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
|
/*
* xfm.c
*
* Crypto transform implementation
*
* David A. McGrew
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2001-2006, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "cryptoalg.h"
#include "aes_cbc.h"
#include "hmac.h"
#include "crypto_kernel.h" /* for crypto_get_random() */
#define KEY_LEN 16
#define ENC_KEY_LEN 16
#define MAC_KEY_LEN 16
#define IV_LEN 16
#define TAG_LEN 12
#define MAX_EXPAND 27
err_status_t
aes_128_cbc_hmac_sha1_96_func(void *key,
void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len,
void *auth_tag) {
aes_cbc_ctx_t aes_ctx;
hmac_ctx_t hmac_ctx;
unsigned char enc_key[ENC_KEY_LEN];
unsigned char mac_key[MAC_KEY_LEN];
err_status_t status;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
/* derive encryption and authentication keys from the input key */
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "ENC", 3, ENC_KEY_LEN, enc_key);
if (status) return status;
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "MAC", 3, MAC_KEY_LEN, mac_key);
if (status) return status;
/* perform encryption and authentication */
/* set aes key */
status = aes_cbc_context_init(&aes_ctx, key, ENC_KEY_LEN, direction_encrypt);
if (status) return status;
/* set iv */
status = crypto_get_random(iv, IV_LEN);
if (status) return status;
status = aes_cbc_set_iv(&aes_ctx, iv);
/* encrypt the opaque data */
status = aes_cbc_nist_encrypt(&aes_ctx, opaque, opaque_len);
if (status) return status;
/* authenticate clear and opaque data */
status = hmac_init(&hmac_ctx, mac_key, MAC_KEY_LEN);
if (status) return status;
status = hmac_start(&hmac_ctx);
if (status) return status;
status = hmac_update(&hmac_ctx, clear, clear_len);
if (status) return status;
status = hmac_compute(&hmac_ctx, opaque, *opaque_len, TAG_LEN, auth_tag);
if (status) return status;
}
return err_status_ok;
}
err_status_t
aes_128_cbc_hmac_sha1_96_inv(void *key,
void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len,
void *auth_tag) {
aes_cbc_ctx_t aes_ctx;
hmac_ctx_t hmac_ctx;
unsigned char enc_key[ENC_KEY_LEN];
unsigned char mac_key[MAC_KEY_LEN];
unsigned char tmp_tag[TAG_LEN];
unsigned char *tag = auth_tag;
err_status_t status;
int i;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
/* derive encryption and authentication keys from the input key */
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "ENC", 3, ENC_KEY_LEN, enc_key);
if (status) return status;
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "MAC", 3, MAC_KEY_LEN, mac_key);
if (status) return status;
/* perform encryption and authentication */
/* set aes key */
status = aes_cbc_context_init(&aes_ctx, key, ENC_KEY_LEN, direction_decrypt);
if (status) return status;
/* set iv */
status = rand_source_get_octet_string(iv, IV_LEN);
if (status) return status;
status = aes_cbc_set_iv(&aes_ctx, iv);
/* encrypt the opaque data */
status = aes_cbc_nist_decrypt(&aes_ctx, opaque, opaque_len);
if (status) return status;
/* authenticate clear and opaque data */
status = hmac_init(&hmac_ctx, mac_key, MAC_KEY_LEN);
if (status) return status;
status = hmac_start(&hmac_ctx);
if (status) return status;
status = hmac_update(&hmac_ctx, clear, clear_len);
if (status) return status;
status = hmac_compute(&hmac_ctx, opaque, *opaque_len, TAG_LEN, tmp_tag);
if (status) return status;
/* compare the computed tag with the one provided as input */
for (i=0; i < TAG_LEN; i++)
if (tmp_tag[i] != tag[i])
return err_status_auth_fail;
}
return err_status_ok;
}
#define ENC 1
#define DEBUG 0
err_status_t
aes_128_cbc_hmac_sha1_96_enc(void *key,
const void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len) {
aes_cbc_ctx_t aes_ctx;
hmac_ctx_t hmac_ctx;
unsigned char enc_key[ENC_KEY_LEN];
unsigned char mac_key[MAC_KEY_LEN];
unsigned char *auth_tag;
err_status_t status;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
