usr/src/common/mpi/mpprime.c

   1 /*
   2  *  mpprime.c
   3  *
   4  *  Utilities for finding and working with prime and pseudo-prime
   5  *  integers
   6  *
   7  * ***** BEGIN LICENSE BLOCK *****
   8  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   9  *
  10  * The contents of this file are subject to the Mozilla Public License Version
  11  * 1.1 (the "License"); you may not use this file except in compliance with
  12  * the License. You may obtain a copy of the License at
  13  * http://www.mozilla.org/MPL/
  14  *
  15  * Software distributed under the License is distributed on an "AS IS" basis,
  16  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  17  * for the specific language governing rights and limitations under the
  18  * License.
  19  *
  20  * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
  21  *
  22  * The Initial Developer of the Original Code is
  23  * Michael J. Fromberger.
  24  * Portions created by the Initial Developer are Copyright (C) 1997
  25  * the Initial Developer. All Rights Reserved.
  26  *
  27  * Contributor(s):
  28  *   Netscape Communications Corporation
  29  *
  30  * Alternatively, the contents of this file may be used under the terms of
  31  * either the GNU General Public License Version 2 or later (the "GPL"), or
  32  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  33  * in which case the provisions of the GPL or the LGPL are applicable instead
  34  * of those above. If you wish to allow use of your version of this file only
  35  * under the terms of either the GPL or the LGPL, and not to allow others to
  36  * use your version of this file under the terms of the MPL, indicate your
  37  * decision by deleting the provisions above and replace them with the notice
  38  * and other provisions required by the GPL or the LGPL. If you do not delete
  39  * the provisions above, a recipient may use your version of this file under
  40  * the terms of any one of the MPL, the GPL or the LGPL.
  41  *
  42  * ***** END LICENSE BLOCK ***** */
  43 /*
  44  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  45  * Use is subject to license terms.
  46  *
  47  * Sun elects to use this software under the MPL license.
  48  */
  49
  50 #pragma ident   "%Z%%M% %I%     %E% SMI"
  51
  52 #include "mpi-priv.h"
  53 #include "mpprime.h"
  54 #include "mplogic.h"
  55 #ifndef _KERNEL
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #else
  59 #include <sys/random.h>
  60 #endif
  61
  62 #define SMALL_TABLE 0 /* determines size of hard-wired prime table */
  63
  64 #ifndef _KERNEL
  65 #define RANDOM() rand()
  66 #else
  67 #define RANDOM() foo_rand()
  68
  69 static int
  70 foo_rand()
  71 {
  72         int r;
  73         random_get_pseudo_bytes((uchar_t *)&r, sizeof (r));
  74         return (r);
  75 }
  76 #endif
  77
  78 /*
  79   mpp_random(a)
  80
  81   Assigns a random value to a.  This value is generated using the
  82   standard C library's rand() function, so it should not be used for
  83   cryptographic purposes, but it should be fine for primality testing,
  84   since all we really care about there is good statistical properties.
  85
  86   As many digits as a currently has are filled with random digits.
  87  */
  88
  89 mp_err  mpp_random(mp_int *a)
  90
  91 {
  92   mp_digit  next = 0;
  93   unsigned int       ix, jx;
  94
  95   ARGCHK(a != NULL, MP_BADARG);
  96
  97   for(ix = 0; ix < USED(a); ix++) {
  98     for(jx = 0; jx < sizeof(mp_digit); jx++) {
  99       next = (next << CHAR_BIT) | (RANDOM() & UCHAR_MAX);
 100     }
 101     DIGIT(a, ix) = next;
 102   }
 103
 104   return MP_OKAY;
 105
 106 } /* end mpp_random() */
 107
 108 /* }}} */
 109
 110 /* {{{ mpp_random_size(a, prec) */
 111
 112 mp_err  mpp_random_size(mp_int *a, mp_size prec)
 113 {
 114   mp_err   res;
 115
 116   ARGCHK(a != NULL && prec > 0, MP_BADARG);
 117
 118   if((res = s_mp_pad(a, prec)) != MP_OKAY)
 119     return res;
 120
 121   return mpp_random(a);
 122
 123 } /* end mpp_random_size() */