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97 lines
3.4 KiB
C
97 lines
3.4 KiB
C
/*
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* Blum, Blum & Shub PRNG using the MPI library
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
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*
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* The Initial Developer of the Original Code is
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* Michael J. Fromberger.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* $Id: bbs_rand.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */
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#include "bbs_rand.h"
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#define SEED 1
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#define MODULUS 2
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/* This modulus is the product of two randomly generated 512-bit
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prime integers, each of which is congruent to 3 (mod 4). */
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static char *bbs_modulus =
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"75A2A6E1D27393B86562B9CE7279A8403CB4258A637DAB5233465373E37837383EDC"
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"332282B8575927BC4172CE8C147B4894050EE9D2BDEED355C121037270CA2570D127"
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"7D2390CD1002263326635CC6B259148DE3A1A03201980A925E395E646A5E9164B0EC"
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"28559EBA58C87447245ADD0651EDA507056A1129E3A3E16E903D64B437";
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static int bbs_init = 0; /* flag set when library is initialized */
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static mp_int bbs_state; /* the current state of the generator */
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/* Suggested size of random seed data */
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int bbs_seed_size = (sizeof(bbs_modulus) / 2);
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void bbs_srand(unsigned char *data, int len)
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{
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if((bbs_init & SEED) == 0) {
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mp_init(&bbs_state);
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bbs_init |= SEED;
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}
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mp_read_raw(&bbs_state, (char *)data, len);
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} /* end bbs_srand() */
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unsigned int bbs_rand(void)
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{
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static mp_int modulus;
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unsigned int result = 0, ix;
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if((bbs_init & MODULUS) == 0) {
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mp_init(&modulus);
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mp_read_radix(&modulus, bbs_modulus, 16);
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bbs_init |= MODULUS;
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}
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for(ix = 0; ix < sizeof(unsigned int); ix++) {
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mp_digit d;
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mp_sqrmod(&bbs_state, &modulus, &bbs_state);
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d = DIGIT(&bbs_state, 0);
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result = (result << CHAR_BIT) | (d & UCHAR_MAX);
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}
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return result;
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} /* end bbs_rand() */
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/*------------------------------------------------------------------------*/
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/* HERE THERE BE DRAGONS */
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