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515 lines
16 KiB
515 lines
16 KiB
/* crypto/bn/bn_prime.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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/* ==================================================================== |
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* Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. All advertising materials mentioning features or use of this |
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* software must display the following acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
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* |
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. For written permission, please contact |
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* openssl-core@openssl.org. |
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* |
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* 5. Products derived from this software may not be called "OpenSSL" |
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* nor may "OpenSSL" appear in their names without prior written |
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* permission of the OpenSSL Project. |
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* |
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* 6. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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* OF THE POSSIBILITY OF SUCH DAMAGE. |
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* ==================================================================== |
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* |
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* This product includes cryptographic software written by Eric Young |
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* (eay@cryptsoft.com). This product includes software written by Tim |
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* Hudson (tjh@cryptsoft.com). |
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* |
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*/ |
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#include <stdio.h> |
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#include <time.h> |
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#include "cryptlib.h" |
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#include "bn_lcl.h" |
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#include <openssl/rand.h> |
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/* |
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* NB: these functions have been "upgraded", the deprecated versions (which |
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* are compatibility wrappers using these functions) are in bn_depr.c. - |
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* Geoff |
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*/ |
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/* |
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* The quick sieve algorithm approach to weeding out primes is Philip |
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* Zimmermann's, as implemented in PGP. I have had a read of his comments |
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* and implemented my own version. |
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*/ |
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#include "bn_prime.h" |
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static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, |
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const BIGNUM *a1_odd, int k, BN_CTX *ctx, |
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BN_MONT_CTX *mont); |
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static int probable_prime(BIGNUM *rnd, int bits); |
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static int probable_prime_dh(BIGNUM *rnd, int bits, |
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const BIGNUM *add, const BIGNUM *rem, |
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BN_CTX *ctx); |
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static int probable_prime_dh_safe(BIGNUM *rnd, int bits, const BIGNUM *add, |
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const BIGNUM *rem, BN_CTX *ctx); |
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int BN_GENCB_call(BN_GENCB *cb, int a, int b) |
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{ |
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/* No callback means continue */ |
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if (!cb) |
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return 1; |
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switch (cb->ver) { |
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case 1: |
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/* Deprecated-style callbacks */ |
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if (!cb->cb.cb_1) |
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return 1; |
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cb->cb.cb_1(a, b, cb->arg); |
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return 1; |
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case 2: |
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/* New-style callbacks */ |
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return cb->cb.cb_2(a, b, cb); |
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default: |
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break; |
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} |
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/* Unrecognised callback type */ |
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return 0; |
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} |
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int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, |
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const BIGNUM *add, const BIGNUM *rem, BN_GENCB *cb) |
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{ |
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BIGNUM *t; |
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int found = 0; |
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int i, j, c1 = 0; |
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BN_CTX *ctx; |
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int checks = BN_prime_checks_for_size(bits); |
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ctx = BN_CTX_new(); |
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if (ctx == NULL) |
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goto err; |
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BN_CTX_start(ctx); |
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t = BN_CTX_get(ctx); |
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if (!t) |
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goto err; |
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loop: |
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/* make a random number and set the top and bottom bits */ |
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if (add == NULL) { |
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if (!probable_prime(ret, bits)) |
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goto err; |
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} else { |
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if (safe) { |
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if (!probable_prime_dh_safe(ret, bits, add, rem, ctx)) |
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goto err; |
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} else { |
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if (!probable_prime_dh(ret, bits, add, rem, ctx)) |
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goto err; |
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} |
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} |
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/* if (BN_mod_word(ret,(BN_ULONG)3) == 1) goto loop; */ |
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if (!BN_GENCB_call(cb, 0, c1++)) |
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/* aborted */ |
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goto err; |
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if (!safe) { |
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i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb); |
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if (i == -1) |
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goto err; |
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if (i == 0) |
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goto loop; |
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} else { |
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/* |
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* for "safe prime" generation, check that (p-1)/2 is prime. Since a |
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* prime is odd, We just need to divide by 2 |
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*/ |
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if (!BN_rshift1(t, ret)) |
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goto err; |
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for (i = 0; i < checks; i++) { |
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j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, cb); |
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if (j == -1) |
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goto err; |
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if (j == 0) |
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goto loop; |
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j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, cb); |
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if (j == -1) |
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goto err; |
