New example program.

Rev: src/nettle/examples/rsa-verify.c:1.1

examples/rsa-verify.c

+/* rsa-verify.c
+ *
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 Niels Mller
+ *  
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ * 
+ * The nettle library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#if !WITH_PUBLIC_KEY
+int
+main(int argc, char **argv)
+{
+  fprintf(stderr,
+	  "You need to install GMP somewhere where Nettle can find it,\n"
+	  "and recompile Nettle\n");
+  return EXIT_FAILURE;
+}
+#else /* WITH_PUBLIC_KEY */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "rsa.h"
+#include "io.h"
+
+static int
+read_signature(const char *name, mpz_t s)
+{
+  char *buffer;
+  unsigned length;
+  int res;
+  
+  length = read_file(name, 0, &buffer);
+  if (!length)
+    return 0;
+
+  res = (mpz_set_str(s, buffer, 16) == 0);
+  free(buffer);
+
+  return res;
+}
+
+int
+main(int argc, char **argv)
+{
+  struct rsa_public_key key;
+  struct sha1_ctx hash;
+  mpz_t s;
+  
+  if (argc != 3)
+    {
+      fprintf(stderr, "Usage: rsa-sign PUBLIC-KEY SIGNATURE-FILE < file\n");
+      return EXIT_FAILURE;
+    }
+
+  rsa_init_public_key(&key);
+  
+  if (!read_rsa_key(argv[1], &key, NULL))
+    {
+      fprintf(stderr, "Invalid key\n");
+      return EXIT_FAILURE;
+    }
+
+  mpz_init(s);
+
+  if (!read_signature(argv[2], s))
+    {
+      fprintf(stderr, "Failed to read signature file `%s'\n",
+	      argv[2]);
+      return EXIT_FAILURE;
+    }
+  
+  sha1_init(&hash);
+  if (!hash_file(&nettle_sha1, &hash, stdin))
+    {
+      fprintf(stderr, "Failed reading stdin: %s\n",
+	      strerror(errno));
+      return 0;
+    }
+
+  if (!rsa_sha1_verify(&key, &hash, s))
+    {
+      fprintf(stderr, "Invalid signature!\n");
+      return EXIT_FAILURE;
+    }
+    
+  mpz_clear(s);
+  rsa_clear_public_key(&key);
+
+  return EXIT_SUCCESS;
+}
+#endif /* WITH_PUBLIC_KEY */