| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.org |
| */ |
| #include "tomcrypt.h" |
| |
| /** |
| @file cbc_start.c |
| CBC implementation, start chain, Tom St Denis |
| */ |
| |
| #ifdef CBC |
| |
| /** |
| Initialize a CBC context |
| @param cipher The index of the cipher desired |
| @param IV The initial vector |
| @param key The secret key |
| @param keylen The length of the secret key (octets) |
| @param num_rounds Number of rounds in the cipher desired (0 for default) |
| @param cbc The CBC state to initialize |
| @return CRYPT_OK if successful |
| */ |
| int cbc_start(int cipher, const unsigned char *IV, const unsigned char *key, |
| int keylen, int num_rounds, symmetric_CBC *cbc) |
| { |
| int x, err; |
| |
| LTC_ARGCHK(IV != NULL); |
| LTC_ARGCHK(key != NULL); |
| LTC_ARGCHK(cbc != NULL); |
| |
| /* bad param? */ |
| if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { |
| return err; |
| } |
| |
| /* setup cipher */ |
| if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &cbc->key)) != CRYPT_OK) { |
| return err; |
| } |
| |
| /* copy IV */ |
| cbc->blocklen = cipher_descriptor[cipher].block_length; |
| cbc->cipher = cipher; |
| for (x = 0; x < cbc->blocklen; x++) { |
| cbc->IV[x] = IV[x]; |
| } |
| return CRYPT_OK; |
| } |
| |
| #endif |