aboutsummaryrefslogtreecommitdiffstats
path: root/src/lib/ffi/ffi.h
blob: f140f617aaff817e256c4a4b6e4346ac4abd7898 (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
/*
* FFI (C89 API)
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_FFI_H_
#define BOTAN_FFI_H_

#ifdef __cplusplus
extern "C" {
#endif

/*
This header exports some of botan's functionality via a C89 interface. This API
is uesd by the Python, OCaml, Rust and Ruby bindings via those languages
respective ctypes/FFI libraries.

The API is intended to be as easy as possible to call from other
languages, which often have easy ways to call C, because C. But some C
code is easier to deal with than others, so to make things easy this
API follows a few simple rules:

- All interactions are via pointers to opaque structs. No need to worry about
  structure padding issues and the like.

- All functions return an int error code (except the version calls, which are
  assumed to always have something to say).

- Use simple types: size_t for lengths, const char* NULL terminated strings,
  uint8_t for binary.

- No ownership of memory transfers across the API boundary. The API will
  consume data from const pointers, and will produce output by writing to
  buffers provided by (and allocated by) the caller.

- If exporting a value (a string or a blob) the function takes a pointer to the
  output array and a read/write pointer to the length. If the length is insufficient, an
  error is returned. So passing nullptr/0 allows querying the final value.

  Note this does not apply to all functions, like `botan_hash_final`
  which is not idempotent and are documented specially. But it's a
  general theory of operation.

 TODO:
 - Doxygen comments for all functions/params
 - TLS
*/

#include <botan/build.h>
#include <stdint.h>
#include <stddef.h>

/**
* Error codes
*
* If you add a new value here be sure to also add it in
* botan_error_description
*/
enum BOTAN_FFI_ERROR {
   BOTAN_FFI_SUCCESS = 0,
   BOTAN_FFI_INVALID_VERIFIER = 1,

   BOTAN_FFI_ERROR_INVALID_INPUT = -1,
   BOTAN_FFI_ERROR_BAD_MAC = -2,

   BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE = -10,

   BOTAN_FFI_ERROR_EXCEPTION_THROWN = -20,
   BOTAN_FFI_ERROR_OUT_OF_MEMORY = -21,
   BOTAN_FFI_ERROR_SYSTEM_ERROR = -22,
   BOTAN_FFI_ERROR_INTERNAL_ERROR = -23,

   BOTAN_FFI_ERROR_BAD_FLAG = -30,
   BOTAN_FFI_ERROR_NULL_POINTER = -31,
   BOTAN_FFI_ERROR_BAD_PARAMETER = -32,
   BOTAN_FFI_ERROR_KEY_NOT_SET = -33,
   BOTAN_FFI_ERROR_INVALID_KEY_LENGTH = -34,
   BOTAN_FFI_ERROR_INVALID_OBJECT_STATE = -35,

   BOTAN_FFI_ERROR_NOT_IMPLEMENTED = -40,
   BOTAN_FFI_ERROR_INVALID_OBJECT = -50,

   BOTAN_FFI_ERROR_TLS_ERROR = -75,
   BOTAN_FFI_ERROR_HTTP_ERROR = -76,

   BOTAN_FFI_ERROR_UNKNOWN_ERROR = -100,
};

/**
* Convert an error code into a string. Returns "Unknown error"
* if the error code is not a known one.
*/
BOTAN_PUBLIC_API(2,8) const char* botan_error_description(int err);

/**
* Return the version of the currently supported FFI API. This is
* expressed in the form YYYYMMDD of the release date of this version
* of the API.
*/
BOTAN_PUBLIC_API(2,0) uint32_t botan_ffi_api_version(void);

/**
* Return 0 (ok) if the version given is one this library supports.
* botan_ffi_supports_api(botan_ffi_api_version()) will always return 0.
*/
BOTAN_PUBLIC_API(2,0) int botan_ffi_supports_api(uint32_t api_version);

/**
* Return a free-form version string, e.g., 2.0.0
*/
BOTAN_PUBLIC_API(2,0) const char* botan_version_string(void);

/**
* Return the major version of the library
*/
BOTAN_PUBLIC_API(2,0) uint32_t botan_version_major(void);

/**
* Return the minor version of the library
*/
BOTAN_PUBLIC_API(2,0) uint32_t botan_version_minor(void);

/**
* Return the patch version of the library
*/
BOTAN_PUBLIC_API(2,0) uint32_t botan_version_patch(void);

/**
* Return the date this version was released as
* an integer, or 0 if an unreleased version
*/
BOTAN_PUBLIC_API(2,0) uint32_t botan_version_datestamp(void);

/**
* Returns 0 if x[0..len] == y[0..len], or otherwise -1
*/
BOTAN_PUBLIC_API(2,3) int botan_constant_time_compare(const uint8_t* x, const uint8_t* y, size_t len);

/**
* Deprecated equivalent to botan_constant_time_compare
*/
BOTAN_PUBLIC_API(2,0) int botan_same_mem(const uint8_t* x, const uint8_t* y, size_t len);

/**
* Clear out memory using a system specific approach to bypass elision by the
* compiler (currently using RtlSecureZeroMemory or tricks with volatile pointers).
*/
BOTAN_PUBLIC_API(2,2) int botan_scrub_mem(void* mem, size_t bytes);

#define BOTAN_FFI_HEX_LOWER_CASE 1

/**
* Perform hex encoding
* @param x is some binary data
* @param len length of x in bytes
* @param out an array of at least x*2 bytes
* @param flags flags out be upper or lower case?
* @return 0 on success, 1 on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_hex_encode(const uint8_t* x, size_t len, char* out, uint32_t flags);

/**
* Perform hex decoding
* @param hex_str a string of hex chars (whitespace is ignored)
* @param in_len the length of hex_str
* @param out the output buffer should be at least strlen(hex_str)/2 bytes
* @param out_len the size of out
*/
BOTAN_PUBLIC_API(2,3) int botan_hex_decode(const char* hex_str, size_t in_len, uint8_t* out, size_t* out_len);

/**
* Perform base64 encoding
*/
BOTAN_PUBLIC_API(2,3) int botan_base64_encode(const uint8_t* x, size_t len, char* out, size_t* out_len);


/**
* Perform base64 decoding
*/
BOTAN_PUBLIC_API(2,3) int botan_base64_decode(const char* base64_str, size_t in_len,
                                              uint8_t* out, size_t* out_len);

/**
* RNG type
*/
typedef struct botan_rng_struct* botan_rng_t;

/**
* Initialize a random number generator object
* @param rng rng object
* @param rng_type type of the rng, possible values:
*    "system": system RNG
*    "user": userspace RNG
*    "user-threadsafe": userspace RNG, with internal locking
*    "rdrand": directly read RDRAND
* Set rng_type to null to let the library choose some default.
*/
BOTAN_PUBLIC_API(2,0) int botan_rng_init(botan_rng_t* rng, const char* rng_type);

