view pkcs_1_i2osp.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"

/* Integer to Octet I2OSP -- Tom St Denis */

#ifdef PKCS_1

/* always stores the same # of bytes, pads with leading zero bytes
   as required
 */
int pkcs_1_i2osp(mp_int *n, unsigned long modulus_len, unsigned char *out)
{
   int err;
   unsigned long size;

   size = mp_unsigned_bin_size(n);

   if (size > modulus_len) {
      return CRYPT_BUFFER_OVERFLOW;
   }

   /* store it */
   zeromem(out, modulus_len);
   if ((err = mp_to_unsigned_bin(n, out+(modulus_len-size))) != MP_OKAY) {
      return mpi_to_ltc_error(err);
   }
   return CRYPT_OK;
}

#endif /* PKCS_1 */