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 (at) 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 */ 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
