC4, 0xC5, 0xC7, 0xC3, 0xCB,
};


/* The table constants are indices of
 * S-box entries, preprocessed through q0 and q1. */
static byte calc_sb_tbl[512] = {
    0xA9, 0x75, 0x67, 0xF3, 0xB3, 0xC6, 0xE8, 0xF4,
    0x04, 0xDB, 0xFD, 0x7B, 0xA3, 0xFB, 0x76, 0xC8,
    0x9A, 0x4A, 0x92, 0xD3, 0x80, 0xE6, 0x78, 0x6B,
    0xE4, 0x45, 0xDD, 0x7D, 0xD1, 0xE8, 0x38, 0x4B,
    0x0D, 0xD6, 0xC6, 0x32, 0x35, 0xD8, 0x98, 0xFD,
    0x18, 0x37, 0xF7, 0x71, 0xEC, 0xF1, 0x6C, 0xE1,
    0x43, 0x30, 0x75, 0x0F, 0x37, 0xF8, 0x26, 0x1B,
    0xFA, 0x87, 0x13, 0xFA, 0x94, 0x06, 0x48, 0x3F,
    0xF2, 0x5E, 0xD0, 0xBA, 0x8B, 0xAE, 0x30, 0x5B,
    0x84, 0x8A, 0x54, 0x00, 0xDF, 0xBC, 0x23, 0x9D,
    0x19, 0x6D, 0x5B, 0xC1, 0x3D, 0xB1, 0x59, 0x0E,
    0xF3, 0x80, 0xAE, 0x5D, 0xA2, 0xD2, 0x82, 0xD5,
    0x63, 0xA0, 0x01, 0x84, 0x83, 0x07, 0x2E, 0x14,
    0xD9, 0xB5, 0x51, 0x90, 0x9B, 0x2C, 0x7C, 0xA3,
    0xA6, 0xB2, 0xEB, 0x73, 0xA5, 0x4C, 0xBE, 0x54,
    0x16, 0x92, 0x0C, 0x74, 0xE3, 0x36, 0x61, 0x51,
    0xC0, 0x38, 0x8C, 0xB0, 0x3A, 0xBD, 0xF5, 0x5A,
    0x73, 0xFC, 0x2C, 0x60, 0x25, 0x62, 0x0B, 0x96,
    0xBB, 0x6C, 0x4E, 0x42, 0x89, 0xF7, 0x6B, 0x10,
    0x53, 0x7C, 0x6A, 0x28, 0xB4, 0x27, 0xF1, 0x8C,
    0xE1, 0x13, 0xE6, 0x95, 0xBD, 0x9C, 0x45, 0xC7,
    0xE2, 0x24, 0xF4, 0x46, 0xB6, 0x3B, 0x66, 0x70,
    0xCC, 0xCA, 0x95, 0xE3, 0x03, 0x85, 0x56, 0xCB,
    0xD4, 0x11, 0x1C, 0xD0, 0x1E, 0x93, 0xD7, 0xB8,
    0xFB, 0xA6, 0xC3, 0x83, 0x8E, 0x20, 0xB5, 0xFF,
    0xE9, 0x9F, 0xCF, 0x77, 0xBF, 0xC3, 0xBA, 0xCC,
    0xEA, 0x03, 0x77, 0x6F, 0x39, 0x08, 0xAF, 0xBF,
    0x33, 0x40, 0xC9, 0xE7, 0x62, 0x2B, 0x71, 0xE2,
    0x81, 0x79, 0x79, 0x0C, 0x09, 0xAA, 0xAD, 0x82,
    0x24, 0x41, 0xCD, 0x3A, 0xF9, 0xEA, 0xD8, 0xB9,
    0xE5, 0xE4, 0xC5, 0x9A, 0xB9, 0xA4, 0x4D, 0x97,
    0x44, 0x7E, 0x08, 0xDA, 0x86, 0x7A, 0xE7, 0x17,
    0xA1, 0x66, 0x1D, 0x94, 0xAA, 0xA1, 0xED, 0x1D,
    0x06, 0x3D, 0x70, 0xF0, 0xB2, 0xDE, 0xD2, 0xB3,
    0x41, 0x0B, 0x7B, 0x72, 0xA0, 0xA7, 0x11, 0x1C,
    0x31, 0xEF, 0xC2, 0xD1, 0x27, 0x53, 0x90, 0x3E,
    0x20, 0x8F, 0xF6, 0x33, 0x60, 0x26, 0xFF, 0x5F,
    0x96, 0xEC, 0x5C, 0x76, 0xB1, 0x2A, 0xAB, 0x49,
    0x9E, 0x81, 0x9C, 0x88, 0x52, 0xEE, 0x1B, 0x21,
    0x5F, 0xC4, 0x93, 0x1A, 0x0A, 0xEB, 0xEF, 0xD9,
    0x91, 0xC5, 0x85, 0x39, 0x49, 0x99, 0xEE, 0xCD,
    0x2D, 0xAD, 0x4F, 0x31, 0x8F, 0x8B, 0x3B, 0x01,
    0x47, 0x18, 0x87, 0x23, 0x6D, 0xDD, 0x46, 0x1F,
    0xD6, 0x4E, 0x3E, 0x2D, 0x69, 0xF9, 0x64, 0x48,
    0x2A, 0x4F, 0xCE, 0xF2, 0xCB, 0x65, 0x2F, 0x8E,
    0xFC, 0x78, 0x97, 0x5C, 0x05, 0x58, 0x7A, 0x19,
    0xAC, 0x8D, 0x7F, 0xE5, 0xD5, 0x98, 0x1A, 0x57,
    0x4B, 0x67, 0x0E, 0x7F, 0xA7, 0x05, 0x5A, 0x64,
    0x28, 0xAF, 0x14, 0x63, 0x3F, 0xB6, 0x29, 0xFE,
    0x88, 0xF5, 0x3C, 0xB7, 0x4C, 0x3C, 0x02, 0xA5,
    0xB8, 0xCE, 0xDA, 0xE9, 0xB0, 0x68, 0x17, 0x44,
    0x55, 0xE0, 0x1F, 0x4D, 0x8A, 0x43, 0x7D, 0x69,
    0x57, 0x29, 0xC7, 0x2E, 0x8D, 0xAC, 0x74, 0x15,
    0xB7, 0x59, 0xC4, 0xA8, 0x9F, 0x0A, 0x72, 0x9E,
    0x7E, 0x6E, 0x15, 0x47, 0x22, 0xDF, 0x12, 0x34,
    0x58, 0x35, 0x07, 0x6A, 0x99, 0xCF, 0x34, 0xDC,
    0x6E, 0x22, 0x50, 0xC9, 0xDE, 0xC0, 0x68, 0x9B,
    0x65, 0x89, 0xBC, 0xD4, 0xDB, 0xED, 0xF8, 0xAB,
    0xC8, 0x12, 0xA8, 0xA2, 0x2B, 0x0D, 0x40, 0x52,
    0xDC, 0xBB, 0xFE, 0x02, 0x32, 0x2F, 0xA4, 0xA9,
    0xCA, 0xD7, 0x10, 0x61, 0x21, 0x1E, 0xF0, 0xB4,
    0xD3, 0x50, 0x5D, 0x04, 0x0F, 0xF6, 0x00, 0xC2,
    0x6F, 0x16, 0x9D, 0x25, 0x36, 0x86, 0x42, 0x56,
    0x4A, 0x55, 0x5E, 0x09, 0xC1, 0xBE, 0xE0, 0x91
};

