67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
/* 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_done(omac_state *state, unsigned char *out, unsigned long *outlen)
|
|
{
|
|
int err, mode, x;
|
|
|
|
_ARGCHK(state != NULL);
|
|
_ARGCHK(out != 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;
|
|
}
|
|
|
|
/* figure out mode */
|
|
if (state->buflen != state->blklen) {
|
|
/* add the 0x80 byte */
|
|
state->block[state->buflen++] = 0x80;
|
|
|
|
/* pad with 0x00 */
|
|
while (state->buflen < state->blklen) {
|
|
state->block[state->buflen++] = 0x00;
|
|
}
|
|
mode = 1;
|
|
} else {
|
|
mode = 0;
|
|
}
|
|
|
|
/* now xor prev + Lu[mode] */
|
|
for (x = 0; x < state->blklen; x++) {
|
|
state->block[x] ^= state->prev[x] ^ state->Lu[mode][x];
|
|
}
|
|
|
|
/* encrypt it */
|
|
cipher_descriptor[state->cipher_idx].ecb_encrypt(state->block, state->block, &state->key);
|
|
|
|
/* output it */
|
|
for (x = 0; x < state->blklen && (unsigned long)x < *outlen; x++) {
|
|
out[x] = state->block[x];
|
|
}
|
|
*outlen = x;
|
|
|
|
#ifdef CLEAN_STACK
|
|
zeromem(state, sizeof(*state));
|
|
#endif
|
|
return CRYPT_OK;
|
|
}
|
|
|
|
#endif
|
|
|