isprime.c

来自「支持SSL v2/v3, TLS, PKCS #5, PKCS #7, PKCS」· C语言 代码 · 共 119 行

/*
 *  isprime.c
 *
 *  Probabilistic primality tester command-line tool
 *
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is the MPI Arbitrary Precision Integer Arithmetic
 * library.
 *
 * The Initial Developer of the Original Code is Michael J. Fromberger.
 * Portions created by Michael J. Fromberger are 
 * Copyright (C) 1998, 1999, 2000 Michael J. Fromberger. 
 * All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable
 * instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the GPL.
 *
 *  $Id: isprime.c,v 1.1 2000/07/14 00:44:58 nelsonb%netscape.com Exp $
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mpi.h"
#include "mpprime.h"

#define  RM_TESTS       15   /* how many iterations of Rabin-Miller? */
#define  MINIMUM        1024 /* don't bother us with a < this        */

int      g_tests = RM_TESTS;
char    *g_prog = NULL;

int main(int argc, char *argv[])
{
  mp_int   a;
  mp_digit np = prime_tab_size; /* from mpprime.h */
  int      res = 0;

  g_prog = argv[0];

  if(argc < 2) {
    fprintf(stderr, "Usage: %s <a>, where <a> is a decimal integer\n"
	    "Use '0x' prefix for a hexadecimal value\n", g_prog);
    return 1;
  }

  /* Read number of tests from environment, if present */
  {
    char *tmp;

    if((tmp = getenv("RM_TESTS")) != NULL) {
      if((g_tests = atoi(tmp)) <= 0)
	g_tests = RM_TESTS;
    }
  }

  mp_init(&a);
  if(argv[1][0] == '0' && argv[1][1] == 'x')
    mp_read_radix(&a, argv[1] + 2, 16);
  else
    mp_read_radix(&a, argv[1], 10);

  if(mp_cmp_d(&a, MINIMUM) <= 0) {
    fprintf(stderr, "%s: please use a value greater than %d\n", 
	    g_prog, MINIMUM);
    mp_clear(&a);
    return 1;
  }

  /* Test for divisibility by small primes */
  if(mpp_divis_primes(&a, &np) != MP_NO) {
    printf("Not prime (divisible by small prime %d)\n", np);
    res = 2;
    goto CLEANUP;
  }

  /* Test with Fermat's test, using 2 as a witness */
  if(mpp_fermat(&a, 2) != MP_YES) {
    printf("Not prime (failed Fermat test)\n");
    res = 2;
    goto CLEANUP;
  }
 
  /* Test with Rabin-Miller probabilistic test */
  if(mpp_pprime(&a, g_tests) == MP_NO) {
      printf("Not prime (failed pseudoprime test)\n");
      res = 2;
      goto CLEANUP;
  }

  printf("Probably prime, 1 in 4^%d chance of false positive\n", g_tests);

CLEANUP:
  mp_clear(&a);
  
  return res;

}