/* Macro to perform one column of the RS matrix multiplication.  The
 * parameters a, b, c, and d are the four bytes of output; i is the index
 * of the key bytes, and w, x, y, and z, are the column of constants from
 * the RS matrix, preprocessed through the poly_to_exp table. */

#define CALC_S(a, b, c, d, i, w, x, y, z) \
   { \
      tmp = poly_to_exp[key[i]]; \
      (a) ^= exp_to_poly[tmp + (w)]; \
      (b) ^= exp_to_poly[tmp + (x)]; \
      (c) ^= exp_to_poly[tmp + (y)]; \
      (d) ^= exp_to_poly[tmp + (z)]; \
   }

/* Macros to calculate the key-dependent S-boxes for a 128-bit key using
 * the S vector from CALC_S.  CALC_SB_2 computes a single entry in all
 * four S-boxes, where i is the index of the entry to compute, and a and b
 * are the index numbers preprocessed through the q0 and q1 tables
 * respectively.  CALC_SB is simply a convenience to make the code shorter;
 * it calls CALC_SB_2 four times with consecutive indices from i to i+3,
 * using the remaining parameters two by two. */

#define CALC_SB_2(i, a, b) \
   ctx->s[0][i] = mds[0][q0[(a) ^ sa] ^ se]; \
   ctx->s[1][i] = mds[1][q0[(b) ^ sb] ^ sf]; \
   ctx->s[2][i] = mds[2][q1[(a) ^ sc] ^ sg]; \
   ctx->s[3][i] = mds[3][q1[(b) ^ sd] ^ sh]

#define CALC_SB(i, a, b, c, d, e, f, g, h) \
   CALC_SB_2 (i, a, b); CALC_SB_2 ((i)+1, c, d); \
   CALC_SB_2 ((i)+2, e, f); CALC_SB_2 ((i)+3, g, h)

/* Macros exactly like CALC_SB and CALC_SB_2, but for 256-bit keys. */

#define CALC_SB256_2(i, a, b) \
   ctx->s[0][i] = mds[0][q0[q0[q1[(b) ^ sa] ^ se] ^ si] ^ sm]; \
   ctx->s[1][i] = mds[1][q0[q1[q1[(a) ^ sb] ^ sf] ^ sj] ^ sn]; \
   ctx->s[2][i] = mds[2][q1[q0[q0[(a) ^ sc] ^ sg] ^ sk] ^ so]; \
   ctx->s[3][i] = mds[3][q1[q1[q0[(b) ^ sd] ^ sh] ^ sl] ^ sp];

#define CALC_SB256(i, a, b, c, d, e, f, g, h) \
   CALC_SB256_2 (i, a, b); CALC_SB256_2 ((i)+1, c, d); \
   CALC_SB256_2 ((i)+2, e, f); CALC_SB256_2 ((i)+3, g, h)

/* Macros to calculate the whitening and round subkeys.  CALC_K_2 computes the
 * last two stages of the h() function for a given index (either 2i or 2i+1).
 * a, b, c, and d are the four bytes going into the last two stages.  For
 * 128-bit keys, this is the entire h() function and a and c are the index
 * preprocessed through q0 and q1 respectively; for longer keys they are the
 * output of previous stages.  j is the index of the first key byte to use.
 * CALC_K computes a pair of subkeys for 128-bit Twofish, by calling CALC_K_2
 * twice, doing the Pseudo-Hadamard Transform, and doing the necessary
 * rotations.  Its parameters are: a, the array to write the results into,
 * j, the index of the first output entry, k and l, the preprocessed indices
 * for index 2i, and m and n, the preprocessed indices for index 2i+1.
 * CALC_K256_2 expands CALC_K_2 to handle 256-bit keys, by doing two
 * additional lookup-and-XOR stages.  The parameters a and b are the index
 * preprocessed through q0 and q1 respectively; j is the index of the first
 * key byte to use.  CALC_K256 is identical to CALC_K but for using the
 * CALC_K256_2 macro instead of CALC_K_2. */

#define CALC_K_2(a, b, c, d, j) \
     mds[0][q0[a ^ key[(j) + 8]] ^ key[j]] \
   ^ mds[1][q0[b ^ key[(j) + 9]] ^ key[(j) + 1]] \
   ^ mds[2][q1[c ^ key[(j) + 10]] ^ key[(j) + 2]] \
   ^ mds[3][q1[d ^ key[(j) + 11]] ^ key[(j) + 3]]

#define CALC_K(a, j, k, l, m, n) \
   x = CALC_K_2 (k, l, k, l, 0); \
   y = CALC_K_2 (m, n, m, n, 4); \
   y = (y << 8) + (y >> 24); \
   x += y; y += x; ctx->a[j] = x; \
   ctx->a[(j) + 1] = (y << 9) + (y >> 23)

#define CALC_K256_2(a, b, j) \
   CALC_K_2 (q0[q1[b ^ key[(j) + 24]] ^ key[(j) + 16]], \
	     q1[q1[a ^ key[(j) + 25]] ^ key[(j) + 17]], \
	     q0[q0[a ^ key[(j) + 26]] ^ key[(j) + 18]], \
	     q1[q0[b ^ key[(j) + 27]] ^ key[(j) + 19]], j)

#define CALC_K256(a, j, k, l, m, n) \
   x = CALC_K256_2 (k, l, 0); \
   y = CALC_K256_2 (m, n, 4); \
   y = (y << 8) + (y >> 24); \
   x += y; y += x; ctx->a[j] = x; \
   ctx->a[(j) + 1] = (y << 9) + (y >> 23)



/* Perform the key setup.  Note that this works only with 128- and 256-bit
 * keys, despite the API that looks like it might support other sizes. */

static gcry_err_code_t
do_twofish_setkey (TWOFISH_context *ctx, const byte *key, const unsigned keylen)
{
  int i, j, k;

  /* Temporaries for CALC_K. */
  u32 x, y;

  /* The S vector used to key the S-boxes, split up into individual bytes.
   * 128-bit keys use only sa through sh; 256-bit use all of them. */
  byte sa = 0, sb = 0, sc = 0, sd = 0, se = 0, sf = 0, sg = 0, sh = 0;
  byte si = 0, sj = 0, sk = 0, sl = 0, sm = 0, sn = 0, so = 0, sp = 0;

  /* Temporary for CALC_S. */
  unsigned int tmp;

  /* Flags for self-test. */
  static int initialized = 0;
  static const char *selftest_failed=0;

  /* Check key length. */
  if( ( ( keylen - 16 ) | 16 ) != 16 )
    return GPG_ERR_INV_KEYLEN;

  /* Do self-test if necessary. */
  if (!initialized)
    {
      initialized = 1;
      selftest_failed = selftest ();
      if( selftest_failed )
        log_error("%s\n", selftest_failed );
    }
  if( selftest_failed )
    return GPG_ERR_SELFTEST_FAILED;

