273 lines
6.8 KiB
C
273 lines
6.8 KiB
C
/* bn_x931p.c */
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/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
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* project 2005.
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*/
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/* ====================================================================
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* Copyright (c) 2005 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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* licensing@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 <openssl/bn.h>
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/* X9.31 routines for prime derivation */
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/* X9.31 prime derivation. This is used to generate the primes pi
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* (p1, p2, q1, q2) from a parameter Xpi by checking successive odd
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* integers.
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*/
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static int bn_x931_derive_pi(BIGNUM *pi, const BIGNUM *Xpi, BN_CTX *ctx,
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BN_GENCB *cb)
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{
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int i = 0;
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if (!BN_copy(pi, Xpi))
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return 0;
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if (!BN_is_odd(pi) && !BN_add_word(pi, 1))
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return 0;
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for(;;)
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{
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i++;
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BN_GENCB_call(cb, 0, i);
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/* NB 27 MR is specificed in X9.31 */
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if (BN_is_prime_fasttest_ex(pi, 27, ctx, 1, cb))
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break;
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if (!BN_add_word(pi, 2))
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return 0;
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}
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BN_GENCB_call(cb, 2, i);
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return 1;
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}
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/* This is the main X9.31 prime derivation function. From parameters
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* Xp1, Xp2 and Xp derive the prime p. If the parameters p1 or p2 are
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* not NULL they will be returned too: this is needed for testing.
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*/
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int BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
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const BIGNUM *Xp, const BIGNUM *Xp1, const BIGNUM *Xp2,
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const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
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{
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int ret = 0;
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BIGNUM *t, *p1p2, *pm1;
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/* Only even e supported */
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if (!BN_is_odd(e))
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return 0;
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BN_CTX_start(ctx);
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if (!p1)
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p1 = BN_CTX_get(ctx);
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if (!p2)
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p2 = BN_CTX_get(ctx);
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t = BN_CTX_get(ctx);
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p1p2 = BN_CTX_get(ctx);
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pm1 = BN_CTX_get(ctx);
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if (!bn_x931_derive_pi(p1, Xp1, ctx, cb))
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goto err;
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if (!bn_x931_derive_pi(p2, Xp2, ctx, cb))
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goto err;
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if (!BN_mul(p1p2, p1, p2, ctx))
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goto err;
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/* First set p to value of Rp */
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if (!BN_mod_inverse(p, p2, p1, ctx))
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goto err;
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if (!BN_mul(p, p, p2, ctx))
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goto err;
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if (!BN_mod_inverse(t, p1, p2, ctx))
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goto err;
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if (!BN_mul(t, t, p1, ctx))
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goto err;
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if (!BN_sub(p, p, t))
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goto err;
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if (p->neg && !BN_add(p, p, p1p2))
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goto err;
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/* p now equals Rp */
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if (!BN_mod_sub(p, p, Xp, p1p2, ctx))
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goto err;
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if (!BN_add(p, p, Xp))
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goto err;
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/* p now equals Yp0 */
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for (;;)
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{
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int i = 1;
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BN_GENCB_call(cb, 0, i++);
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if (!BN_copy(pm1, p))
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goto err;
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if (!BN_sub_word(pm1, 1))
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goto err;
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if (!BN_gcd(t, pm1, e, ctx))
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goto err;
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if (BN_is_one(t)
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/* X9.31 specifies 8 MR and 1 Lucas test or any prime test
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* offering similar or better guarantees 50 MR is considerably
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* better.
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*/
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&& BN_is_prime_fasttest_ex(p, 50, ctx, 1, cb))
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break;
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if (!BN_add(p, p, p1p2))
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goto err;
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}
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BN_GENCB_call(cb, 3, 0);
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ret = 1;
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err:
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BN_CTX_end(ctx);
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return ret;
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}
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/* Generate pair of paramters Xp, Xq for X9.31 prime generation.
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* Note: nbits paramter is sum of number of bits in both.
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*/
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int BN_X931_generate_Xpq(BIGNUM *Xp, BIGNUM *Xq, int nbits, BN_CTX *ctx)
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{
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BIGNUM *t;
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int i;
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/* Number of bits for each prime is of the form
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* 512+128s for s = 0, 1, ...
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*/
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if ((nbits < 1024) || (nbits & 0xff))
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return 0;
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nbits >>= 1;
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/* The random value Xp must be between sqrt(2) * 2^(nbits-1) and
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* 2^nbits - 1. By setting the top two bits we ensure that the lower
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* bound is exceeded.
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*/
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if (!BN_rand(Xp, nbits, 1, 0))
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return 0;
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BN_CTX_start(ctx);
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t = BN_CTX_get(ctx);
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for (i = 0; i < 1000; i++)
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{
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if (!BN_rand(Xq, nbits, 1, 0))
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return 0;
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/* Check that |Xp - Xq| > 2^(nbits - 100) */
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BN_sub(t, Xp, Xq);
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if (BN_num_bits(t) > (nbits - 100))
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break;
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}
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BN_CTX_end(ctx);
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if (i < 1000)
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return 1;
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return 0;
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}
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/* Generate primes using X9.31 algorithm. Of the values p, p1, p2, Xp1
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* and Xp2 only 'p' needs to be non-NULL. If any of the others are not NULL
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* the relevant parameter will be stored in it.
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*
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* Due to the fact that |Xp - Xq| > 2^(nbits - 100) must be satisfied Xp and Xq
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* are generated using the previous function and supplied as input.
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*/
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int BN_X931_generate_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
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BIGNUM *Xp1, BIGNUM *Xp2,
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const BIGNUM *Xp,
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const BIGNUM *e, BN_CTX *ctx,
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BN_GENCB *cb)
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{
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int ret = 0;
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BN_CTX_start(ctx);
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if (!Xp1)
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Xp1 = BN_CTX_get(ctx);
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if (!Xp2)
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Xp2 = BN_CTX_get(ctx);
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if (!BN_rand(Xp1, 101, 0, 0))
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goto error;
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if (!BN_rand(Xp2, 101, 0, 0))
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goto error;
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if (!BN_X931_derive_prime_ex(p, p1, p2, Xp, Xp1, Xp2, e, ctx, cb))
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goto error;
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ret = 1;
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error:
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BN_CTX_end(ctx);
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return ret;
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}
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