1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file cbc_start.c
14 CBC implementation, start chain, Tom St Denis
15 */
16
17 #ifdef LTC_CBC_MODE
18
19 /**
20 Initialize a CBC context
21 @param cipher The index of the cipher desired
22 @param IV The initialization vector
23 @param key The secret key
24 @param keylen The length of the secret key (octets)
25 @param num_rounds Number of rounds in the cipher desired (0 for default)
26 @param cbc The CBC state to initialize
27 @return CRYPT_OK if successful
28 */
cbc_start(int cipher,const unsigned char * IV,const unsigned char * key,int keylen,int num_rounds,symmetric_CBC * cbc)29 int cbc_start(int cipher, const unsigned char *IV, const unsigned char *key,
30 int keylen, int num_rounds, symmetric_CBC *cbc)
31 {
32 int x, err;
33
34 LTC_ARGCHK(IV != NULL);
35 LTC_ARGCHK(key != NULL);
36 LTC_ARGCHK(cbc != NULL);
37
38 /* bad param? */
39 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
40 return err;
41 }
42
43 /* setup cipher */
44 if ((err = cipher_descriptor[cipher]->setup(key, keylen, num_rounds, &cbc->key)) != CRYPT_OK) {
45 return err;
46 }
47
48 /* copy IV */
49 cbc->blocklen = cipher_descriptor[cipher]->block_length;
50 cbc->cipher = cipher;
51 for (x = 0; x < cbc->blocklen; x++) {
52 cbc->IV[x] = IV[x];
53 }
54 return CRYPT_OK;
55 }
56
57 #endif
58
59 /* ref: $Format:%D$ */
60 /* git commit: $Format:%H$ */
61 /* commit time: $Format:%ai$ */
62