1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file cbc_start.c
15 CBC implementation, start chain, Tom St Denis
16 */
17
18 #ifdef LTC_CBC_MODE
19
20 /**
21 Initialize a CBC context
22 @param cipher The index of the cipher desired
23 @param IV The initial vector
24 @param key The secret key
25 @param keylen The length of the secret key (octets)
26 @param num_rounds Number of rounds in the cipher desired (0 for default)
27 @param cbc The CBC state to initialize
28 @return CRYPT_OK if successful
29 */
cbc_start(int cipher,const unsigned char * IV,const unsigned char * key,int keylen,int num_rounds,symmetric_CBC * cbc)30 int cbc_start(int cipher, const unsigned char *IV, const unsigned char *key,
31 int keylen, int num_rounds, symmetric_CBC *cbc)
32 {
33 int x, err;
34
35 LTC_ARGCHK(IV != NULL);
36 LTC_ARGCHK(key != NULL);
37 LTC_ARGCHK(cbc != NULL);
38
39 /* bad param? */
40 if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
41 return err;
42 }
43
44 /* setup cipher */
45 if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &cbc->key)) != CRYPT_OK) {
46 return err;
47 }
48
49 /* copy IV */
50 cbc->blocklen = cipher_descriptor[cipher].block_length;
51 cbc->cipher = cipher;
52 for (x = 0; x < cbc->blocklen; x++) {
53 cbc->IV[x] = IV[x];
54 }
55 return CRYPT_OK;
56 }
57
58 #endif
59
60 /* $Source: /cvs/libtom/libtomcrypt/src/modes/cbc/cbc_start.c,v $ */
61 /* $Revision: 1.5 $ */
62 /* $Date: 2006/06/29 01:46:46 $ */
63