54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
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*/
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/* OMAC1 Support by Tom St Denis (for 64 and 128 bit block ciphers only) */
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#include "mycrypt.h"
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#ifdef OMAC
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int omac_process(omac_state *state, const unsigned char *buf, unsigned long len)
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{
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int err, n, x;
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_ARGCHK(state != NULL);
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_ARGCHK(buf != NULL);
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if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) {
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return err;
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}
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if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) ||
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(state->blklen > (int)sizeof(state->block)) || (state->buflen > state->blklen)) {
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return CRYPT_INVALID_ARG;
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}
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while (len != 0) {
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/* ok if the block is full we xor in prev, encrypt and replace prev */
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if (state->buflen == state->blklen) {
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for (x = 0; x < state->blklen; x++) {
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state->block[x] ^= state->prev[x];
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}
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cipher_descriptor[state->cipher_idx].ecb_encrypt(state->block, state->prev, &state->key);
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state->buflen = 0;
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}
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/* add bytes */
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n = MIN(len, (unsigned long)(state->blklen - state->buflen));
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XMEMCPY(state->block + state->buflen, buf, n);
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state->buflen += n;
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len -= n;
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buf += n;
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}
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return CRYPT_OK;
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}
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#endif
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