  /* Compute the first two words of the S vector.  The magic numbers are
   * the entries of the RS matrix, preprocessed through poly_to_exp.	The
   * numbers in the comments are the original (polynomial form) matrix
   * entries. */
  CALC_S (sa, sb, sc, sd, 0, 0x00, 0x2D, 0x01, 0x2D); /* 01 A4 02 A4 */
  CALC_S (sa, sb, sc, sd, 1, 0x2D, 0xA4, 0x44, 0x8A); /* A4 56 A1 55 */
  CALC_S (sa, sb, sc, sd, 2, 0x8A, 0xD5, 0xBF, 0xD1); /* 55 82 FC 87 */
  CALC_S (sa, sb, sc, sd, 3, 0xD1, 0x7F, 0x3D, 0x99); /* 87 F3 C1 5A */
  CALC_S (sa, sb, sc, sd, 4, 0x99, 0x46, 0x66, 0x96); /* 5A 1E 47 58 */
  CALC_S (sa, sb, sc, sd, 5, 0x96, 0x3C, 0x5B, 0xED); /* 58 C6 AE DB */
  CALC_S (sa, sb, sc, sd, 6, 0xED, 0x37, 0x4F, 0xE0); /* DB 68 3D 9E */
  CALC_S (sa, sb, sc, sd, 7, 0xE0, 0xD0, 0x8C, 0x17); /* 9E E5 19 03 */
  CALC_S (se, sf, sg, sh, 8, 0x00, 0x2D, 0x01, 0x2D); /* 01 A4 02 A4 */
  CALC_S (se, sf, sg, sh, 9, 0x2D, 0xA4, 0x44, 0x8A); /* A4 56 A1 55 */
  CALC_S (se, sf, sg, sh, 10, 0x8A, 0xD5, 0xBF, 0xD1); /* 55 82 FC 87 */
  CALC_S (se, sf, sg, sh, 11, 0xD1, 0x7F, 0x3D, 0x99); /* 87 F3 C1 5A */
  CALC_S (se, sf, sg, sh, 12, 0x99, 0x46, 0x66, 0x96); /* 5A 1E 47 58 */
  CALC_S (se, sf, sg, sh, 13, 0x96, 0x3C, 0x5B, 0xED); /* 58 C6 AE DB */
  CALC_S (se, sf, sg, sh, 14, 0xED, 0x37, 0x4F, 0xE0); /* DB 68 3D 9E */
  CALC_S (se, sf, sg, sh, 15, 0xE0, 0xD0, 0x8C, 0x17); /* 9E E5 19 03 */

  if (keylen == 32)  /* 256-bit key */
    {
      /* Calculate the remaining two words of the S vector */
      CALC_S (si, sj, sk, sl, 16, 0x00, 0x2D, 0x01, 0x2D); /* 01 A4 02 A4 */
      CALC_S (si, sj, sk, sl, 17, 0x2D, 0xA4, 0x44, 0x8A); /* A4 56 A1 55 */
      CALC_S (si, sj, sk, sl, 18, 0x8A, 0xD5, 0xBF, 0xD1); /* 55 82 FC 87 */
      CALC_S (si, sj, sk, sl, 19, 0xD1, 0x7F, 0x3D, 0x99); /* 87 F3 C1 5A */
      CALC_S (si, sj, sk, sl, 20, 0x99, 0x46, 0x66, 0x96); /* 5A 1E 47 58 */
      CALC_S (si, sj, sk, sl, 21, 0x96, 0x3C, 0x5B, 0xED); /* 58 C6 AE DB */
      CALC_S (si, sj, sk, sl, 22, 0xED, 0x37, 0x4F, 0xE0); /* DB 68 3D 9E */
      CALC_S (si, sj, sk, sl, 23, 0xE0, 0xD0, 0x8C, 0x17); /* 9E E5 19 03 */
      CALC_S (sm, sn, so, sp, 24, 0x00, 0x2D, 0x01, 0x2D); /* 01 A4 02 A4 */
      CALC_S (sm, sn, so, sp, 25, 0x2D, 0xA4, 0x44, 0x8A); /* A4 56 A1 55 */
      CALC_S (sm, sn, so, sp, 26, 0x8A, 0xD5, 0xBF, 0xD1); /* 55 82 FC 87 */
      CALC_S (sm, sn, so, sp, 27, 0xD1, 0x7F, 0x3D, 0x99); /* 87 F3 C1 5A */
      CALC_S (sm, sn, so, sp, 28, 0x99, 0x46, 0x66, 0x96); /* 5A 1E 47 58 */
      CALC_S (sm, sn, so, sp, 29, 0x96, 0x3C, 0x5B, 0xED); /* 58 C6 AE DB */
      CALC_S (sm, sn, so, sp, 30, 0xED, 0x37, 0x4F, 0xE0); /* DB 68 3D 9E */
      CALC_S (sm, sn, so, sp, 31, 0xE0, 0xD0, 0x8C, 0x17); /* 9E E5 19 03 */

      /* Compute the S-boxes. */
      for(i=j=0,k=1; i < 256; i++, j += 2, k += 2 )
        {
          CALC_SB256_2( i, calc_sb_tbl[j], calc_sb_tbl[k] );
	}

      /* Calculate whitening and round subkeys. */
      for (i = 0; i < 8; i += 2)
	{
	  CALC_K256 ( w, i, q0[i], q1[i], q0[i + 1], q1[i + 1] );
	}
      for (j = 0; j < 32; j += 2, i += 2)
	{
	  CALC_K256 ( k, j, q0[i], q1[i], q0[i + 1], q1[i + 1] );
	}
    }
  else
    {
      /* Compute the S-boxes. */
      for(i=j=0,k=1; i < 256; i++, j += 2, k += 2 )
        {
          CALC_SB_2( i, calc_sb_tbl[j], calc_sb_tbl[k] );
        }

      /* Calculate whitening and round subkeys. */
      for (i = 0; i < 8; i += 2)
	{
	  CALC_K ( w, i, q0[i], q1[i], q0[i + 1], q1[i + 1] );
	}
      for (j = 0; j < 32; j += 2, i += 2)
	{
	  CALC_K ( k, j, q0[i], q1[i], q0[i + 1], q1[i + 1] );
	}
    }

  return 0;
}

static gcry_err_code_t
twofish_setkey (void *context, const byte *key, unsigned int keylen,
                cipher_bulk_ops_t *bulk_ops)
{
  TWOFISH_context *ctx = context;
  unsigned int hwfeatures = _gcry_get_hw_features ();
  int rc;

  rc = do_twofish_setkey (ctx, key, keylen);

#ifdef USE_AVX2
  ctx->use_avx2 = 0;
  if ((hwfeatures & HWF_INTEL_AVX2) && (hwfeatures & HWF_INTEL_FAST_VPGATHER))
    {
      ctx->use_avx2 = 1;
    }
#endif

  /* Setup bulk encryption routines.  */
  memset (bulk_ops, 0, sizeof(*bulk_ops));
  bulk_ops->cbc_dec = _gcry_twofish_cbc_dec;
  bulk_ops->cfb_dec = _gcry_twofish_cfb_dec;
  bulk_ops->ctr_enc = _gcry_twofish_ctr_enc;
  bulk_ops->ocb_crypt = _gcry_twofish_ocb_crypt;
  bulk_ops->ocb_auth  = _gcry_twofish_ocb_auth;

  (void)hwfeatures;

