rsa-sha256-verify.c

   1 /* rsa-sha256-verify.c
   2
   3    Verifying signatures created with RSA and SHA256.
   4
   5    Copyright (C) 2001, 2003, 2006 Niels Möller
   6
   7    This file is part of GNU Nettle.
   8
   9    GNU Nettle is free software: you can redistribute it and/or
  10    modify it under the terms of either:
  11
  12      * the GNU Lesser General Public License as published by the Free
  13        Software Foundation; either version 3 of the License, or (at your
  14        option) any later version.
  15
  16    or
  17
  18      * the GNU General Public License as published by the Free
  19        Software Foundation; either version 2 of the License, or (at your
  20        option) any later version.
  21
  22    or both in parallel, as here.
  23
  24    GNU Nettle is distributed in the hope that it will be useful,
  25    but WITHOUT ANY WARRANTY; without even the implied warranty of
  26    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  27    General Public License for more details.
  28
  29    You should have received copies of the GNU General Public License and
  30    the GNU Lesser General Public License along with this program.  If
  31    not, see http://www.gnu.org/licenses/.
  32 */
  33
  34 #if HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37
  38 #include <assert.h>
  39
  40 #include "rsa.h"
  41 #include "rsa-internal.h"
  42
  43 #include "bignum.h"
  44 #include "pkcs1.h"
  45
  46 int
  47 rsa_sha256_verify(const struct rsa_public_key *key,
  48                   struct sha256_ctx *hash,
  49                   const mpz_t s)
  50 {
  51   int res;
  52   mpz_t m;
  53
  54   mpz_init(m);
  55
  56   res = (pkcs1_rsa_sha256_encode(m, key->size, hash)
  57          &&_rsa_verify(key, m, s));
  58
  59   mpz_clear(m);
  60
  61   return res;
  62 }
  63
  64 int
  65 rsa_sha256_verify_digest(const struct rsa_public_key *key,
  66                          const uint8_t *digest,
  67                          const mpz_t s)
  68 {
  69   int res;
  70   mpz_t m;
  71
  72   mpz_init(m);
  73
  74   res = (pkcs1_rsa_sha256_encode_digest(m, key->size, digest)
  75          && _rsa_verify(key, m, s));
  76
  77   mpz_clear(m);
  78
  79   return res;
  80 }