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

   1 /* rsa-sign.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 /* string.h must be included before gmp.h */
  35 #include "rsa.h"
  36 #include "io.h"
  37
  38 int
  39 main(int argc, char **argv)
  40 {
  41   struct rsa_private_key key;
  42   struct sha1_ctx hash;
  43   mpz_t s;
  44
  45   if (argc != 2)
  46     {
  47       werror("Usage: rsa-sign PRIVATE-KEY < file\n");
  48       return EXIT_FAILURE;
  49     }
  50
  51   rsa_private_key_init(&key);
  52
  53   if (!read_rsa_key(argv[1], NULL, &key))
  54     {
  55       werror("Invalid key\n");
  56       return EXIT_FAILURE;
  57     }
  58
  59   sha1_init(&hash);
  60   if (!hash_file(&nettle_sha1, &hash, stdin))
  61     {
  62       werror("Failed reading stdin: %s\n",
  63               strerror(errno));
  64       return 0;
  65     }
  66
  67   mpz_init(s);
  68   if (!rsa_sha1_sign(&key, &hash, s))
  69     {
  70       werror("RSA key too small\n");
  71       return 0;
  72     }
  73
  74   if (!mpz_out_str(stdout, 16, s))
  75     {
  76       werror("Failed writing signature: %s\n",
  77               strerror(errno));
  78       return 0;
  79     }
  80
  81   putchar('\n');
  82
  83   mpz_clear(s);
  84   rsa_private_key_clear(&key);
  85
  86   return EXIT_SUCCESS;
  87 }