  _gcry_burn_stack (23+6*sizeof(void*));
  return rc;
}


#ifdef USE_AVX2
/* Assembler implementations of Twofish using AVX2.  Process 16 block in
   parallel.
 */
extern void _gcry_twofish_avx2_ctr_enc(const TWOFISH_context *ctx,
				       unsigned char *out,
				       const unsigned char *in,
				       unsigned char *ctr) ASM_FUNC_ABI;

extern void _gcry_twofish_avx2_cbc_dec(const TWOFISH_context *ctx,
				       unsigned char *out,
				       const unsigned char *in,
				       unsigned char *iv) ASM_FUNC_ABI;

extern void _gcry_twofish_avx2_cfb_dec(const TWOFISH_context *ctx,
				       unsigned char *out,
				       const unsigned char *in,
				       unsigned char *iv) ASM_FUNC_ABI;

extern void _gcry_twofish_avx2_ocb_enc(const TWOFISH_context *ctx,
				       unsigned char *out,
				       const unsigned char *in,
				       unsigned char *offset,
				       unsigned char *checksum,
				       const u64 Ls[16]) ASM_FUNC_ABI;

extern void _gcry_twofish_avx2_ocb_dec(const TWOFISH_context *ctx,
				       unsigned char *out,
				       const unsigned char *in,
				       unsigned char *offset,
				       unsigned char *checksum,
				       const u64 Ls[16]) ASM_FUNC_ABI;

extern void _gcry_twofish_avx2_ocb_auth(const TWOFISH_context *ctx,
					const unsigned char *abuf,
					unsigned char *offset,
					unsigned char *checksum,
					const u64 Ls[16]) ASM_FUNC_ABI;
#endif


#ifdef USE_AMD64_ASM

/* Assembly implementations of Twofish. */
extern void _gcry_twofish_amd64_encrypt_block(const TWOFISH_context *c,
					      byte *out, const byte *in);

extern void _gcry_twofish_amd64_decrypt_block(const TWOFISH_context *c,
					      byte *out, const byte *in);

/* These assembly implementations process three blocks in parallel. */
extern void _gcry_twofish_amd64_ctr_enc(const TWOFISH_context *c, byte *out,
					const byte *in, byte *ctr);

extern void _gcry_twofish_amd64_cbc_dec(const TWOFISH_context *c, byte *out,
					const byte *in, byte *iv);

extern void _gcry_twofish_amd64_cfb_dec(const TWOFISH_context *c, byte *out,
					const byte *in, byte *iv);

extern void _gcry_twofish_amd64_ocb_enc(const TWOFISH_context *ctx, byte *out,
					const byte *in, byte *offset,
					byte *checksum, const u64 Ls[3]);

extern void _gcry_twofish_amd64_ocb_dec(const TWOFISH_context *ctx, byte *out,
					const byte *in, byte *offset,
					byte *checksum, const u64 Ls[3]);

extern void _gcry_twofish_amd64_ocb_auth(const TWOFISH_context *ctx,
					 const byte *abuf, byte *offset,
					 byte *checksum, const u64 Ls[3]);

static inline void
twofish_amd64_encrypt_block(const TWOFISH_context *c, byte *out, const byte *in)
{
  _gcry_twofish_amd64_encrypt_block(c, out, in);
}

static inline void
twofish_amd64_decrypt_block(const TWOFISH_context *c, byte *out, const byte *in)
{
  _gcry_twofish_amd64_decrypt_block(c, out, in);
}

static inline void
twofish_amd64_ctr_enc(const TWOFISH_context *c, byte *out, const byte *in,
                      byte *ctr)
{
  _gcry_twofish_amd64_ctr_enc(c, out, in, ctr);
}

static inline void
twofish_amd64_cbc_dec(const TWOFISH_context *c, byte *out, const byte *in,
                      byte *iv)
{
  _gcry_twofish_amd64_cbc_dec(c, out, in, iv);
}

static inline void
twofish_amd64_cfb_dec(const TWOFISH_context *c, byte *out, const byte *in,
                      byte *iv)
{
  _gcry_twofish_amd64_cfb_dec(c, out, in, iv);
}

static inline void
twofish_amd64_ocb_enc(const TWOFISH_context *ctx, byte *out, const byte *in,
		      byte *offset, byte *checksum, const u64 Ls[3])
{
  _gcry_twofish_amd64_ocb_enc(ctx, out, in, offset, checksum, Ls);
}

static inline void
twofish_amd64_ocb_dec(const TWOFISH_context *ctx, byte *out, const byte *in,
		      byte *offset, byte *checksum, const u64 Ls[3])
{
  _gcry_twofish_amd64_ocb_dec(ctx, out, in, offset, checksum, Ls);
}

static inline void
twofish_amd64_ocb_auth(const TWOFISH_context *ctx, const byte *abuf,
		       byte *offset, byte *checksum, const u64 Ls[3])
{
  _gcry_twofish_amd64_ocb_auth(ctx, abuf, offset, checksum, Ls);
}

#elif defined(USE_ARM_ASM)

/* Assembly implementations of Twofish. */
extern void _gcry_twofish_arm_encrypt_block(const TWOFISH_context *c,
					      byte *out, const byte *in);

extern void _gcry_twofish_arm_decrypt_block(const TWOFISH_context *c,
					      byte *out, const byte *in);

#else /*!USE_AMD64_ASM && !USE_ARM_ASM*/

/* Macros to compute the g() function in the encryption and decryption
 * rounds.  G1 is the straight g() function; G2 includes the 8-bit
 * rotation for the high 32-bit word. */

#define G1(a) \
     (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) >> 8) & 0xFF]) \
   ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s[3][(a) >> 24])

#define G2(b) \
     (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) >> 8) & 0xFF]) \
   ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s[0][(b) >> 24])

/* Encryption and decryption Feistel rounds.  Each one calls the two g()
 * macros, does the PHT, and performs the XOR and the appropriate bit
 * rotations.  The parameters are the round number (used to select subkeys),
 * and the four 32-bit chunks of the text. */

#define ENCROUND(n, a, b, c, d) \
   x = G1 (a); y = G2 (b); \
   x += y; y += x + ctx->k[2 * (n) + 1]; \
   (c) ^= x + ctx->k[2 * (n)]; \
   (c) = ((c) >> 1) + ((c) << 31); \
   (d) = (((d) << 1)+((d) >> 31)) ^ y

#define DECROUND(n, a, b, c, d) \
   x = G1 (a); y = G2 (b); \
   x += y; y += x; \
   (d) ^= y + ctx->k[2 * (n) + 1]; \
   (d) = ((d) >> 1) + ((d) << 31); \
   (c) = (((c) << 1)+((c) >> 31)); \
   (c) ^= (x + ctx->k[2 * (n)])

/* Encryption and decryption cycles; each one is simply two Feistel rounds
 * with the 32-bit chunks re-ordered to simulate the "swap" */

#define ENCCYCLE(n) \
   ENCROUND (2 * (n), a, b, c, d); \
   ENCROUND (2 * (n) + 1, c, d, a, b)

#define DECCYCLE(n) \
   DECROUND (2 * (n) + 1, c, d, a, b); \
   DECROUND (2 * (n), a, b, c, d)

/* Macros to convert the input and output bytes into 32-bit words,
 * and simultaneously perform the whitening step.  INPACK packs word
 * number n into the variable named by x, using whitening subkey number m.
 * OUTUNPACK unpacks word number n from the variable named by x, using
 * whitening subkey number m. */

#define INPACK(n, x, m) \
   x = buf_get_le32(in + (n) * 4); \
   x ^= ctx->w[m]