/**
* Get random bytes from a random number generator
* @param rng rng object
* @param out output buffer of size out_len
* @param out_len number of requested bytes
* @return 0 on success, negative on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_rng_get(botan_rng_t rng, uint8_t* out, size_t out_len);

/**
* Reseed a random number generator
* Uses the System_RNG as a seed generator.
*
* @param rng rng object
* @param bits number of bits to to reseed with
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_rng_reseed(botan_rng_t rng, size_t bits);

/**
* Reseed a random number generator
*
* @param rng rng object
* @param source_rng the rng that will be read from
* @param bits number of bits to to reseed with
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,8) int botan_rng_reseed_from_rng(botan_rng_t rng,
                                                    botan_rng_t source_rng,
                                                    size_t bits);

/**
* Add some seed material to a random number generator
*
* @param rng rng object
* @param entropy the data to add
* @param entropy_len length of entropy buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,8) int botan_rng_add_entropy(botan_rng_t rng,
                                                const uint8_t* entropy,
                                                size_t entropy_len);

/**
* Frees all resources of the random number generator object
* @param rng rng object
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_rng_destroy(botan_rng_t rng);

/*
* Hash type
*/
typedef struct botan_hash_struct* botan_hash_t;

/**
* Initialize a hash function object
* @param hash hash object
* @param hash_name name of the hash function, e.g., "SHA-384"
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return BOTAN_FFI_ERROR_BAD_FLAG
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_init(botan_hash_t* hash, const char* hash_name, uint32_t flags);

/**
* Copy the state of a hash function object
* @param dest destination hash object
* @param source source hash object
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,2) int botan_hash_copy_state(botan_hash_t *dest, const botan_hash_t source);

/**
* Writes the output length of the hash function to *output_length
* @param hash hash object
* @param output_length output buffer to hold the hash function output length
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_output_length(botan_hash_t hash, size_t* output_length);

/**
* Writes the block size of the hash function to *block_size
* @param hash hash object
* @param block_size output buffer to hold the hash function output length
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,2) int botan_hash_block_size(botan_hash_t hash, size_t* block_size);

/**
* Send more input to the hash function
* @param hash hash object
* @param in input buffer
* @param in_len number of bytes to read from the input buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_update(botan_hash_t hash, const uint8_t* in, size_t in_len);

/**
* Finalizes the hash computation and writes the output to
* out[0:botan_hash_output_length()] then reinitializes for computing
* another digest as if botan_hash_clear had been called.
* @param hash hash object
* @param out output buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_final(botan_hash_t hash, uint8_t out[]);

/**
* Reinitializes the state of the hash computation. A hash can
* be computed (with update/final) immediately.
* @param hash hash object
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_clear(botan_hash_t hash);

/**
* Frees all resources of the hash object
* @param hash hash object
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_hash_destroy(botan_hash_t hash);

/**
* Get the name of this hash function
* @param hash the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_PUBLIC_API(2,8) int botan_hash_name(botan_hash_t hash, char* name, size_t* name_len);

/*
* Message Authentication type
*/
typedef struct botan_mac_struct* botan_mac_t;

/**
* Initialize a message authentication code object
* @param mac mac object
* @param mac_name name of the hash function, e.g., "HMAC(SHA-384)"
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return a negative value (error code)
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_init(botan_mac_t* mac, const char* mac_name, uint32_t flags);

/**
* Writes the output length of the message authentication code to *output_length
* @param mac mac object
* @param output_length output buffer to hold the MAC output length
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_output_length(botan_mac_t mac, size_t* output_length);

/**
* Sets the key on the MAC
* @param mac mac object
* @param key buffer holding the key
* @param key_len size of the key buffer in bytes
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_set_key(botan_mac_t mac, const uint8_t* key, size_t key_len);

/**
* Send more input to the message authentication code
* @param mac mac object
* @param buf input buffer
* @param len number of bytes to read from the input buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_update(botan_mac_t mac, const uint8_t* buf, size_t len);

/**
* Finalizes the MAC computation and writes the output to
* out[0:botan_mac_output_length()] then reinitializes for computing
* another MAC as if botan_mac_clear had been called.
* @param mac mac object
* @param out output buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_final(botan_mac_t mac, uint8_t out[]);

/**
* Reinitializes the state of the MAC computation. A MAC can
* be computed (with update/final) immediately.
* @param mac mac object
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_clear(botan_mac_t mac);

/**
* Get the name of this MAC
* @param mac the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_PUBLIC_API(2,8) int botan_mac_name(botan_mac_t mac, char* name, size_t* name_len);

/**
* Get the key length limits of this auth code
* @param mac the object to read
* @param out_minimum_keylength if non-NULL, will be set to minimum keylength of MAC
* @param out_maximum_keylength if non-NULL, will be set to maximum keylength of MAC
* @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
*/
BOTAN_PUBLIC_API(2,8) int botan_mac_get_keyspec(botan_mac_t mac,
                                                 size_t* out_minimum_keylength,
                                                 size_t* out_maximum_keylength,
                                                 size_t* out_keylength_modulo);

/**
* Frees all resources of the MAC object
* @param mac mac object
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_mac_destroy(botan_mac_t mac);

/*
* Cipher modes
*/
typedef struct botan_cipher_struct* botan_cipher_t;

#define BOTAN_CIPHER_INIT_FLAG_MASK_DIRECTION 1
#define BOTAN_CIPHER_INIT_FLAG_ENCRYPT 0
#define BOTAN_CIPHER_INIT_FLAG_DECRYPT 1

/**
* Initialize a cipher object
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_init(botan_cipher_t* cipher, const char* name, uint32_t flags);

/**
* Return the name of the cipher object
*/
BOTAN_PUBLIC_API(2,8) int botan_cipher_name(botan_cipher_t cipher, char* name, size_t* name_len);

/**
* Return the output length of this cipher, for a particular input length.
*/
BOTAN_PUBLIC_API(2,8) int botan_cipher_output_length(botan_cipher_t cipher, size_t in_len, size_t* out_len);

/**
* Return if the specified nonce length is valid for this cipher
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_valid_nonce_length(botan_cipher_t cipher, size_t nl);

/**
* Get the tag length of the cipher (0 for non-AEAD modes)
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_get_tag_length(botan_cipher_t cipher, size_t* tag_size);

/**
* Get the default nonce length of this cipher
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_get_default_nonce_length(botan_cipher_t cipher, size_t* nl);

/**
* Return the update granularity of the cipher; botan_cipher_update must be
* called with blocks of this size, except for the final.
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_get_update_granularity(botan_cipher_t cipher, size_t* ug);

/**
* Get information about the key lengths. Prefer botan_cipher_get_keyspec
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_query_keylen(botan_cipher_t,
                                        size_t* out_minimum_keylength,
                                        size_t* out_maximum_keylength);

