1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /* see bearssl_block.h */
28 void
br_aes_big_cbcdec_init(br_aes_big_cbcdec_keys * ctx,const void * key,size_t len)29 br_aes_big_cbcdec_init(br_aes_big_cbcdec_keys *ctx,
30 const void *key, size_t len)
31 {
32 ctx->vtable = &br_aes_big_cbcdec_vtable;
33 ctx->num_rounds = br_aes_big_keysched_inv(ctx->skey, key, len);
34 }
35
36 /* see bearssl_block.h */
37 void
br_aes_big_cbcdec_run(const br_aes_big_cbcdec_keys * ctx,void * iv,void * data,size_t len)38 br_aes_big_cbcdec_run(const br_aes_big_cbcdec_keys *ctx,
39 void *iv, void *data, size_t len)
40 {
41 unsigned char *buf, *ivbuf;
42
43 ivbuf = iv;
44 buf = data;
45 while (len > 0) {
46 unsigned char tmp[16];
47 int i;
48
49 memcpy(tmp, buf, 16);
50 br_aes_big_decrypt(ctx->num_rounds, ctx->skey, buf);
51 for (i = 0; i < 16; i ++) {
52 buf[i] ^= ivbuf[i];
53 }
54 memcpy(ivbuf, tmp, 16);
55 buf += 16;
56 len -= 16;
57 }
58 }
59
60 /* see bearssl_block.h */
61 const br_block_cbcdec_class br_aes_big_cbcdec_vtable = {
62 sizeof(br_aes_big_cbcdec_keys),
63 16,
64 4,
65 (void (*)(const br_block_cbcdec_class **, const void *, size_t))
66 &br_aes_big_cbcdec_init,
67 (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t))
68 &br_aes_big_cbcdec_run
69 };
70