#define OUTUNPACK(n, x, m) \
   x ^= ctx->w[m]; \
   buf_put_le32(out + (n) * 4, x)

#endif /*!USE_AMD64_ASM*/


/* Encrypt one block.  in and out may be the same. */

#ifdef USE_AMD64_ASM

static unsigned int
twofish_encrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;
  twofish_amd64_encrypt_block(ctx, out, in);
  return /*burn_stack*/ (4*sizeof (void*));
}

#elif defined(USE_ARM_ASM)

static unsigned int
twofish_encrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;
  _gcry_twofish_arm_encrypt_block(ctx, out, in);
  return /*burn_stack*/ (4*sizeof (void*));
}

#else /*!USE_AMD64_ASM && !USE_ARM_ASM*/

static void
do_twofish_encrypt (const TWOFISH_context *ctx, byte *out, const byte *in)
{
  /* The four 32-bit chunks of the text. */
  u32 a, b, c, d;

  /* Temporaries used by the round function. */
  u32 x, y;

  /* Input whitening and packing. */
  INPACK (0, a, 0);
  INPACK (1, b, 1);
  INPACK (2, c, 2);
  INPACK (3, d, 3);

  /* Encryption Feistel cycles. */
  ENCCYCLE (0);
  ENCCYCLE (1);
  ENCCYCLE (2);
  ENCCYCLE (3);
  ENCCYCLE (4);
  ENCCYCLE (5);
  ENCCYCLE (6);
  ENCCYCLE (7);

  /* Output whitening and unpacking. */
  OUTUNPACK (0, c, 4);
  OUTUNPACK (1, d, 5);
  OUTUNPACK (2, a, 6);
  OUTUNPACK (3, b, 7);
}

static unsigned int
twofish_encrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;
  do_twofish_encrypt (ctx, out, in);
  return /*burn_stack*/ (24+3*sizeof (void*));
}

#endif /*!USE_AMD64_ASM && !USE_ARM_ASM*/


/* Decrypt one block.  in and out may be the same. */

#ifdef USE_AMD64_ASM

static unsigned int
twofish_decrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;
  twofish_amd64_decrypt_block(ctx, out, in);
  return /*burn_stack*/ (4*sizeof (void*));
}

#elif defined(USE_ARM_ASM)

static unsigned int
twofish_decrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;
  _gcry_twofish_arm_decrypt_block(ctx, out, in);
  return /*burn_stack*/ (4*sizeof (void*));
}

#else /*!USE_AMD64_ASM && !USE_ARM_ASM*/

static void
do_twofish_decrypt (const TWOFISH_context *ctx, byte *out, const byte *in)
{
  /* The four 32-bit chunks of the text. */
  u32 a, b, c, d;

  /* Temporaries used by the round function. */
  u32 x, y;

  /* Input whitening and packing. */
  INPACK (0, c, 4);
  INPACK (1, d, 5);
  INPACK (2, a, 6);
  INPACK (3, b, 7);

  /* Encryption Feistel cycles. */
  DECCYCLE (7);
  DECCYCLE (6);
  DECCYCLE (5);
  DECCYCLE (4);
  DECCYCLE (3);
  DECCYCLE (2);
  DECCYCLE (1);
  DECCYCLE (0);

  /* Output whitening and unpacking. */
  OUTUNPACK (0, a, 0);
  OUTUNPACK (1, b, 1);
  OUTUNPACK (2, c, 2);
  OUTUNPACK (3, d, 3);
}

static unsigned int
twofish_decrypt (void *context, byte *out, const byte *in)
{
  TWOFISH_context *ctx = context;

  do_twofish_decrypt (ctx, out, in);
  return /*burn_stack*/ (24+3*sizeof (void*));
}

#endif /*!USE_AMD64_ASM && !USE_ARM_ASM*/



/* Bulk encryption of complete blocks in CTR mode.  This function is only
   intended for the bulk encryption feature of cipher.c.  CTR is expected to be
   of size TWOFISH_BLOCKSIZE. */
static void
_gcry_twofish_ctr_enc(void *context, unsigned char *ctr, void *outbuf_arg,
		      const void *inbuf_arg, size_t nblocks)
{
  TWOFISH_context *ctx = context;
  unsigned char *outbuf = outbuf_arg;
  const unsigned char *inbuf = inbuf_arg;
  unsigned char tmpbuf[TWOFISH_BLOCKSIZE];
  unsigned int burn, burn_stack_depth = 0;

#ifdef USE_AVX2
  if (ctx->use_avx2)
    {
      int did_use_avx2 = 0;

      /* Process data in 16 block chunks. */
      while (nblocks >= 16)
        {
          _gcry_twofish_avx2_ctr_enc(ctx, outbuf, inbuf, ctr);

          nblocks -= 16;
          outbuf += 16 * TWOFISH_BLOCKSIZE;
          inbuf  += 16 * TWOFISH_BLOCKSIZE;
          did_use_avx2 = 1;
        }

      if (did_use_avx2)
        {
          /* twofish-avx2 assembly code does not use stack */
          if (nblocks == 0)
            burn_stack_depth = 0;
        }
    }
#endif

#ifdef USE_AMD64_ASM
  {
    /* Process data in 3 block chunks. */
    while (nblocks >= 3)
      {
        twofish_amd64_ctr_enc(ctx, outbuf, inbuf, ctr);

        nblocks -= 3;
        outbuf += 3 * TWOFISH_BLOCKSIZE;
        inbuf += 3 * TWOFISH_BLOCKSIZE;

        burn = 8 * sizeof(void*);
        if (burn > burn_stack_depth)
          burn_stack_depth = burn;
      }

    /* Use generic code to handle smaller chunks... */
    /* TODO: use caching instead? */
  }
#endif

  for ( ;nblocks; nblocks-- )
    {
      /* Encrypt the counter. */
      burn = twofish_encrypt(ctx, tmpbuf, ctr);
      if (burn > burn_stack_depth)
        burn_stack_depth = burn;

      /* XOR the input with the encrypted counter and store in output.  */
      cipher_block_xor(outbuf, tmpbuf, inbuf, TWOFISH_BLOCKSIZE);
      outbuf += TWOFISH_BLOCKSIZE;
      inbuf  += TWOFISH_BLOCKSIZE;
      /* Increment the counter.  */
      cipher_block_add(ctr, 1, TWOFISH_BLOCKSIZE);
    }

  wipememory(tmpbuf, sizeof(tmpbuf));
  _gcry_burn_stack(burn_stack_depth);
}


/* Bulk decryption of complete blocks in CBC mode.  This function is only
   intended for the bulk encryption feature of cipher.c. */
static void
_gcry_twofish_cbc_dec(void *context, unsigned char *iv, void *outbuf_arg,
		      const void *inbuf_arg, size_t nblocks)
{
  TWOFISH_context *ctx = context;
  unsigned char *outbuf = outbuf_arg;
  const unsigned char *inbuf = inbuf_arg;
  unsigned char savebuf[TWOFISH_BLOCKSIZE];
  unsigned int burn, burn_stack_depth = 0;

#ifdef USE_AVX2
  if (ctx->use_avx2)
    {
      int did_use_avx2 = 0;