#if DEBUG
printf("ENC using key %s\n", octet_string_hex_string(key, KEY_LEN));
#endif
/* derive encryption and authentication keys from the input key */
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "ENC", 3, ENC_KEY_LEN, enc_key);
if (status) return status;
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "MAC", 3, MAC_KEY_LEN, mac_key);
if (status) return status;
/* perform encryption and authentication */
/* set aes key */
status = aes_cbc_context_init(&aes_ctx, key, ENC_KEY_LEN, direction_encrypt);
if (status) return status;
/* set iv */
status = rand_source_get_octet_string(iv, IV_LEN);
if (status) return status;
status = aes_cbc_set_iv(&aes_ctx, iv);
if (status) return status;
#if DEBUG
printf("plaintext len: %d\n", *opaque_len);
printf("iv: %s\n", octet_string_hex_string(iv, IV_LEN));
printf("plaintext: %s\n", octet_string_hex_string(opaque, *opaque_len));
#endif
#if ENC
/* encrypt the opaque data */
status = aes_cbc_nist_encrypt(&aes_ctx, opaque, opaque_len);
if (status) return status;
#endif
#if DEBUG
printf("ciphertext len: %d\n", *opaque_len);
printf("ciphertext: %s\n", octet_string_hex_string(opaque, *opaque_len));
#endif
/*
* authenticate clear and opaque data, then write the
* authentication tag to the location immediately following the
* ciphertext
*/
status = hmac_init(&hmac_ctx, mac_key, MAC_KEY_LEN);
if (status) return status;
status = hmac_start(&hmac_ctx);
if (status) return status;
status = hmac_update(&hmac_ctx, clear, clear_len);
if (status) return status;
#if DEBUG
printf("hmac input: %s\n",
octet_string_hex_string(clear, clear_len));
#endif
auth_tag = (unsigned char *)opaque;
auth_tag += *opaque_len;
status = hmac_compute(&hmac_ctx, opaque, *opaque_len, TAG_LEN, auth_tag);
if (status) return status;
#if DEBUG
printf("hmac input: %s\n",
octet_string_hex_string(opaque, *opaque_len));
#endif
/* bump up the opaque_len to reflect the authentication tag */
*opaque_len += TAG_LEN;
#if DEBUG
printf("prot data len: %d\n", *opaque_len);
printf("prot data: %s\n", octet_string_hex_string(opaque, *opaque_len));
#endif
}
return err_status_ok;
}
err_status_t
aes_128_cbc_hmac_sha1_96_dec(void *key,
const void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len) {
aes_cbc_ctx_t aes_ctx;
hmac_ctx_t hmac_ctx;
unsigned char enc_key[ENC_KEY_LEN];
unsigned char mac_key[MAC_KEY_LEN];
unsigned char tmp_tag[TAG_LEN];
unsigned char *auth_tag;
unsigned ciphertext_len;
err_status_t status;
int i;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
#if DEBUG
printf("DEC using key %s\n", octet_string_hex_string(key, KEY_LEN));
#endif
/* derive encryption and authentication keys from the input key */
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "ENC", 3, ENC_KEY_LEN, enc_key);
if (status) return status;
status = hmac_init(&hmac_ctx, key, KEY_LEN);
if (status) return status;
status = hmac_compute(&hmac_ctx, "MAC", 3, MAC_KEY_LEN, mac_key);
if (status) return status;
#if DEBUG
printf("prot data len: %d\n", *opaque_len);
printf("prot data: %s\n", octet_string_hex_string(opaque, *opaque_len));
#endif
/*
* set the protected data length to that of the ciphertext, by
* subtracting out the length of the authentication tag
*/
ciphertext_len = *opaque_len - TAG_LEN;
#if DEBUG
printf("ciphertext len: %d\n", ciphertext_len);
#endif
/* verify the authentication tag */
/*
* compute the authentication tag for the clear and opaque data,
* and write it to a temporary location
*/
status = hmac_init(&hmac_ctx, mac_key, MAC_KEY_LEN);
if (status) return status;
status = hmac_start(&hmac_ctx);
if (status) return status;
status = hmac_update(&hmac_ctx, clear, clear_len);
if (status) return status;
#if DEBUG
printf("hmac input: %s\n",
octet_string_hex_string(clear, clear_len));
#endif
status = hmac_compute(&hmac_ctx, opaque, ciphertext_len, TAG_LEN, tmp_tag);
