release/src/router/nettle/examples/rsa-verify.c

   1 /* rsa-verify.c
   2  *
   3  */
   4
   5 /* nettle, low-level cryptographics library
   6  *
   7  * Copyright (C) 2002 Niels Möller
   8  *
   9  * The nettle library is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or (at your
  12  * option) any later version.
  13  *
  14  * The nettle library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  16  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  17  * License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  22  * MA 02111-1301, USA.
  23  */
  24
  25 #if HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <errno.h>
  30 #include <stdlib.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33
  34 #include "rsa.h"
  35 #include "io.h"
  36
  37 static int
  38 read_signature(const char *name, mpz_t s)
  39 {
  40   char *buffer;
  41   unsigned length;
  42   int res;
  43
  44   length = read_file(name, 0, &buffer);
  45   if (!length)
  46     return 0;
  47
  48   res = (mpz_set_str(s, buffer, 16) == 0);
  49   free(buffer);
  50
  51   return res;
  52 }
  53
  54 int
  55 main(int argc, char **argv)
  56 {
  57   struct rsa_public_key key;
  58   struct sha1_ctx hash;
  59   mpz_t s;
  60
  61   if (argc != 3)
  62     {
  63       werror("Usage: rsa-verify PUBLIC-KEY SIGNATURE-FILE < FILE\n");
  64       return EXIT_FAILURE;
  65     }
  66
  67   rsa_public_key_init(&key);
  68
  69   if (!read_rsa_key(argv[1], &key, NULL))
  70     {
  71       werror("Invalid key\n");
  72       return EXIT_FAILURE;
  73     }
  74
  75   mpz_init(s);
  76
  77   if (!read_signature(argv[2], s))
  78     {
  79       werror("Failed to read signature file `%s'\n",
  80               argv[2]);
  81       return EXIT_FAILURE;
  82     }
  83
  84   sha1_init(&hash);
  85   if (!hash_file(&nettle_sha1, &hash, stdin))
  86     {
  87       werror("Failed reading stdin: %s\n",
  88               strerror(errno));
  89       return 0;
  90     }
  91
  92   if (!rsa_sha1_verify(&key, &hash, s))
  93     {
  94       werror("Invalid signature!\n");
  95       return EXIT_FAILURE;
  96     }
  97
  98   mpz_clear(s);
  99   rsa_public_key_clear(&key);
 100
 101   return EXIT_SUCCESS;
 102 }