/* 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 OMACint 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