/**
* Get information about the supported key lengths.
*/
BOTAN_PUBLIC_API(2,8) int botan_cipher_get_keyspec(botan_cipher_t,
                                                   size_t* min_keylen,
                                                   size_t* max_keylen,
                                                   size_t* mod_keylen);

/**
* Set the key for this cipher object
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_set_key(botan_cipher_t cipher,
                                               const uint8_t* key, size_t key_len);

/**
* Reset the message specific state for this cipher.
* Without resetting the keys, this resets the nonce, and any state
* associated with any message bits that have been processed so far.
*
* It is conceptually equivalent to calling botan_cipher_clear followed
* by botan_cipher_set_key with the original key.
*/
BOTAN_PUBLIC_API(2,8) int botan_cipher_reset(botan_cipher_t cipher);

/**
* Set the associated data. Will fail if cipher is not an AEAD
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_set_associated_data(botan_cipher_t cipher,
                                               const uint8_t* ad, size_t ad_len);

/**
* Begin processing a new message using the provided nonce
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_start(botan_cipher_t cipher,
                                 const uint8_t* nonce, size_t nonce_len);

#define BOTAN_CIPHER_UPDATE_FLAG_FINAL (1U << 0)

/**
* Encrypt some data
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_update(botan_cipher_t cipher,
                                  uint32_t flags,
                                  uint8_t output[],
                                  size_t output_size,
                                  size_t* output_written,
                                  const uint8_t input_bytes[],
                                  size_t input_size,
                                  size_t* input_consumed);

/**
* Reset the key, nonce, AD and all other state on this cipher object
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_clear(botan_cipher_t hash);

/**
* Destroy the cipher object
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_cipher_destroy(botan_cipher_t cipher);

/*
* Derive a key from a passphrase for a number of iterations
* @param pbkdf_algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)"
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
* @return 0 on success, a negative value on failure
*
* Deprecated: use
*  botan_pwdhash(pbkdf_algo, iterations, 0, 0, out, out_len,
*                passphrase, 0, salt, salt_len);
*/
BOTAN_PUBLIC_API(2,0) int
BOTAN_DEPRECATED("Use botan_pwdhash")
botan_pbkdf(const char* pbkdf_algo,
            uint8_t out[], size_t out_len,
            const char* passphrase,
            const uint8_t salt[], size_t salt_len,
            size_t iterations);

/**
* Derive a key from a passphrase, running until msec time has elapsed.
* @param pbkdf_algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)"
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param milliseconds_to_run if iterations is zero, then instead the PBKDF is
*        run until milliseconds_to_run milliseconds has passed
* @param out_iterations_used set to the number iterations executed
* @return 0 on success, a negative value on failure
*
* Deprecated: use
*
* botan_pwdhash_timed(pbkdf_algo,
*                     static_cast<uint32_t>(ms_to_run),
*                     iterations_used,
*                     nullptr,
*                     nullptr,
*                     out, out_len,
*                     password, 0,
*                     salt, salt_len);
*/
BOTAN_PUBLIC_API(2,0) int botan_pbkdf_timed(const char* pbkdf_algo,
                                uint8_t out[], size_t out_len,
                                const char* passphrase,
                                const uint8_t salt[], size_t salt_len,
                                size_t milliseconds_to_run,
                                size_t* out_iterations_used);


/*
* Derive a key from a passphrase
* @param algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)" or "Scrypt"
* @param param1 the first PBKDF algorithm parameter
* @param param2 the second PBKDF algorithm parameter (may be zero if unneeded)
* @param param3 the third PBKDF algorithm parameter (may be zero if unneeded)
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param passphrase_len if > 0, specifies length of password. If len == 0, then
*        strlen will be called on passphrase to compute the length.
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @return 0 on success, a negative value on failure
*/
int BOTAN_PUBLIC_API(2,8) botan_pwdhash(
   const char* algo,
   size_t param1,
   size_t param2,
   size_t param3,
   uint8_t out[],
   size_t out_len,
   const char* passphrase,
   size_t passphrase_len,
   const uint8_t salt[],
   size_t salt_len);

/*
* Derive a key from a passphrase
* @param pbkdf_algo PBKDF algorithm, e.g., "Scrypt" or "PBKDF2(SHA-256)"
* @param msec the desired runtime in milliseconds
* @param param1 will be set to the first password hash parameter
* @param param2 will be set to the second password hash parameter
* @param param3 will be set to the third password hash parameter
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param passphrase_len if > 0, specifies length of password. If len == 0, then
*        strlen will be called on passphrase to compute the length.
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @return 0 on success, a negative value on failure
*/
int BOTAN_PUBLIC_API(2,8) botan_pwdhash_timed(
   const char* algo,
   uint32_t msec,
   size_t* param1,
   size_t* param2,
   size_t* param3,
   uint8_t out[],
   size_t out_len,
   const char* passphrase,
   size_t passphrase_len,
   const uint8_t salt[],
   size_t salt_len);

/**
* Derive a key using scrypt
* Deprecated; use
* botan_pwdhash("Scrypt", N, r, p, out, out_len, password, 0, salt, salt_len);
*/
BOTAN_PUBLIC_API(2,8) int
BOTAN_DEPRECATED("Use botan_pwdhash")
botan_scrypt(uint8_t out[], size_t out_len,
             const char* passphrase,
             const uint8_t salt[], size_t salt_len,
             size_t N, size_t r, size_t p);

/**
* Derive a key
* @param kdf_algo KDF algorithm, e.g., "SP800-56C"
* @param out buffer holding the derived key, must be of length out_len
* @param out_len the desired output length in bytes
* @param secret the secret input
* @param secret_len size of secret in bytes
* @param salt a diversifier
* @param salt_len size of salt in bytes
* @param label purpose for the derived keying material
* @param label_len size of label in bytes
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_kdf(const char* kdf_algo,
                        uint8_t out[], size_t out_len,
                        const uint8_t secret[], size_t secret_len,
                        const uint8_t salt[], size_t salt_len,
                        const uint8_t label[], size_t label_len);

/*
* Raw Block Cipher (PRP) interface
*/
typedef struct botan_block_cipher_struct* botan_block_cipher_t;

/**
* Initialize a block cipher object
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_init(botan_block_cipher_t* bc,
                                                  const char* cipher_name);

/**
* Destroy a block cipher object
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_destroy(botan_block_cipher_t bc);

/**
* Reinitializes the block cipher
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_clear(botan_block_cipher_t bc);

/**
* Set the key for a block cipher instance
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_set_key(botan_block_cipher_t bc,
                                                     const uint8_t key[], size_t len);

/**
* Return the positive block size of this block cipher, or negative to
* indicate an error
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_block_size(botan_block_cipher_t bc);

/**
* Encrypt one or more blocks with the cipher
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_encrypt_blocks(botan_block_cipher_t bc,
                                                            const uint8_t in[],
                                                            uint8_t out[],
                                                            size_t blocks);

