/* 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_done.c  XCBC Support, terminate the state*/#ifdef LTC_XCBC/** Terminate the XCBC-MAC state  @param xcbc     XCBC state to terminate  @param out      [out] Destination for the MAC tag  @param outlen   [in/out] Destination size and final tag size  Return CRYPT_OK on success*/int xcbc_done(xcbc_state *xcbc, unsigned char *out, unsigned long *outlen){   int err, x;   LTC_ARGCHK(xcbc != NULL);   LTC_ARGCHK(out  != NULL);   /* check structure */   if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) {      return err;   }   if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) ||       (xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) {      return CRYPT_INVALID_ARG;   }   /* which key do we use? */   if (xcbc->buflen == xcbc->blocksize) {      /* k2 */      for (x = 0; x < xcbc->blocksize; x++) {         xcbc->IV[x] ^= xcbc->K[1][x];      }   } else {      xcbc->IV[xcbc->buflen] ^= 0x80;      /* k3 */      for (x = 0; x < xcbc->blocksize; x++) {         xcbc->IV[x] ^= xcbc->K[2][x];      }   }   /* encrypt */   cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);   cipher_descriptor[xcbc->cipher].done(&xcbc->key);   /* extract tag */   for (x = 0; x < xcbc->blocksize && (unsigned long)x < *outlen; x++) {      out[x] = xcbc->IV[x];   }   *outlen = x;  #ifdef LTC_CLEAN_STACK   zeromem(xcbc, sizeof(*xcbc));#endif   return CRYPT_OK;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_done.c,v $ *//* $Revision: 1.4 $ *//* $Date: 2006/11/07 03:23:46 $ */