| /* 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@iahu.ca, http://libtomcrypt.org |
| */ |
| #include "mycrypt.h" |
| |
| #ifdef OFB |
| |
| int ofb_start(int cipher, const unsigned char *IV, const unsigned char *key, |
| int keylen, int num_rounds, symmetric_OFB *ofb) |
| { |
| int x, err; |
| |
| _ARGCHK(IV != NULL); |
| _ARGCHK(key != NULL); |
| _ARGCHK(ofb != NULL); |
| |
| if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { |
| return err; |
| } |
| |
| /* copy details */ |
| ofb->cipher = cipher; |
| ofb->blocklen = cipher_descriptor[cipher].block_length; |
| for (x = 0; x < ofb->blocklen; x++) { |
| ofb->IV[x] = IV[x]; |
| } |
| |
| /* init the cipher */ |
| ofb->padlen = ofb->blocklen; |
| return cipher_descriptor[cipher].setup(key, keylen, num_rounds, &ofb->key); |
| } |
| |
| #endif |