/**
* Decrypt one or more blocks with the cipher
*/
BOTAN_PUBLIC_API(2,1) int botan_block_cipher_decrypt_blocks(botan_block_cipher_t bc,
                                                            const uint8_t in[],
                                                            uint8_t out[],
                                                            size_t blocks);

/**
* Get the name of this block cipher
* @param cipher the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_PUBLIC_API(2,8) int botan_block_cipher_name(botan_block_cipher_t cipher,
                                                  char* name, size_t* name_len);


/**
* Get the key length limits of this block cipher
* @param cipher the object to read
* @param out_minimum_keylength if non-NULL, will be set to minimum keylength of cipher
* @param out_maximum_keylength if non-NULL, will be set to maximum keylength of cipher
* @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
*/
BOTAN_PUBLIC_API(2,8) int botan_block_cipher_get_keyspec(botan_block_cipher_t cipher,
                                                         size_t* out_minimum_keylength,
                                                         size_t* out_maximum_keylength,
                                                         size_t* out_keylength_modulo);

/*
* Multiple precision integers (MPI)
*/
typedef struct botan_mp_struct* botan_mp_t;

/**
* Initialize an MPI
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_init(botan_mp_t* mp);

/**
* Destroy (deallocate) an MPI
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_destroy(botan_mp_t mp);

/**
* Convert the MPI to a hex string. Writes botan_mp_num_bytes(mp)*2 + 1 bytes
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_to_hex(const botan_mp_t mp, char* out);

/**
* Convert the MPI to a string. Currently base == 10 and base == 16 are supported.
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_to_str(const botan_mp_t mp, uint8_t base, char* out, size_t* out_len);

/**
* Set the MPI to zero
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_clear(botan_mp_t mp);

/**
* Set the MPI value from an int
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_set_from_int(botan_mp_t mp, int initial_value);

/**
* Set the MPI value from another MP object
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_set_from_mp(botan_mp_t dest, const botan_mp_t source);

/**
* Set the MPI value from a string
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_set_from_str(botan_mp_t dest, const char* str);

/**
* Set the MPI value from a string with arbitrary radix.
* For arbitrary being 10 or 16.
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_set_from_radix_str(botan_mp_t dest, const char* str, size_t radix);

/**
* Return the number of significant bits in the MPI
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_num_bits(const botan_mp_t n, size_t* bits);

/**
* Return the number of significant bytes in the MPI
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_num_bytes(const botan_mp_t n, size_t* bytes);

/*
* Convert the MPI to a big-endian binary string. Writes botan_mp_num_bytes to vec
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_to_bin(const botan_mp_t mp, uint8_t vec[]);

/*
* Set an MP to the big-endian binary value
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_from_bin(const botan_mp_t mp, const uint8_t vec[], size_t vec_len);

/*
* Convert the MPI to a uint32_t, if possible. Fails if MPI is negative or too large.
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_to_uint32(const botan_mp_t mp, uint32_t* val);

/**
* This function should have been named mp_is_non_negative. Returns 1
* iff mp is greater than *or equal to* zero. Use botan_mp_is_negative
* to detect negative numbers, botan_mp_is_zero to check for zero.
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_is_positive(const botan_mp_t mp);

/**
* Return 1 iff mp is less than 0
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_is_negative(const botan_mp_t mp);

BOTAN_PUBLIC_API(2,1) int botan_mp_flip_sign(botan_mp_t mp);

BOTAN_PUBLIC_API(2,1) int botan_mp_is_zero(const botan_mp_t mp);

BOTAN_PUBLIC_API(2,1) BOTAN_DEPRECATED("Use botan_mp_get_bit(0)")
int botan_mp_is_odd(const botan_mp_t mp);
BOTAN_PUBLIC_API(2,1) BOTAN_DEPRECATED("Use botan_mp_get_bit(0)")
int botan_mp_is_even(const botan_mp_t mp);

BOTAN_PUBLIC_API(2,8) int botan_mp_add_u32(botan_mp_t result, const botan_mp_t x, uint32_t y);
BOTAN_PUBLIC_API(2,8) int botan_mp_sub_u32(botan_mp_t result, const botan_mp_t x, uint32_t y);

BOTAN_PUBLIC_API(2,1) int botan_mp_add(botan_mp_t result, const botan_mp_t x, const botan_mp_t y);
BOTAN_PUBLIC_API(2,1) int botan_mp_sub(botan_mp_t result, const botan_mp_t x, const botan_mp_t y);
BOTAN_PUBLIC_API(2,1) int botan_mp_mul(botan_mp_t result, const botan_mp_t x, const botan_mp_t y);

BOTAN_PUBLIC_API(2,1) int botan_mp_div(botan_mp_t quotient,
                                       botan_mp_t remainder,
                                       const botan_mp_t x, const botan_mp_t y);

BOTAN_PUBLIC_API(2,1) int botan_mp_mod_mul(botan_mp_t result, const botan_mp_t x,
                                           const botan_mp_t y, const botan_mp_t mod);

/*
* Returns 0 if x != y
* Returns 1 if x == y
* Returns negative number on error
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_equal(const botan_mp_t x, const botan_mp_t y);

/*
* Sets *result to comparison result:
* -1 if x < y, 0 if x == y, 1 if x > y
* Returns negative number on error or zero on success
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_cmp(int* result, const botan_mp_t x, const botan_mp_t y);

/*
* Swap two botan_mp_t
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_swap(botan_mp_t x, botan_mp_t y);

/* Return (base^exponent) % modulus */
BOTAN_PUBLIC_API(2,1) int botan_mp_powmod(botan_mp_t out, const botan_mp_t base, const botan_mp_t exponent, const botan_mp_t modulus);

BOTAN_PUBLIC_API(2,1) int botan_mp_lshift(botan_mp_t out, const botan_mp_t in, size_t shift);
BOTAN_PUBLIC_API(2,1) int botan_mp_rshift(botan_mp_t out, const botan_mp_t in, size_t shift);

BOTAN_PUBLIC_API(2,1) int botan_mp_mod_inverse(botan_mp_t out, const botan_mp_t in, const botan_mp_t modulus);

BOTAN_PUBLIC_API(2,1) int botan_mp_rand_bits(botan_mp_t rand_out, botan_rng_t rng, size_t bits);

BOTAN_PUBLIC_API(2,1) int botan_mp_rand_range(botan_mp_t rand_out, botan_rng_t rng,
                                  const botan_mp_t lower_bound, const botan_mp_t upper_bound);

BOTAN_PUBLIC_API(2,1) int botan_mp_gcd(botan_mp_t out, const botan_mp_t x, const botan_mp_t y);

/**
* Returns 0 if n is not prime
* Returns 1 if n is prime
* Returns negative number on error
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_is_prime(const botan_mp_t n, botan_rng_t rng, size_t test_prob);

/**
* Returns 0 if specified bit of n is not set
* Returns 1 if specified bit of n is set
* Returns negative number on error
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_get_bit(const botan_mp_t n, size_t bit);

/**
* Set the specified bit
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_set_bit(botan_mp_t n, size_t bit);