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if (j == 0) |
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goto loop; |
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if (!BN_GENCB_call(cb, 2, c1 - 1)) |
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goto err; |
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/* We have a safe prime test pass */ |
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} |
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} |
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/* we have a prime :-) */ |
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found = 1; |
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err: |
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if (ctx != NULL) { |
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BN_CTX_end(ctx); |
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BN_CTX_free(ctx); |
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} |
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bn_check_top(ret); |
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return found; |
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} |
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int BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, |
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BN_GENCB *cb) |
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{ |
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return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb); |
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} |
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int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, |
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int do_trial_division, BN_GENCB *cb) |
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{ |
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int i, j, ret = -1; |
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int k; |
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BN_CTX *ctx = NULL; |
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BIGNUM *A1, *A1_odd, *check; /* taken from ctx */ |
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BN_MONT_CTX *mont = NULL; |
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const BIGNUM *A = NULL; |
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if (BN_cmp(a, BN_value_one()) <= 0) |
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return 0; |
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if (checks == BN_prime_checks) |
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checks = BN_prime_checks_for_size(BN_num_bits(a)); |
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/* first look for small factors */ |
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if (!BN_is_odd(a)) |
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/* a is even => a is prime if and only if a == 2 */ |
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return BN_is_word(a, 2); |
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if (do_trial_division) { |
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for (i = 1; i < NUMPRIMES; i++) |
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if (BN_mod_word(a, primes[i]) == 0) |
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return 0; |
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if (!BN_GENCB_call(cb, 1, -1)) |
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goto err; |
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} |
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if (ctx_passed != NULL) |
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ctx = ctx_passed; |
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else if ((ctx = BN_CTX_new()) == NULL) |
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goto err; |
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BN_CTX_start(ctx); |
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/* A := abs(a) */ |
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if (a->neg) { |
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BIGNUM *t; |
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if ((t = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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BN_copy(t, a); |
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t->neg = 0; |
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A = t; |
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} else |
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A = a; |
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A1 = BN_CTX_get(ctx); |
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A1_odd = BN_CTX_get(ctx); |
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check = BN_CTX_get(ctx); |
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if (check == NULL) |
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goto err; |
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/* compute A1 := A - 1 */ |
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if (!BN_copy(A1, A)) |
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goto err; |
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if (!BN_sub_word(A1, 1)) |
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goto err; |
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if (BN_is_zero(A1)) { |
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ret = 0; |
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goto err; |
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} |
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/* write A1 as A1_odd * 2^k */ |
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k = 1; |
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while (!BN_is_bit_set(A1, k)) |
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k++; |
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if (!BN_rshift(A1_odd, A1, k)) |
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goto err; |
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/* Montgomery setup for computations mod A */ |
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mont = BN_MONT_CTX_new(); |
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if (mont == NULL) |
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goto err; |
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if (!BN_MONT_CTX_set(mont, A, ctx)) |
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goto err; |
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for (i = 0; i < checks; i++) { |
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if (!BN_pseudo_rand_range(check, A1)) |
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goto err; |
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if (!BN_add_word(check, 1)) |
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goto err; |
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/* now 1 <= check < A */ |
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j = witness(check, A, A1, A1_odd, k, ctx, mont); |
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if (j == -1) |
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goto err; |
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if (j) { |
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ret = 0; |
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goto err; |
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} |
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if (!BN_GENCB_call(cb, 1, i)) |
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goto err; |
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} |
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ret = 1; |
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err: |
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if (ctx != NULL) { |
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BN_CTX_end(ctx); |
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if (ctx_passed == NULL) |
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BN_CTX_free(ctx); |
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} |
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if (mont != NULL) |
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BN_MONT_CTX_free(mont); |
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return (ret); |
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} |
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static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, |
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const BIGNUM *a1_odd, int k, BN_CTX *ctx, |
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BN_MONT_CTX *mont) |
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{ |
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if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */ |
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return -1; |
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if (BN_is_one(w)) |
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return 0; /* probably prime */ |
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if (BN_cmp(w, a1) == 0) |
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return 0; /* w == -1 (mod a), 'a' is probably prime */ |
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while (--k) { |
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if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */ |
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return -1; |
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if (BN_is_one(w)) |
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return 1; /* 'a' is composite, otherwise a previous 'w' |
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* would have been == -1 (mod 'a') */ |
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if (BN_cmp(w, a1) == 0) |
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return 0; /* w == -1 (mod a), 'a' is probably prime */ |
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} |
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/* |
