/* 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@gmail.com, http://libtomcrypt.com */#include "tomcrypt.h"/**  @file xcbc_init.c  XCBC Support, start an XCBC state*/#ifdef LTC_XCBC/** Initialize XCBC-MAC state  @param xcbc    [out] XCBC state to initialize  @param cipher  Index of cipher to use  @param key     [in]  Secret key  @param keylen  Length of secret key in octets  Return CRYPT_OK on success*/int xcbc_init(xcbc_state *xcbc, int cipher, const unsigned char *key, unsigned long keylen){   int            x, y, err;   symmetric_key *skey;   LTC_ARGCHK(xcbc != NULL);   LTC_ARGCHK(key  != NULL);   /* schedule the key */   if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {      return err;   }#ifdef LTC_FAST   if (cipher_descriptor[cipher].block_length % sizeof(LTC_FAST_TYPE)) {       return CRYPT_INVALID_ARG;   }#endif   /* schedule the user key */   skey = XCALLOC(1, sizeof(*skey));   if (skey == NULL) {      return CRYPT_MEM;   }   if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, skey)) != CRYPT_OK) {      goto done;   }      /* make the three keys */   for (y = 0; y < 3; y++) {     for (x = 0; x < cipher_descriptor[cipher].block_length; x++) {        xcbc->K[y][x] = y + 1;     }     cipher_descriptor[cipher].ecb_encrypt(xcbc->K[y], xcbc->K[y], skey);   }   /* setup K1 */   err = cipher_descriptor[cipher].setup(xcbc->K[0], cipher_descriptor[cipher].block_length, 0, &xcbc->key);    /* setup struct */   zeromem(xcbc->IV, cipher_descriptor[cipher].block_length);   xcbc->blocksize = cipher_descriptor[cipher].block_length;   xcbc->cipher    = cipher;   xcbc->buflen    = 0;done:   cipher_descriptor[cipher].done(skey);#ifdef LTC_CLEAN_STACK   zeromem(skey, sizeof(*skey));#endif   XFREE(skey);   return err;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_init.c,v $ *//* $Revision: 1.4 $ *//* $Date: 2006/11/07 03:23:46 $ */