/**
* Clear the specified bit
*/
BOTAN_PUBLIC_API(2,1) int botan_mp_clear_bit(botan_mp_t n, size_t bit);

/* Bcrypt password hashing */

/**
* Create a password hash using Bcrypt
* @param out buffer holding the password hash, should be of length 64 bytes
* @param out_len the desired output length in bytes
* @param password the password
* @param rng a random number generator
* @param work_factor how much work to do to slow down guessing attacks
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return BOTAN_FFI_ERROR_BAD_FLAG
* @return 0 on success, a negative value on failure

* Output is formatted bcrypt $2a$...
*/
BOTAN_PUBLIC_API(2,0) int botan_bcrypt_generate(uint8_t* out, size_t* out_len,
                                    const char* password,
                                    botan_rng_t rng,
                                    size_t work_factor,
                                    uint32_t flags);

/**
* Check a previously created password hash
* @param pass the password to check against
* @param hash the stored hash to check against
* @return 0 if if this password/hash combination is valid,
*       1 if the combination is not valid (but otherwise well formed),
*       negative on error
*/
BOTAN_PUBLIC_API(2,0) int botan_bcrypt_is_valid(const char* pass, const char* hash);

/*
* Public/private key creation, import, ...
*/
typedef struct botan_privkey_struct* botan_privkey_t;

/**
* Create a new private key
* @param key the new object will be placed here
* @param algo_name something like "RSA" or "ECDSA"
* @param algo_params is specific to the algorithm. For RSA, specifies
*        the modulus bit length. For ECC is the name of the curve.
* @param rng a random number generator
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_create(botan_privkey_t* key,
                                               const char* algo_name,
                                               const char* algo_params,
                                               botan_rng_t rng);

#define BOTAN_CHECK_KEY_EXPENSIVE_TESTS 1

BOTAN_PUBLIC_API(2,0) int botan_privkey_check_key(botan_privkey_t key, botan_rng_t rng, uint32_t flags);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_create")
int botan_privkey_create_rsa(botan_privkey_t* key, botan_rng_t rng, size_t n_bits);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_create")
int botan_privkey_create_ecdsa(botan_privkey_t* key, botan_rng_t rng, const char* params);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_create")
int botan_privkey_create_ecdh(botan_privkey_t* key, botan_rng_t rng, const char* params);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_create")
int botan_privkey_create_mceliece(botan_privkey_t* key, botan_rng_t rng, size_t n, size_t t);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_create")
int botan_privkey_create_dh(botan_privkey_t* key, botan_rng_t rng, const char* param);

/**
 * Generates DSA key pair. Gives to a caller control over key length
 * and order of a subgroup 'q'.
 *
 * @param   key   handler to the resulting key
 * @param   rng   initialized PRNG
 * @param   pbits length of the key in bits. Must be between in range (1024, 3072)
 *          and multiple of 64. Bit size of the prime 'p'
 * @param   qbits order of the subgroup. Must be in range (160, 256) and multiple
 *          of 8
 *
 * @returns BOTAN_FFI_SUCCESS Success, `key' initialized with DSA key
 * @returns BOTAN_FFI_ERROR_NULL_POINTER  either `key' or `rng' is NULL
 * @returns BOTAN_FFI_ERROR_BAD_PARAMETER unexpected value for either `pbits' or
 *          `qbits'
 * @returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED functionality not implemented
 *
*/
BOTAN_PUBLIC_API(2,5) int botan_privkey_create_dsa(
                                botan_privkey_t* key,
                                botan_rng_t rng,
                                size_t pbits,
                                size_t qbits);

/**
 * Generates ElGamal key pair. Caller has a control over key length
 * and order of a subgroup 'q'. Function is able to use two types of
 * primes:
 *    * if pbits-1 == qbits then safe primes are used for key generation
 *    * otherwise generation uses group of prime order
 *
 * @param   key   handler to the resulting key
 * @param   rng   initialized PRNG
 * @param   pbits length of the key in bits. Must be at least 1024
 * @param   qbits order of the subgroup. Must be at least 160
 *
 * @returns BOTAN_FFI_SUCCESS Success, `key' initialized with DSA key
 * @returns BOTAN_FFI_ERROR_NULL_POINTER  either `key' or `rng' is NULL
 * @returns BOTAN_FFI_ERROR_BAD_PARAMETER unexpected value for either `pbits' or
 *          `qbits'
 * @returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED functionality not implemented
 *
*/
BOTAN_PUBLIC_API(2,5) int botan_privkey_create_elgamal(
                            botan_privkey_t* key,
                            botan_rng_t rng,
                            size_t pbits,
                            size_t qbits);

/**
* Input currently assumed to be PKCS #8 structure;
* Set password to NULL to indicate no encryption expected
* Starting in 2.8.0, the rng parameter is unused and may be set to null
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_load(botan_privkey_t* key,
                                             botan_rng_t rng,
                                             const uint8_t bits[], size_t len,
                                             const char* password);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_destroy(botan_privkey_t key);

#define BOTAN_PRIVKEY_EXPORT_FLAG_DER 0
#define BOTAN_PRIVKEY_EXPORT_FLAG_PEM 1

/**
* On input *out_len is number of bytes in out[]
* On output *out_len is number of bytes written (or required)
* If out is not big enough no output is written, *out_len is set and 1 is returned
* Returns 0 on success and sets
* If some other error occurs a negative integer is returned.
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_export(botan_privkey_t key,
                                   uint8_t out[], size_t* out_len,
                                   uint32_t flags);

BOTAN_PUBLIC_API(2,8) int botan_privkey_algo_name(botan_privkey_t key, char out[], size_t* out_len);

/**
* Set encryption_algo to NULL or "" to have the library choose a default (recommended)
*/
BOTAN_DEPRECATED("Use botan_privkey_export_encrypted_pbkdf_{msec,iter}")
BOTAN_PUBLIC_API(2,0) int botan_privkey_export_encrypted(botan_privkey_t key,
                                             uint8_t out[], size_t* out_len,
                                             botan_rng_t rng,
                                             const char* passphrase,
                                             const char* encryption_algo,
                                             uint32_t flags);

/*
* Export a private key, running PBKDF for specified amount of time
* @param key the private key to export
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_export_encrypted_pbkdf_msec(botan_privkey_t key,
                                                        uint8_t out[], size_t* out_len,
                                                        botan_rng_t rng,
                                                        const char* passphrase,
                                                        uint32_t pbkdf_msec_runtime,
                                                        size_t* pbkdf_iterations_out,
                                                        const char* cipher_algo,
                                                        const char* pbkdf_algo,
                                                        uint32_t flags);

/**
* Export a private key using the specified number of iterations.
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_export_encrypted_pbkdf_iter(botan_privkey_t key,
                                                        uint8_t out[], size_t* out_len,
                                                        botan_rng_t rng,
                                                        const char* passphrase,
                                                        size_t pbkdf_iterations,
                                                        const char* cipher_algo,
                                                        const char* pbkdf_algo,
                                                        uint32_t flags);

typedef struct botan_pubkey_struct* botan_pubkey_t;