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* If we get here, 'w' is the (a-1)/2-th power of the original 'w', and |
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* it is neither -1 nor +1 -- so 'a' cannot be prime |
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*/ |
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bn_check_top(w); |
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return 1; |
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} |
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static int probable_prime(BIGNUM *rnd, int bits) |
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{ |
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int i; |
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prime_t mods[NUMPRIMES]; |
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BN_ULONG delta, maxdelta; |
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again: |
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if (!BN_rand(rnd, bits, 1, 1)) |
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return (0); |
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/* we now have a random number 'rand' to test. */ |
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for (i = 1; i < NUMPRIMES; i++) |
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mods[i] = (prime_t) BN_mod_word(rnd, (BN_ULONG)primes[i]); |
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maxdelta = BN_MASK2 - primes[NUMPRIMES - 1]; |
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delta = 0; |
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loop:for (i = 1; i < NUMPRIMES; i++) { |
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/* |
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* check that rnd is not a prime and also that gcd(rnd-1,primes) == 1 |
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* (except for 2) |
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*/ |
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if (((mods[i] + delta) % primes[i]) <= 1) { |
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delta += 2; |
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if (delta > maxdelta) |
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goto again; |
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goto loop; |
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} |
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} |
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if (!BN_add_word(rnd, delta)) |
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return (0); |
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bn_check_top(rnd); |
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return (1); |
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} |
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static int probable_prime_dh(BIGNUM *rnd, int bits, |
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const BIGNUM *add, const BIGNUM *rem, |
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BN_CTX *ctx) |
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{ |
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int i, ret = 0; |
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BIGNUM *t1; |
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BN_CTX_start(ctx); |
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if ((t1 = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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if (!BN_rand(rnd, bits, 0, 1)) |
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goto err; |
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/* we need ((rnd-rem) % add) == 0 */ |
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if (!BN_mod(t1, rnd, add, ctx)) |
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goto err; |
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if (!BN_sub(rnd, rnd, t1)) |
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goto err; |
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if (rem == NULL) { |
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if (!BN_add_word(rnd, 1)) |
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goto err; |
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} else { |
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if (!BN_add(rnd, rnd, rem)) |
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goto err; |
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} |
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/* we now have a random number 'rand' to test. */ |
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loop:for (i = 1; i < NUMPRIMES; i++) { |
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/* check that rnd is a prime */ |
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if (BN_mod_word(rnd, (BN_ULONG)primes[i]) <= 1) { |
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if (!BN_add(rnd, rnd, add)) |
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goto err; |
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goto loop; |
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} |
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} |
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ret = 1; |
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err: |
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BN_CTX_end(ctx); |
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bn_check_top(rnd); |
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return (ret); |
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} |
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|
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static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd, |
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const BIGNUM *rem, BN_CTX *ctx) |
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{ |
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int i, ret = 0; |
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BIGNUM *t1, *qadd, *q; |
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|
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bits--; |
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BN_CTX_start(ctx); |
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t1 = BN_CTX_get(ctx); |
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q = BN_CTX_get(ctx); |
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qadd = BN_CTX_get(ctx); |
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if (qadd == NULL) |
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goto err; |
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|
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if (!BN_rshift1(qadd, padd)) |
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goto err; |
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|
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if (!BN_rand(q, bits, 0, 1)) |
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goto err; |
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|
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/* we need ((rnd-rem) % add) == 0 */ |
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if (!BN_mod(t1, q, qadd, ctx)) |
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goto err; |
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if (!BN_sub(q, q, t1)) |
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goto err; |
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if (rem == NULL) { |
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if (!BN_add_word(q, 1)) |
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goto err; |
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} else { |
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if (!BN_rshift1(t1, rem)) |
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goto err; |
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if (!BN_add(q, q, t1)) |
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goto err; |
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} |
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|
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/* we now have a random number 'rand' to test. */ |
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if (!BN_lshift1(p, q)) |
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goto err; |
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if (!BN_add_word(p, 1)) |
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goto err; |
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|
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loop:for (i = 1; i < NUMPRIMES; i++) { |
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/* check that p and q are prime */ |
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/* |
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* check that for p and q gcd(p-1,primes) == 1 (except for 2) |
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*/ |
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if ((BN_mod_word(p, (BN_ULONG)primes[i]) == 0) || |
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(BN_mod_word(q, (BN_ULONG)primes[i]) == 0)) { |
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if (!BN_add(p, p, padd)) |
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goto err; |
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if (!BN_add(q, q, qadd)) |
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goto err; |
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goto loop; |
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} |
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} |
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ret = 1; |
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err: |
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BN_CTX_end(ctx); |
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bn_check_top(p); |
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return (ret); |
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}
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