      /* Process data in 16 block chunks. */
      while (nblocks >= 16)
        {
          _gcry_twofish_avx2_cbc_dec(ctx, outbuf, inbuf, iv);

          nblocks -= 16;
          outbuf += 16 * TWOFISH_BLOCKSIZE;
          inbuf  += 16 * TWOFISH_BLOCKSIZE;
          did_use_avx2 = 1;
        }

      if (did_use_avx2)
        {
          /* twofish-avx2 assembly code does not use stack */
          if (nblocks == 0)
            burn_stack_depth = 0;
        }
    }
#endif

#ifdef USE_AMD64_ASM
  {
    /* Process data in 3 block chunks. */
    while (nblocks >= 3)
      {
        twofish_amd64_cbc_dec(ctx, outbuf, inbuf, iv);

        nblocks -= 3;
        outbuf += 3 * TWOFISH_BLOCKSIZE;
        inbuf += 3 * TWOFISH_BLOCKSIZE;

        burn = 9 * sizeof(void*);
        if (burn > burn_stack_depth)
          burn_stack_depth = burn;
      }

    /* Use generic code to handle smaller chunks... */
  }
#endif

  for ( ;nblocks; nblocks-- )
    {
      /* INBUF is needed later and it may be identical to OUTBUF, so store
         the intermediate result to SAVEBUF.  */
      burn = twofish_decrypt (ctx, savebuf, inbuf);
      if (burn > burn_stack_depth)
        burn_stack_depth = burn;

      cipher_block_xor_n_copy_2(outbuf, savebuf, iv, inbuf, TWOFISH_BLOCKSIZE);
      inbuf += TWOFISH_BLOCKSIZE;
      outbuf += TWOFISH_BLOCKSIZE;
    }

  wipememory(savebuf, sizeof(savebuf));
  _gcry_burn_stack(burn_stack_depth);
}


/* Bulk decryption of complete blocks in CFB mode.  This function is only
   intended for the bulk encryption feature of cipher.c. */
static void
_gcry_twofish_cfb_dec(void *context, unsigned char *iv, void *outbuf_arg,
		    const void *inbuf_arg, size_t nblocks)
{
  TWOFISH_context *ctx = context;
  unsigned char *outbuf = outbuf_arg;
  const unsigned char *inbuf = inbuf_arg;
  unsigned int burn, burn_stack_depth = 0;

#ifdef USE_AVX2
  if (ctx->use_avx2)
    {
      int did_use_avx2 = 0;

      /* Process data in 16 block chunks. */
      while (nblocks >= 16)
        {
          _gcry_twofish_avx2_cfb_dec(ctx, outbuf, inbuf, iv);

          nblocks -= 16;
          outbuf += 16 * TWOFISH_BLOCKSIZE;
          inbuf  += 16 * TWOFISH_BLOCKSIZE;
          did_use_avx2 = 1;
        }

      if (did_use_avx2)
        {
          /* twofish-avx2 assembly code does not use stack */
          if (nblocks == 0)
            burn_stack_depth = 0;
        }
    }
#endif

#ifdef USE_AMD64_ASM
  {
    /* Process data in 3 block chunks. */
    while (nblocks >= 3)
      {
        twofish_amd64_cfb_dec(ctx, outbuf, inbuf, iv);

        nblocks -= 3;
        outbuf += 3 * TWOFISH_BLOCKSIZE;
        inbuf += 3 * TWOFISH_BLOCKSIZE;

        burn = 8 * sizeof(void*);
        if (burn > burn_stack_depth)
          burn_stack_depth = burn;
      }

    /* Use generic code to handle smaller chunks... */
  }
#endif

  for ( ;nblocks; nblocks-- )
    {
      burn = twofish_encrypt(ctx, iv, iv);
      if (burn > burn_stack_depth)
        burn_stack_depth = burn;

      cipher_block_xor_n_copy(outbuf, iv, inbuf, TWOFISH_BLOCKSIZE);
      outbuf += TWOFISH_BLOCKSIZE;
      inbuf += TWOFISH_BLOCKSIZE;
    }

  _gcry_burn_stack(burn_stack_depth);
}

/* Bulk encryption/decryption of complete blocks in OCB mode. */
static size_t
_gcry_twofish_ocb_crypt (gcry_cipher_hd_t c, void *outbuf_arg,
			const void *inbuf_arg, size_t nblocks, int encrypt)
{
#ifdef USE_AMD64_ASM
  TWOFISH_context *ctx = (void *)&c->context.c;
  unsigned char *outbuf = outbuf_arg;
  const unsigned char *inbuf = inbuf_arg;
  unsigned int burn, burn_stack_depth = 0;
  u64 blkn = c->u_mode.ocb.data_nblocks;

#ifdef USE_AVX2
  if (ctx->use_avx2)
    {
      int did_use_avx2 = 0;
      u64 Ls[16];
      unsigned int n = 16 - (blkn % 16);
      u64 *l;
      int i;

      if (nblocks >= 16)
	{
	  for (i = 0; i < 16; i += 8)
	    {
	      /* Use u64 to store pointers for x32 support (assembly function
	       * assumes 64-bit pointers). */
	      Ls[(i + 0 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 1 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[1];
	      Ls[(i + 2 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 3 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[2];
	      Ls[(i + 4 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 5 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[1];
	      Ls[(i + 6 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	    }

	  Ls[(7 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[3];
	  l = &Ls[(15 + n) % 16];

	  /* Process data in 16 block chunks. */
	  while (nblocks >= 16)
	    {
	      blkn += 16;
	      *l = (uintptr_t)(void *)ocb_get_l(c, blkn - blkn % 16);

	      if (encrypt)
		_gcry_twofish_avx2_ocb_enc(ctx, outbuf, inbuf, c->u_iv.iv,
					  c->u_ctr.ctr, Ls);
	      else
		_gcry_twofish_avx2_ocb_dec(ctx, outbuf, inbuf, c->u_iv.iv,
					  c->u_ctr.ctr, Ls);

	      nblocks -= 16;
	      outbuf += 16 * TWOFISH_BLOCKSIZE;
	      inbuf  += 16 * TWOFISH_BLOCKSIZE;
	      did_use_avx2 = 1;
	    }
	}

      if (did_use_avx2)
	{
	  /* twofish-avx2 assembly code does not use stack */
	  if (nblocks == 0)
	    burn_stack_depth = 0;
	}
    }
#endif

  {
    /* Use u64 to store pointers for x32 support (assembly function
      * assumes 64-bit pointers). */
    u64 Ls[3];

    /* Process data in 3 block chunks. */
    while (nblocks >= 3)
      {
	Ls[0] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 1);
	Ls[1] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 2);
	Ls[2] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 3);
	blkn += 3;

	if (encrypt)
	  twofish_amd64_ocb_enc(ctx, outbuf, inbuf, c->u_iv.iv, c->u_ctr.ctr,
				Ls);
	else
	  twofish_amd64_ocb_dec(ctx, outbuf, inbuf, c->u_iv.iv, c->u_ctr.ctr,
				Ls);

	nblocks -= 3;
	outbuf += 3 * TWOFISH_BLOCKSIZE;
	inbuf  += 3 * TWOFISH_BLOCKSIZE;

	burn = 8 * sizeof(void*);
	if (burn > burn_stack_depth)
	  burn_stack_depth = burn;
      }