BOTAN_PUBLIC_API(2,0) int botan_pubkey_load(botan_pubkey_t* key, const uint8_t bits[], size_t len);

BOTAN_PUBLIC_API(2,0) int botan_privkey_export_pubkey(botan_pubkey_t* out, botan_privkey_t in);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_export(botan_pubkey_t key, uint8_t out[], size_t* out_len, uint32_t flags);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_algo_name(botan_pubkey_t key, char out[], size_t* out_len);

/**
* Returns 0 if key is valid, negative if invalid key or some other error
*/
BOTAN_PUBLIC_API(2,0) int botan_pubkey_check_key(botan_pubkey_t key, botan_rng_t rng, uint32_t flags);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_estimated_strength(botan_pubkey_t key, size_t* estimate);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_fingerprint(botan_pubkey_t key, const char* hash,
                                       uint8_t out[], size_t* out_len);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pubkey_destroy(botan_pubkey_t key);

/*
* Get arbitrary named fields from public or privat keys
*/
BOTAN_PUBLIC_API(2,0) int botan_pubkey_get_field(botan_mp_t output,
                                     botan_pubkey_t key,
                                     const char* field_name);

BOTAN_PUBLIC_API(2,0) int botan_privkey_get_field(botan_mp_t output,
                                      botan_privkey_t key,
                                      const char* field_name);

/*
* Algorithm specific key operations: RSA
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_load_rsa(botan_privkey_t* key,
                                     botan_mp_t p,
                                     botan_mp_t q,
                                     botan_mp_t e);

BOTAN_PUBLIC_API(2,8) int botan_privkey_load_rsa_pkcs1(botan_privkey_t* key,
                                                       const uint8_t bits[],
                                                       size_t len);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_rsa_get_p(botan_mp_t p, botan_privkey_t rsa_key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_rsa_get_q(botan_mp_t q, botan_privkey_t rsa_key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_rsa_get_d(botan_mp_t d, botan_privkey_t rsa_key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_rsa_get_n(botan_mp_t n, botan_privkey_t rsa_key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_rsa_get_e(botan_mp_t e, botan_privkey_t rsa_key);

BOTAN_PUBLIC_API(2,8) int botan_privkey_rsa_get_privkey(botan_privkey_t rsa_key,
                                                        uint8_t out[], size_t* out_len,
                                                        uint32_t flags);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_load_rsa(botan_pubkey_t* key,
                                                botan_mp_t n,
                                                botan_mp_t e);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_rsa_get_e(botan_mp_t e, botan_pubkey_t rsa_key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_rsa_get_n(botan_mp_t n, botan_pubkey_t rsa_key);

/*
* Algorithm specific key operations: DSA
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_load_dsa(botan_privkey_t* key,
                                     botan_mp_t p,
                                     botan_mp_t q,
                                     botan_mp_t g,
                                     botan_mp_t x);

BOTAN_PUBLIC_API(2,0) int botan_pubkey_load_dsa(botan_pubkey_t* key,
                                    botan_mp_t p,
                                    botan_mp_t q,
                                    botan_mp_t g,
                                    botan_mp_t y);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_privkey_get_field")
int botan_privkey_dsa_get_x(botan_mp_t n, botan_privkey_t key);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_dsa_get_p(botan_mp_t p, botan_pubkey_t key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_dsa_get_q(botan_mp_t q, botan_pubkey_t key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_dsa_get_g(botan_mp_t d, botan_pubkey_t key);
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Use botan_pubkey_get_field")
int botan_pubkey_dsa_get_y(botan_mp_t y, botan_pubkey_t key);

/*
* Loads Diffie Hellman private key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param x private key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_load_dh(botan_privkey_t* key,
                                         botan_mp_t p,
                                         botan_mp_t g,
                                         botan_mp_t x);
/**
* Loads Diffie Hellman public key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param y public key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_pubkey_load_dh(botan_pubkey_t* key,
                                        botan_mp_t p,
                                        botan_mp_t g,
                                        botan_mp_t y);

/*
* Algorithm specific key operations: ElGamal
*/

/**
* Loads ElGamal public key
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param y public key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_pubkey_load_elgamal(botan_pubkey_t* key,
                                        botan_mp_t p,
                                        botan_mp_t g,
                                        botan_mp_t y);

/**
* Loads ElGamal private key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param x private key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_PUBLIC_API(2,0) int botan_privkey_load_elgamal(botan_privkey_t* key,
                                         botan_mp_t p,
                                         botan_mp_t g,
                                         botan_mp_t x);

/*
* Algorithm specific key operations: Ed25519
*/

BOTAN_PUBLIC_API(2,2) int botan_privkey_load_ed25519(botan_privkey_t* key,
                                         const uint8_t privkey[32]);

BOTAN_PUBLIC_API(2,2) int botan_pubkey_load_ed25519(botan_pubkey_t* key,
                                        const uint8_t pubkey[32]);

BOTAN_PUBLIC_API(2,2) int botan_privkey_ed25519_get_privkey(botan_privkey_t key,
                                                uint8_t output[64]);

BOTAN_PUBLIC_API(2,2) int botan_pubkey_ed25519_get_pubkey(botan_pubkey_t key,
                                              uint8_t pubkey[32]);

/*
* Algorithm specific key operations: X25519
*/

BOTAN_PUBLIC_API(2,8) int botan_privkey_load_x25519(botan_privkey_t* key,
                                                    const uint8_t privkey[32]);

BOTAN_PUBLIC_API(2,8) int botan_pubkey_load_x25519(botan_pubkey_t* key,
                                                   const uint8_t pubkey[32]);

BOTAN_PUBLIC_API(2,8) int botan_privkey_x25519_get_privkey(botan_privkey_t key,
                                                           uint8_t output[32]);

BOTAN_PUBLIC_API(2,8) int botan_pubkey_x25519_get_pubkey(botan_pubkey_t key,
                                                         uint8_t pubkey[32]);

/*
* Algorithm specific key operations: ECDSA and ECDH
*/
BOTAN_PUBLIC_API(2,2)
int botan_privkey_load_ecdsa(botan_privkey_t* key,
                             const botan_mp_t scalar,
                             const char* curve_name);

BOTAN_PUBLIC_API(2,2)
int botan_pubkey_load_ecdsa(botan_pubkey_t* key,
                            const botan_mp_t public_x,
                            const botan_mp_t public_y,
                            const char* curve_name);

BOTAN_PUBLIC_API(2,2)
int botan_pubkey_load_ecdh(botan_pubkey_t* key,
                           const botan_mp_t public_x,
                           const botan_mp_t public_y,
                           const char* curve_name);

BOTAN_PUBLIC_API(2,2)
int botan_privkey_load_ecdh(botan_privkey_t* key,
                            const botan_mp_t scalar,
                            const char* curve_name);

