release/src/router/nettle/rsa-pkcs1-sign-tr.c

   1 /* rsa-pkcs1-sign-tr.c
   2  *
   3  * Creating timing resistant RSA signatures.
   4  */
   5
   6 /* nettle, low-level cryptographics library
   7  *
   8  * Copyright (C) 2012 Nikos Mavrogiannopoulos
   9  *
  10  * The nettle library is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or (at your
  13  * option) any later version.
  14  *
  15  * The nettle library is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  18  * License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  22  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  23  * MA 02111-1301, USA.
  24  */
  25
  26 #if HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include "rsa.h"
  31
  32 #include "pkcs1.h"
  33
  34 int
  35 rsa_pkcs1_sign_tr(const struct rsa_public_key *pub,
  36                   const struct rsa_private_key *key,
  37                   void *random_ctx, nettle_random_func *random,
  38                   unsigned length, const uint8_t *digest_info,
  39                   mpz_t s)
  40 {
  41   mpz_t ri;
  42
  43   if (pkcs1_rsa_digest_encode (s, key->size, length, digest_info))
  44     {
  45       mpz_init (ri);
  46
  47       _rsa_blind (pub, random_ctx, random, s, ri);
  48       rsa_compute_root(key, s, s);
  49       _rsa_unblind (pub, s, ri);
  50
  51       mpz_clear (ri);
  52
  53       return 1;
  54     }
  55   else
  56     {
  57       mpz_set_ui(s, 0);
  58       return 0;
  59     }
  60 }