security/nss/lib/freebl/mpi/utils/isprime.c

   1 /*
   2  *  isprime.c
   3  *
   4  *  Probabilistic primality tester command-line tool
   5  *
   6  * ***** BEGIN LICENSE BLOCK *****
   7  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   8  *
   9  * The contents of this file are subject to the Mozilla Public License Version
  10  * 1.1 (the "License"); you may not use this file except in compliance with
  11  * the License. You may obtain a copy of the License at
  12  * http://www.mozilla.org/MPL/
  13  *
  14  * Software distributed under the License is distributed on an "AS IS" basis,
  15  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  16  * for the specific language governing rights and limitations under the
  17  * License.
  18  *
  19  * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
  20  *
  21  * The Initial Developer of the Original Code is
  22  * Michael J. Fromberger.
  23  * Portions created by the Initial Developer are Copyright (C) 1998
  24  * the Initial Developer. All Rights Reserved.
  25  *
  26  * Contributor(s):
  27  *
  28  * Alternatively, the contents of this file may be used under the terms of
  29  * either the GNU General Public License Version 2 or later (the "GPL"), or
  30  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  31  * in which case the provisions of the GPL or the LGPL are applicable instead
  32  * of those above. If you wish to allow use of your version of this file only
  33  * under the terms of either the GPL or the LGPL, and not to allow others to
  34  * use your version of this file under the terms of the MPL, indicate your
  35  * decision by deleting the provisions above and replace them with the notice
  36  * and other provisions required by the GPL or the LGPL. If you do not delete
  37  * the provisions above, a recipient may use your version of this file under
  38  * the terms of any one of the MPL, the GPL or the LGPL.
  39  *
  40  * ***** END LICENSE BLOCK ***** */
  41 /* $Id: isprime.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 #include "mpi.h"
  48 #include "mpprime.h"
  49
  50 #define  RM_TESTS       15   /* how many iterations of Rabin-Miller? */
  51 #define  MINIMUM        1024 /* don't bother us with a < this        */
  52
  53 int      g_tests = RM_TESTS;
  54 char    *g_prog = NULL;
  55
  56 int main(int argc, char *argv[])
  57 {
  58   mp_int   a;
  59   mp_digit np = prime_tab_size; /* from mpprime.h */
  60   int      res = 0;
  61
  62   g_prog = argv[0];
  63
  64   if(argc < 2) {
  65     fprintf(stderr, "Usage: %s <a>, where <a> is a decimal integer\n"
  66             "Use '0x' prefix for a hexadecimal value\n", g_prog);
  67     return 1;
  68   }
  69
  70   /* Read number of tests from environment, if present */
  71   {
  72     char *tmp;
  73
  74     if((tmp = getenv("RM_TESTS")) != NULL) {
  75       if((g_tests = atoi(tmp)) <= 0)
  76         g_tests = RM_TESTS;
  77     }
  78   }
  79
  80   mp_init(&a);
  81   if(argv[1][0] == '0' && argv[1][1] == 'x')
  82     mp_read_radix(&a, argv[1] + 2, 16);
  83   else
  84     mp_read_radix(&a, argv[1], 10);
  85
  86   if(mp_cmp_d(&a, MINIMUM) <= 0) {
  87     fprintf(stderr, "%s: please use a value greater than %d\n",
  88             g_prog, MINIMUM);
  89     mp_clear(&a);
  90     return 1;
  91   }
  92
  93   /* Test for divisibility by small primes */
  94   if(mpp_divis_primes(&a, &np) != MP_NO) {
  95     printf("Not prime (divisible by small prime %d)\n", np);
  96     res = 2;
  97     goto CLEANUP;
  98   }
  99
 100   /* Test with Fermat's test, using 2 as a witness */
 101   if(mpp_fermat(&a, 2) != MP_YES) {
 102     printf("Not prime (failed Fermat test)\n");
 103     res = 2;
 104     goto CLEANUP;
 105   }
 106
 107   /* Test with Rabin-Miller probabilistic test */
 108   if(mpp_pprime(&a, g_tests) == MP_NO) {
 109       printf("Not prime (failed pseudoprime test)\n");
 110       res = 2;
 111       goto CLEANUP;
 112   }
 113
 114   printf("Probably prime, 1 in 4^%d chance of false positive\n", g_tests);
 115
 116 CLEANUP:
 117   mp_clear(&a);
 118
 119   return res;
 120
 121 }