New file.

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

examples/rsa-keygen.c

+/* rsa-keygen.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 */
+
+/* For asprintf */
+#define _GNU_SOURCE
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if !HAVE_LIBGMP
+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;
+}
+#endif /* !HAVE_LIBGMP */
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "buffer.h"
+#include "rsa.h"
+#include "sexp.h"
+#include "yarrow.h"
+
+#define KEYSIZE 500
+#define ESIZE 30
+
+#define RANDOM_DEVICE "/dev/urandom"
+
+static void
+progress(void *ctx, int c)
+{
+  (void) ctx;
+  fputc(c, stderr);
+}
+
+static int
+write_file(const char *name, struct nettle_buffer *buffer)
+{
+  const uint8_t *data = buffer->contents;
+  unsigned length = buffer->size;
+  int fd = open(name, O_WRONLY | O_CREAT | O_TRUNC, 0600);
+  
+  if (fd < 0)
+    return 0;
+
+  while (length)
+    {
+      int res = write(fd, data, length);
+      if (res < 0)
+	{
+	  if (errno == EINTR)
+	    continue;
+	  else
+	    return 0;
+	}
+      data += res;
+      length -= res;
+    }
+
+  return 1;
+}
+
+int
+main(int argc, char **argv)
+{
+  struct yarrow256_ctx yarrow;
+  struct rsa_public_key pub;
+  struct rsa_private_key priv;
+  char buf[16];
+  int fd;
+
+  int c;
+  char *pub_name = NULL;
+  char *priv_name = NULL;;
+  struct stat sbuf;
+  
+  struct nettle_buffer pub_buffer;
+  struct nettle_buffer priv_buffer;
+
+  while ( (c = getopt(argc, argv, "o:")) != -1)
+    switch (c)
+      {
+      case 'o':
+	priv_name = optarg;
+	break;
+      case '?':
+	if (isprint (optopt))
+	  fprintf(stderr, "Unknown option `-%c'.\n", optopt);
+	else
+	  fprintf(stderr, "Unknown option character `\\x%x'.\n",
+		  optopt);
+	return EXIT_FAILURE;
+      default:
+	abort();
+      }
+
+  if (!priv_name)
+    {
+      fprintf(stderr, "No filename provided.\n");
+      return EXIT_FAILURE;
+    }
+
+  if (stat(priv_name, &sbuf) == 0)
+    {
+      fprintf(stderr, "The output file `%s' already exists.\n", priv_name);
+      return EXIT_FAILURE;
+    }
+
+  asprintf(&pub_name, "%s.pub", priv_name);
+  if (!pub_name)
+    {
+      fprintf(stderr, "Memory exhausted.\n");
+      return EXIT_FAILURE;
+    }
+  
+  if (stat(pub_name, &sbuf) == 0)
+    {
+      fprintf(stderr, "The output file `%s' already exists.\n", pub_name);
+      return EXIT_FAILURE;
+    }
+    
+  /* Read some data to seed the generator */
+  if ( ( (fd = open(RANDOM_DEVICE, O_RDONLY)) < 0)
+       || (sizeof(buf) != read(fd, buf, sizeof(buf))))
+    {
+      fprintf(stderr, "Failed to open `%s': %s\n",
+	      RANDOM_DEVICE, strerror(errno));
+      return EXIT_FAILURE;
+    }
+  
+  /* NOTE: No sources */
+  yarrow256_init(&yarrow, 0, NULL);
+  yarrow256_seed(&yarrow, sizeof(buf), buf);
+  
+  rsa_init_public_key(&pub);
+  rsa_init_private_key(&priv);
+
+  if (!rsa_generate_keypair
+      (&pub, &priv,
+       (void *) &yarrow, (nettle_random_func) yarrow256_random,
+       NULL, progress,
+       KEYSIZE, ESIZE))
+    {
+      fprintf(stderr, "Key generation failed.\n");
+      return EXIT_FAILURE;
+    }
+
+  nettle_buffer_init(&priv_buffer);
+  nettle_buffer_init(&pub_buffer);
+  
+  if (!rsa_keypair_to_sexp(&pub_buffer, &pub, NULL))
+    {
+      fprintf(stderr, "Formatting public key failed.\n");
+      return EXIT_FAILURE;
+    }
+
+  if (!rsa_keypair_to_sexp(&pub_buffer, &pub, &priv))
+    {
+      fprintf(stderr, "Formatting private key failed.\n");
+      return EXIT_FAILURE;
+    }
+  
+  if (!write_file(pub_name, &pub_buffer))
+    {
+      fprintf(stderr, "Failed to write public key: %s\n",
+	      strerror(errno));
+      return EXIT_FAILURE;
+    }
+
+  if (!write_file(priv_name, &priv_buffer))
+    {
+      fprintf(stderr, "Failed to write private key: %s\n",
+	      strerror(errno));
+      return EXIT_FAILURE;
+    }
+
+  return EXIT_SUCCESS;
+}