    /* Use generic code to handle smaller chunks... */
  }

  c->u_mode.ocb.data_nblocks = blkn;

  if (burn_stack_depth)
    _gcry_burn_stack (burn_stack_depth + 4 * sizeof(void *));
#else
  (void)c;
  (void)outbuf_arg;
  (void)inbuf_arg;
  (void)encrypt;
#endif

  return nblocks;
}

/* Bulk authentication of complete blocks in OCB mode. */
static size_t
_gcry_twofish_ocb_auth (gcry_cipher_hd_t c, const void *abuf_arg,
			size_t nblocks)
{
#ifdef USE_AMD64_ASM
  TWOFISH_context *ctx = (void *)&c->context.c;
  const unsigned char *abuf = abuf_arg;
  unsigned int burn, burn_stack_depth = 0;
  u64 blkn = c->u_mode.ocb.aad_nblocks;

#ifdef USE_AVX2
  if (ctx->use_avx2)
    {
      int did_use_avx2 = 0;
      u64 Ls[16];
      unsigned int n = 16 - (blkn % 16);
      u64 *l;
      int i;

      if (nblocks >= 16)
	{
	  for (i = 0; i < 16; i += 8)
	    {
	      /* Use u64 to store pointers for x32 support (assembly function
	       * assumes 64-bit pointers). */
	      Ls[(i + 0 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 1 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[1];
	      Ls[(i + 2 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 3 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[2];
	      Ls[(i + 4 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	      Ls[(i + 5 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[1];
	      Ls[(i + 6 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[0];
	    }

	  Ls[(7 + n) % 16] = (uintptr_t)(void *)c->u_mode.ocb.L[3];
	  l = &Ls[(15 + n) % 16];

	  /* Process data in 16 block chunks. */
	  while (nblocks >= 16)
	    {
	      blkn += 16;
	      *l = (uintptr_t)(void *)ocb_get_l(c, blkn - blkn % 16);

	      _gcry_twofish_avx2_ocb_auth(ctx, abuf, c->u_mode.ocb.aad_offset,
					  c->u_mode.ocb.aad_sum, Ls);

	      nblocks -= 16;
	      abuf += 16 * TWOFISH_BLOCKSIZE;
	      did_use_avx2 = 1;
	    }
	}

      if (did_use_avx2)
	{
	  /* twofish-avx2 assembly code does not use stack */
	  if (nblocks == 0)
	    burn_stack_depth = 0;
	}

      /* Use generic code to handle smaller chunks... */
    }
#endif

  {
    /* Use u64 to store pointers for x32 support (assembly function
      * assumes 64-bit pointers). */
    u64 Ls[3];

    /* Process data in 3 block chunks. */
    while (nblocks >= 3)
      {
	Ls[0] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 1);
	Ls[1] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 2);
	Ls[2] = (uintptr_t)(const void *)ocb_get_l(c, blkn + 3);
	blkn += 3;

	twofish_amd64_ocb_auth(ctx, abuf, c->u_mode.ocb.aad_offset,
			      c->u_mode.ocb.aad_sum, Ls);

	nblocks -= 3;
	abuf += 3 * TWOFISH_BLOCKSIZE;

	burn = 8 * sizeof(void*);
	if (burn > burn_stack_depth)
	  burn_stack_depth = burn;
      }

    /* Use generic code to handle smaller chunks... */
  }

  c->u_mode.ocb.aad_nblocks = blkn;

  if (burn_stack_depth)
    _gcry_burn_stack (burn_stack_depth + 4 * sizeof(void *));
#else
  (void)c;
  (void)abuf_arg;
#endif

  return nblocks;
}



/* Run the self-tests for TWOFISH-CTR, tests IV increment of bulk CTR
   encryption.  Returns NULL on success. */
static const char *
selftest_ctr (void)
{
  const int nblocks = 16+1;
  const int blocksize = TWOFISH_BLOCKSIZE;
  const int context_size = sizeof(TWOFISH_context);

  return _gcry_selftest_helper_ctr("TWOFISH", &twofish_setkey,
           &twofish_encrypt, nblocks, blocksize, context_size);
}

/* Run the self-tests for TWOFISH-CBC, tests bulk CBC decryption.
   Returns NULL on success. */
static const char *
selftest_cbc (void)
{
  const int nblocks = 16+2;
  const int blocksize = TWOFISH_BLOCKSIZE;
  const int context_size = sizeof(TWOFISH_context);

  return _gcry_selftest_helper_cbc("TWOFISH", &twofish_setkey,
           &twofish_encrypt, nblocks, blocksize, context_size);
}

/* Run the self-tests for TWOFISH-CFB, tests bulk CBC decryption.
   Returns NULL on success. */
static const char *
selftest_cfb (void)
{
  const int nblocks = 16+2;
  const int blocksize = TWOFISH_BLOCKSIZE;
  const int context_size = sizeof(TWOFISH_context);

  return _gcry_selftest_helper_cfb("TWOFISH", &twofish_setkey,
           &twofish_encrypt, nblocks, blocksize, context_size);
}


/* Test a single encryption and decryption with each key size. */

static const char*
selftest (void)
{
  TWOFISH_context ctx; /* Expanded key. */
  byte scratch[16];    /* Encryption/decryption result buffer. */
  cipher_bulk_ops_t bulk_ops;
  const char *r;

  /* Test vectors for single encryption/decryption.  Note that I am using
   * the vectors from the Twofish paper's "known answer test", I=3 for
   * 128-bit and I=4 for 256-bit, instead of the all-0 vectors from the
   * "intermediate value test", because an all-0 key would trigger all the
   * special cases in the RS matrix multiply, leaving the math untested. */
  static  byte plaintext[16] = {
    0xD4, 0x91, 0xDB, 0x16, 0xE7, 0xB1, 0xC3, 0x9E,
    0x86, 0xCB, 0x08, 0x6B, 0x78, 0x9F, 0x54, 0x19
  };
  static byte key[16] = {
    0x9F, 0x58, 0x9F, 0x5C, 0xF6, 0x12, 0x2C, 0x32,
    0xB6, 0xBF, 0xEC, 0x2F, 0x2A, 0xE8, 0xC3, 0x5A
  };
  static const byte ciphertext[16] = {
    0x01, 0x9F, 0x98, 0x09, 0xDE, 0x17, 0x11, 0x85,
    0x8F, 0xAA, 0xC3, 0xA3, 0xBA, 0x20, 0xFB, 0xC3
  };
  static byte plaintext_256[16] = {
    0x90, 0xAF, 0xE9, 0x1B, 0xB2, 0x88, 0x54, 0x4F,
    0x2C, 0x32, 0xDC, 0x23, 0x9B, 0x26, 0x35, 0xE6
  };
  static byte key_256[32] = {
    0xD4, 0x3B, 0xB7, 0x55, 0x6E, 0xA3, 0x2E, 0x46,
    0xF2, 0xA2, 0x82, 0xB7, 0xD4, 0x5B, 0x4E, 0x0D,
    0x57, 0xFF, 0x73, 0x9D, 0x4D, 0xC9, 0x2C, 0x1B,
    0xD7, 0xFC, 0x01, 0x70, 0x0C, 0xC8, 0x21, 0x6F
  };
  static const byte ciphertext_256[16] = {
    0x6C, 0xB4, 0x56, 0x1C, 0x40, 0xBF, 0x0A, 0x97,
    0x05, 0x93, 0x1C, 0xB6, 0xD4, 0x08, 0xE7, 0xFA
  };