BOTAN_PUBLIC_API(2,2)
int botan_pubkey_load_sm2(botan_pubkey_t* key,
                          const botan_mp_t public_x,
                          const botan_mp_t public_y,
                          const char* curve_name);

BOTAN_PUBLIC_API(2,2)
int botan_privkey_load_sm2(botan_privkey_t* key,
                           const botan_mp_t scalar,
                           const char* curve_name);

BOTAN_PUBLIC_API(2,2) BOTAN_DEPRECATED("Use botan_pubkey_load_sm2")
int botan_pubkey_load_sm2_enc(botan_pubkey_t* key,
                              const botan_mp_t public_x,
                              const botan_mp_t public_y,
                              const char* curve_name);

BOTAN_PUBLIC_API(2,2) BOTAN_DEPRECATED("Use botan_privkey_load_sm2")
int botan_privkey_load_sm2_enc(botan_privkey_t* key,
                               const botan_mp_t scalar,
                               const char* curve_name);

BOTAN_PUBLIC_API(2,3)
int botan_pubkey_sm2_compute_za(uint8_t out[],
                                size_t* out_len,
                                const char* ident,
                                const char* hash_algo,
                                const botan_pubkey_t key);

/*
* Public Key Encryption
*/
typedef struct botan_pk_op_encrypt_struct* botan_pk_op_encrypt_t;

BOTAN_PUBLIC_API(2,0) int botan_pk_op_encrypt_create(botan_pk_op_encrypt_t* op,
                                         botan_pubkey_t key,
                                         const char* padding,
                                         uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pk_op_encrypt_destroy(botan_pk_op_encrypt_t op);

BOTAN_PUBLIC_API(2,8) int botan_pk_op_encrypt_output_length(botan_pk_op_encrypt_t op,
                                                            size_t ptext_len,
                                                            size_t* ctext_len);

BOTAN_PUBLIC_API(2,0) int botan_pk_op_encrypt(botan_pk_op_encrypt_t op,
                                              botan_rng_t rng,
                                              uint8_t out[],
                                              size_t* out_len,
                                              const uint8_t plaintext[],
                                              size_t plaintext_len);

/*
* Public Key Decryption
*/
typedef struct botan_pk_op_decrypt_struct* botan_pk_op_decrypt_t;

BOTAN_PUBLIC_API(2,0) int botan_pk_op_decrypt_create(botan_pk_op_decrypt_t* op,
                                         botan_privkey_t key,
                                         const char* padding,
                                         uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pk_op_decrypt_destroy(botan_pk_op_decrypt_t op);

BOTAN_PUBLIC_API(2,8) int botan_pk_op_decrypt_output_length(botan_pk_op_decrypt_t op,
                                                            size_t ctext_len,
                                                            size_t* ptext_len);

BOTAN_PUBLIC_API(2,0) int botan_pk_op_decrypt(botan_pk_op_decrypt_t op,
                                  uint8_t out[], size_t* out_len,
                                  const uint8_t ciphertext[], size_t ciphertext_len);

/*
* Signature Generation
*/
typedef struct botan_pk_op_sign_struct* botan_pk_op_sign_t;

BOTAN_PUBLIC_API(2,0)
int botan_pk_op_sign_create(botan_pk_op_sign_t* op,
                            botan_privkey_t key,
                            const char* hash_and_padding,
                            uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pk_op_sign_destroy(botan_pk_op_sign_t op);

BOTAN_PUBLIC_API(2,8) int botan_pk_op_sign_output_length(botan_pk_op_sign_t op, size_t* olen);

BOTAN_PUBLIC_API(2,0) int botan_pk_op_sign_update(botan_pk_op_sign_t op, const uint8_t in[], size_t in_len);

BOTAN_PUBLIC_API(2,0)
int botan_pk_op_sign_finish(botan_pk_op_sign_t op, botan_rng_t rng,
                            uint8_t sig[], size_t* sig_len);

/*
* Signature Verification
*/
typedef struct botan_pk_op_verify_struct* botan_pk_op_verify_t;

BOTAN_PUBLIC_API(2,0)
int botan_pk_op_verify_create(botan_pk_op_verify_t* op,
                              botan_pubkey_t key,
                              const char* hash_and_padding,
                              uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pk_op_verify_destroy(botan_pk_op_verify_t op);

BOTAN_PUBLIC_API(2,0) int botan_pk_op_verify_update(botan_pk_op_verify_t op, const uint8_t in[], size_t in_len);
BOTAN_PUBLIC_API(2,0) int botan_pk_op_verify_finish(botan_pk_op_verify_t op, const uint8_t sig[], size_t sig_len);

/*
* Key Agreement
*/
typedef struct botan_pk_op_ka_struct* botan_pk_op_ka_t;

BOTAN_PUBLIC_API(2,0)
int botan_pk_op_key_agreement_create(botan_pk_op_ka_t* op,
                                     botan_privkey_t key,
                                     const char* kdf,
                                     uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_pk_op_key_agreement_destroy(botan_pk_op_ka_t op);

BOTAN_PUBLIC_API(2,0) int botan_pk_op_key_agreement_export_public(botan_privkey_t key,
                                                      uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,8) int botan_pk_op_key_agreement_size(botan_pk_op_ka_t op, size_t* out_len);

BOTAN_PUBLIC_API(2,0)
int botan_pk_op_key_agreement(botan_pk_op_ka_t op,
                              uint8_t out[], size_t* out_len,
                              const uint8_t other_key[], size_t other_key_len,
                              const uint8_t salt[], size_t salt_len);

BOTAN_PUBLIC_API(2,0) int botan_pkcs_hash_id(const char* hash_name, uint8_t pkcs_id[], size_t* pkcs_id_len);


/*
*
* @param mce_key must be a McEliece key
* ct_len should be pt_len + n/8 + a few?
*/
BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Poorly specified, avoid in new code")
int botan_mceies_encrypt(botan_pubkey_t mce_key,
                         botan_rng_t rng,
                         const char* aead,
                         const uint8_t pt[], size_t pt_len,
                         const uint8_t ad[], size_t ad_len,
                         uint8_t ct[], size_t* ct_len);

BOTAN_PUBLIC_API(2,0) BOTAN_DEPRECATED("Poorly specified, avoid in new code")
int botan_mceies_decrypt(botan_privkey_t mce_key,
                         const char* aead,
                         const uint8_t ct[], size_t ct_len,
                         const uint8_t ad[], size_t ad_len,
                         uint8_t pt[], size_t* pt_len);

/*
* X.509 certificates
**************************/

typedef struct botan_x509_cert_struct* botan_x509_cert_t;

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_load(botan_x509_cert_t* cert_obj, const uint8_t cert[], size_t cert_len);
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_load_file(botan_x509_cert_t* cert_obj, const char* filename);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_destroy(botan_x509_cert_t cert);

