view ctr_start.c @ 16:09ab3354aa21 libtomcrypt

propagate of e8bea23df30f9f46c647d06db3b223427b4e3604 and b0b6b4a8843b94d9f049cb5ffe0b1ae91ec1bf8b from branch 'au.asn.ucc.matt.ltc-orig' to 'au.asn.ucc.matt.ltc-db'
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:27:14 +0000
parents d7da3b1e1540
children
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/* 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, [email protected], http://libtomcrypt.org
 */
#include "mycrypt.h"

#ifdef CTR

int ctr_start(int cipher, const unsigned char *count, const unsigned char *key, int keylen, 
              int num_rounds, symmetric_CTR *ctr)
{
   int x, err;

   _ARGCHK(count != NULL);
   _ARGCHK(key != NULL);
   _ARGCHK(ctr != NULL);

   /* bad param? */
   if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
      return err;
   }

   /* setup cipher */
   if ((err = cipher_descriptor[cipher].setup(key, keylen, num_rounds, &ctr->key)) != CRYPT_OK) {
      return err;
   }

   /* copy ctr */
   ctr->blocklen = cipher_descriptor[cipher].block_length;
   ctr->cipher   = cipher;
   ctr->padlen   = 0;
   ctr->mode     = 0;
   for (x = 0; x < ctr->blocklen; x++) {
       ctr->ctr[x] = count[x];
   }
   cipher_descriptor[ctr->cipher].ecb_encrypt(ctr->ctr, ctr->pad, &ctr->key);
   return CRYPT_OK;
}

#endif