if (status) return status;
#if DEBUG
printf("hmac input: %s\n",
octet_string_hex_string(opaque, ciphertext_len));
#endif
/*
* compare the computed tag with the one provided as input (which
* immediately follows the ciphertext)
*/
auth_tag = (unsigned char *)opaque;
auth_tag += ciphertext_len;
#if DEBUG
printf("auth_tag: %s\n", octet_string_hex_string(auth_tag, TAG_LEN));
printf("tmp_tag: %s\n", octet_string_hex_string(tmp_tag, TAG_LEN));
#endif
for (i=0; i < TAG_LEN; i++) {
if (tmp_tag[i] != auth_tag[i])
return err_status_auth_fail;
}
/* bump down the opaque_len to reflect the authentication tag */
*opaque_len -= TAG_LEN;
/* decrypt the confidential data */
status = aes_cbc_context_init(&aes_ctx, key, ENC_KEY_LEN, direction_decrypt);
if (status) return status;
status = aes_cbc_set_iv(&aes_ctx, iv);
if (status) return status;
#if DEBUG
printf("ciphertext: %s\n", octet_string_hex_string(opaque, *opaque_len));
printf("iv: %s\n", octet_string_hex_string(iv, IV_LEN));
#endif
#if ENC
status = aes_cbc_nist_decrypt(&aes_ctx, opaque, &ciphertext_len);
if (status) return status;
#endif
#if DEBUG
printf("plaintext len: %d\n", ciphertext_len);
printf("plaintext: %s\n",
octet_string_hex_string(opaque, ciphertext_len));
#endif
/* indicate the length of the plaintext */
*opaque_len = ciphertext_len;
}
return err_status_ok;
}
cryptoalg_ctx_t cryptoalg_ctx = {
aes_128_cbc_hmac_sha1_96_enc,
aes_128_cbc_hmac_sha1_96_dec,
KEY_LEN,
IV_LEN,
TAG_LEN,
MAX_EXPAND,
};
cryptoalg_t cryptoalg = &cryptoalg_ctx;
#define NULL_TAG_LEN 12
err_status_t
null_enc(void *key,
const void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len) {
int i;
unsigned char *auth_tag;
unsigned char *init_vec = iv;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
#if DEBUG
printf("NULL ENC using key %s\n", octet_string_hex_string(key, KEY_LEN));
printf("NULL_TAG_LEN: %d\n", NULL_TAG_LEN);
printf("plaintext len: %d\n", *opaque_len);
#endif
for (i=0; i < IV_LEN; i++)
init_vec[i] = i + (i * 16);
#if DEBUG
printf("iv: %s\n",
octet_string_hex_string(iv, IV_LEN));
printf("plaintext: %s\n",
octet_string_hex_string(opaque, *opaque_len));
#endif
auth_tag = opaque;
auth_tag += *opaque_len;
for (i=0; i < NULL_TAG_LEN; i++)
auth_tag[i] = i + (i * 16);
*opaque_len += NULL_TAG_LEN;
#if DEBUG
printf("protected data len: %d\n", *opaque_len);
printf("protected data: %s\n",
octet_string_hex_string(opaque, *opaque_len));
#endif
}
return err_status_ok;
}
err_status_t
null_dec(void *key,
const void *clear,
unsigned clear_len,
void *iv,
void *opaque,
unsigned *opaque_len) {
unsigned char *auth_tag;
/* check if we're doing authentication only */
if ((iv == NULL) && (opaque == NULL) && (opaque_len == NULL)) {
/* perform authentication only */
} else if ((iv == NULL) || (opaque == NULL) || (opaque_len == NULL)) {
/*
* bad parameter - we expect either all three pointers to be NULL,
* or none of those pointers to be NULL
*/
return err_status_fail;
} else {
#if DEBUG
printf("NULL DEC using key %s\n", octet_string_hex_string(key, KEY_LEN));
printf("protected data len: %d\n", *opaque_len);
printf("protected data: %s\n",
octet_string_hex_string(opaque, *opaque_len));
#endif
auth_tag = opaque;
auth_tag += (*opaque_len - NULL_TAG_LEN);
#if DEBUG
printf("iv: %s\n", octet_string_hex_string(iv, IV_LEN));
#endif
*opaque_len -= NULL_TAG_LEN;
#if DEBUG
printf("plaintext len: %d\n", *opaque_len);
printf("plaintext: %s\n",
octet_string_hex_string(opaque, *opaque_len));
#endif
}
return err_status_ok;
}
cryptoalg_ctx_t null_cryptoalg_ctx = {
null_enc,
null_dec,
KEY_LEN,
IV_LEN,
NULL_TAG_LEN,
MAX_EXPAND,
};
cryptoalg_t null_cryptoalg = &null_cryptoalg_ctx;
int
cryptoalg_get_id(cryptoalg_t c) {
if (c == cryptoalg)
return 1;
return 0;
}
cryptoalg_t
cryptoalg_find_by_id(int id) {
switch(id) {
case 1:
return cryptoalg;
default:
break;
}
return 0;
}
|