BOTAN_PUBLIC_API(2,8) int botan_x509_cert_dup(botan_x509_cert_t* new_cert, botan_x509_cert_t cert);

/* Prefer botan_x509_cert_not_before and botan_x509_cert_not_after */
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_time_starts(botan_x509_cert_t cert, char out[], size_t* out_len);
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_time_expires(botan_x509_cert_t cert, char out[], size_t* out_len);

BOTAN_PUBLIC_API(2,8) int botan_x509_cert_not_before(botan_x509_cert_t cert, uint64_t* time_since_epoch);
BOTAN_PUBLIC_API(2,8) int botan_x509_cert_not_after(botan_x509_cert_t cert, uint64_t* time_since_epoch);

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_fingerprint(botan_x509_cert_t cert, const char* hash, uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_serial_number(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_authority_key_id(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);
BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_subject_key_id(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_public_key_bits(botan_x509_cert_t cert,
                                                  uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_get_public_key(botan_x509_cert_t cert, botan_pubkey_t* key);

BOTAN_PUBLIC_API(2,0)
int botan_x509_cert_get_issuer_dn(botan_x509_cert_t cert,
                                  const char* key, size_t index,
                                  uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,0)
int botan_x509_cert_get_subject_dn(botan_x509_cert_t cert,
                                   const char* key, size_t index,
                                   uint8_t out[], size_t* out_len);

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_to_string(botan_x509_cert_t cert, char out[], size_t* out_len);

/* Must match values of Key_Constraints in key_constraints.h */
enum botan_x509_cert_key_constraints {
   NO_CONSTRAINTS     = 0,
   DIGITAL_SIGNATURE  = 32768,
   NON_REPUDIATION    = 16384,
   KEY_ENCIPHERMENT   = 8192,
   DATA_ENCIPHERMENT  = 4096,
   KEY_AGREEMENT      = 2048,
   KEY_CERT_SIGN      = 1024,
   CRL_SIGN           = 512,
   ENCIPHER_ONLY      = 256,
   DECIPHER_ONLY      = 128
};

BOTAN_PUBLIC_API(2,0) int botan_x509_cert_allowed_usage(botan_x509_cert_t cert, unsigned int key_usage);

/**
* Check if the certificate matches the specified hostname via alternative name or CN match.
* RFC 5280 wildcards also supported.
*/
BOTAN_PUBLIC_API(2,5) int botan_x509_cert_hostname_match(botan_x509_cert_t cert, const char* hostname);

/**
* Returns 0 if the validation was successful, 1 if validation failed,
* and negative on error. A status code with details is written to
* *validation_result
*
* Intermediates or trusted lists can be null
* Trusted path can be null
*/
BOTAN_PUBLIC_API(2,8) int botan_x509_cert_verify(
   int* validation_result,
   botan_x509_cert_t cert,
   const botan_x509_cert_t* intermediates,
   size_t intermediates_len,
   const botan_x509_cert_t* trusted,
   size_t trusted_len,
   const char* trusted_path,
   size_t required_strength,
   const char* hostname,
   uint64_t reference_time);

/**
* Returns a pointer to a static character string explaining the status code,
* or else NULL if unknown.
*/
BOTAN_PUBLIC_API(2,8) const char* botan_x509_cert_validation_status(int code);

/**
 * Key wrapping as per RFC 3394
 */
BOTAN_PUBLIC_API(2,2)
int botan_key_wrap3394(const uint8_t key[], size_t key_len,
                       const uint8_t kek[], size_t kek_len,
                       uint8_t wrapped_key[], size_t *wrapped_key_len);

BOTAN_PUBLIC_API(2,2)
int botan_key_unwrap3394(const uint8_t wrapped_key[], size_t wrapped_key_len,
                         const uint8_t kek[], size_t kek_len,
                         uint8_t key[], size_t *key_len);

/**
* HOTP
*/

typedef struct botan_hotp_struct* botan_hotp_t;

/**
* Initialize a HOTP instance
*/
BOTAN_PUBLIC_API(2,8)
int botan_hotp_init(botan_hotp_t* hotp,
                    const uint8_t key[], size_t key_len,
                    const char* hash_algo,
                    size_t digits);

/**
* Destroy a HOTP instance
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,8)
int botan_hotp_destroy(botan_hotp_t hotp);

/**
* Generate a HOTP code for the provided counter
*/
BOTAN_PUBLIC_API(2,8)
int botan_hotp_generate(botan_hotp_t hotp,
                        uint32_t* hotp_code,
                        uint64_t hotp_counter);

/**
* Verify a HOTP code
*/
BOTAN_PUBLIC_API(2,8)
int botan_hotp_check(botan_hotp_t hotp,
                     uint64_t* next_hotp_counter,
                     uint32_t hotp_code,
                     uint64_t hotp_counter,
                     size_t resync_range);


/**
* TOTP
*/

typedef struct botan_totp_struct* botan_totp_t;

/**
* Initialize a TOTP instance
*/
BOTAN_PUBLIC_API(2,8)
int botan_totp_init(botan_totp_t* totp,
                    const uint8_t key[], size_t key_len,
                    const char* hash_algo,
                    size_t digits,
                    size_t time_step);

/**
* Destroy a TOTP instance
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,8)
int botan_totp_destroy(botan_totp_t totp);

/**
* Generate a TOTP code for the provided timestamp
* @param totp the TOTP object
* @param totp_code the OTP code will be written here
* @param timestamp the current local timestamp
*/
BOTAN_PUBLIC_API(2,8)
int botan_totp_generate(botan_totp_t totp,
                        uint32_t* totp_code,
                        uint64_t timestamp);

/**
* Verify a TOTP code
* @param totp the TOTP object
* @param totp_code the presented OTP
* @param timestamp the current local timestamp
* @param acceptable_clock_drift specifies the acceptable amount
* of clock drift (in terms of time steps) between the two hosts.
*/
BOTAN_PUBLIC_API(2,8)
int botan_totp_check(botan_totp_t totp,
                     uint32_t totp_code,
                     uint64_t timestamp,
                     size_t acceptable_clock_drift);


/**
* Format Preserving Encryption
*/

typedef struct botan_fpe_struct* botan_fpe_t;

#define BOTAN_FPE_FLAG_FE1_COMPAT_MODE 1

BOTAN_PUBLIC_API(2,8)
int botan_fpe_fe1_init(botan_fpe_t* fpe, botan_mp_t n,
                       const uint8_t key[], size_t key_len,
                       size_t rounds, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_PUBLIC_API(2,8)
int botan_fpe_destroy(botan_fpe_t fpe);

BOTAN_PUBLIC_API(2,8)
int botan_fpe_encrypt(botan_fpe_t fpe, botan_mp_t x, const uint8_t tweak[], size_t tweak_len);

BOTAN_PUBLIC_API(2,8)
int botan_fpe_decrypt(botan_fpe_t fpe, botan_mp_t x, const uint8_t tweak[], size_t tweak_len);

#ifdef __cplusplus
}
#endif

#endif