  twofish_setkey (&ctx, key, sizeof(key), &bulk_ops);
  twofish_encrypt (&ctx, scratch, plaintext);
  if (memcmp (scratch, ciphertext, sizeof (ciphertext)))
    return "Twofish-128 test encryption failed.";
  twofish_decrypt (&ctx, scratch, scratch);
  if (memcmp (scratch, plaintext, sizeof (plaintext)))
    return "Twofish-128 test decryption failed.";

  twofish_setkey (&ctx, key_256, sizeof(key_256), &bulk_ops);
  twofish_encrypt (&ctx, scratch, plaintext_256);
  if (memcmp (scratch, ciphertext_256, sizeof (ciphertext_256)))
    return "Twofish-256 test encryption failed.";
  twofish_decrypt (&ctx, scratch, scratch);
  if (memcmp (scratch, plaintext_256, sizeof (plaintext_256)))
    return "Twofish-256 test decryption failed.";

  if ((r = selftest_ctr()) != NULL)
    return r;
  if ((r = selftest_cbc()) != NULL)
    return r;
  if ((r = selftest_cfb()) != NULL)
    return r;

  return NULL;
}

/* More complete test program.	This does 1000 encryptions and decryptions
 * with each of 250 128-bit keys and 2000 encryptions and decryptions with
 * each of 125 256-bit keys, using a feedback scheme similar to a Feistel
 * cipher, so as to be sure of testing all the table entries pretty
 * thoroughly.	We keep changing the keys so as to get a more meaningful
 * performance number, since the key setup is non-trivial for Twofish. */

#ifdef TEST

#include <stdio.h>
#include <string.h>
#include <time.h>

int
main()
{
  TWOFISH_context ctx;     /* Expanded key. */
  int i, j;                /* Loop counters. */
  cipher_bulk_ops_t bulk_ops;

  const char *encrypt_msg; /* Message to print regarding encryption test;
                            * the printf is done outside the loop to avoid
                            * stuffing up the timing. */
  clock_t timer; /* For computing elapsed time. */

  /* Test buffer. */
  byte buffer[4][16] = {
    {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
     0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF},
    {0x0F, 0x1E, 0x2D, 0x3C, 0x4B, 0x5A, 0x69, 0x78,
     0x87, 0x96, 0xA5, 0xB4, 0xC3, 0xD2 ,0xE1, 0xF0},
    {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF,
     0xFE, 0xDC, 0xBA, 0x98, 0x76, 0x54 ,0x32, 0x10},
    {0x01, 0x23, 0x45, 0x67, 0x76, 0x54 ,0x32, 0x10,
     0x89, 0xAB, 0xCD, 0xEF, 0xFE, 0xDC, 0xBA, 0x98}
  };

  /* Expected outputs for the million-operation test */
  static const byte test_encrypt[4][16] = {
    {0xC8, 0x23, 0xB8, 0xB7, 0x6B, 0xFE, 0x91, 0x13,
     0x2F, 0xA7, 0x5E, 0xE6, 0x94, 0x77, 0x6F, 0x6B},
    {0x90, 0x36, 0xD8, 0x29, 0xD5, 0x96, 0xC2, 0x8E,
     0xE4, 0xFF, 0x76, 0xBC, 0xE5, 0x77, 0x88, 0x27},
    {0xB8, 0x78, 0x69, 0xAF, 0x42, 0x8B, 0x48, 0x64,
     0xF7, 0xE9, 0xF3, 0x9C, 0x42, 0x18, 0x7B, 0x73},
    {0x7A, 0x88, 0xFB, 0xEB, 0x90, 0xA4, 0xB4, 0xA8,
     0x43, 0xA3, 0x1D, 0xF1, 0x26, 0xC4, 0x53, 0x57}
  };
  static const byte test_decrypt[4][16] = {
    {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
     0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF},
    {0x0F, 0x1E, 0x2D, 0x3C, 0x4B, 0x5A, 0x69, 0x78,
     0x87, 0x96, 0xA5, 0xB4, 0xC3, 0xD2 ,0xE1, 0xF0},
    {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF,
     0xFE, 0xDC, 0xBA, 0x98, 0x76, 0x54 ,0x32, 0x10},
    {0x01, 0x23, 0x45, 0x67, 0x76, 0x54 ,0x32, 0x10,
     0x89, 0xAB, 0xCD, 0xEF, 0xFE, 0xDC, 0xBA, 0x98}
  };

  /* Start the timer ticking. */
  timer = clock ();

  /* Encryption test. */
  for (i = 0; i < 125; i++)
    {
      twofish_setkey (&ctx, buffer[0], sizeof (buffer[0]), &bulk_ops);
      for (j = 0; j < 1000; j++)
        twofish_encrypt (&ctx, buffer[2], buffer[2]);
      twofish_setkey (&ctx, buffer[1], sizeof (buffer[1]), &bulk_ops);
      for (j = 0; j < 1000; j++)
        twofish_encrypt (&ctx, buffer[3], buffer[3]);
      twofish_setkey (&ctx, buffer[2], sizeof (buffer[2])*2, &bulk_ops);
      for (j = 0; j < 1000; j++) {
        twofish_encrypt (&ctx, buffer[0], buffer[0]);
        twofish_encrypt (&ctx, buffer[1], buffer[1]);
      }
    }
  encrypt_msg = memcmp (buffer, test_encrypt, sizeof (test_encrypt)) ?
    "encryption failure!\n" : "encryption OK!\n";

  /* Decryption test. */
  for (i = 0; i < 125; i++)
    {
      twofish_setkey (&ctx, buffer[2], sizeof (buffer[2])*2, &bulk_ops);
      for (j = 0; j < 1000; j++) {
        twofish_decrypt (&ctx, buffer[0], buffer[0]);
        twofish_decrypt (&ctx, buffer[1], buffer[1]);
      }
      twofish_setkey (&ctx, buffer[1], sizeof (buffer[1]), &bulk_ops);
      for (j = 0; j < 1000; j++)
        twofish_decrypt (&ctx, buffer[3], buffer[3]);
      twofish_setkey (&ctx, buffer[0], sizeof (buffer[0]), &bulk_ops);
      for (j = 0; j < 1000; j++)
        twofish_decrypt (&ctx, buffer[2], buffer[2]);
    }

  /* Stop the timer, and print results. */
  timer = clock () - timer;
  printf (encrypt_msg);
  printf (memcmp (buffer, test_decrypt, sizeof (test_decrypt)) ?
          "decryption failure!\n" : "decryption OK!\n");
  printf ("elapsed time: %.1f s.\n", (float) timer / CLOCKS_PER_SEC);

  return 0;
}

#endif /* TEST */



gcry_cipher_spec_t _gcry_cipher_spec_twofish =
  {
    GCRY_CIPHER_TWOFISH, {0, 0},
    "TWOFISH", NULL, NULL, 16, 256, sizeof (TWOFISH_context),
    twofish_setkey, twofish_encrypt, twofish_decrypt
  };

gcry_cipher_spec_t _gcry_cipher_spec_twofish128 =
  {
    GCRY_CIPHER_TWOFISH128, {0, 0},
    "TWOFISH128", NULL, NULL, 16, 128, sizeof (TWOFISH_context),
    twofish_setkey, twofish_encrypt, twofish_decrypt
  };