| /* 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 |
| */ |
| /* OMAC1 Support by Tom St Denis (for 64 and 128 bit block ciphers only) */ |
| #include "mycrypt.h" |
| |
| #ifdef OMAC |
| |
| int omac_process(omac_state *state, const unsigned char *buf, unsigned long len) |
| { |
| int err, n, x; |
| |
| _ARGCHK(state != NULL); |
| _ARGCHK(buf != NULL); |
| if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) { |
| return err; |
| } |
| |
| if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) || |
| (state->blklen > (int)sizeof(state->block)) || (state->buflen > state->blklen)) { |
| return CRYPT_INVALID_ARG; |
| } |
| |
| while (len != 0) { |
| /* ok if the block is full we xor in prev, encrypt and replace prev */ |
| if (state->buflen == state->blklen) { |
| for (x = 0; x < state->blklen; x++) { |
| state->block[x] ^= state->prev[x]; |
| } |
| cipher_descriptor[state->cipher_idx].ecb_encrypt(state->block, state->prev, &state->key); |
| state->buflen = 0; |
| } |
| |
| /* add bytes */ |
| n = MIN(len, (unsigned long)(state->blklen - state->buflen)); |
| memcpy(state->block + state->buflen, buf, n); |
| state->buflen += n; |
| len -= n; |
| buf += n; |
| } |
| |
| return CRYPT_OK; |
| } |
| |
| #endif |
| |