2 * Copyright 2011-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #define OPENSSL_SUPPRESS_DEPRECATED
13 #include <openssl/bn.h>
16 /* X9.31 routines for prime derivation */
19 * X9.31 prime derivation. This is used to generate the primes pi (p1, p2,
20 * q1, q2) from a parameter Xpi by checking successive odd integers.
23 static int bn_x931_derive_pi(BIGNUM *pi, const BIGNUM *Xpi, BN_CTX *ctx,
27 if (!BN_copy(pi, Xpi))
29 if (!BN_is_odd(pi) && !BN_add_word(pi, 1))
33 BN_GENCB_call(cb, 0, i);
34 /* NB 27 MR is specified in X9.31 */
35 is_prime = BN_check_prime(pi, ctx, cb);
40 if (!BN_add_word(pi, 2))
43 BN_GENCB_call(cb, 2, i);
48 * This is the main X9.31 prime derivation function. From parameters Xp1, Xp2
49 * and Xp derive the prime p. If the parameters p1 or p2 are not NULL they
50 * will be returned too: this is needed for testing.
53 int BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
54 const BIGNUM *Xp, const BIGNUM *Xp1,
55 const BIGNUM *Xp2, const BIGNUM *e, BN_CTX *ctx,
60 BIGNUM *t, *p1p2, *pm1;
62 /* Only even e supported */
75 p1p2 = BN_CTX_get(ctx);
77 pm1 = BN_CTX_get(ctx);
82 if (!bn_x931_derive_pi(p1, Xp1, ctx, cb))
85 if (!bn_x931_derive_pi(p2, Xp2, ctx, cb))
88 if (!BN_mul(p1p2, p1, p2, ctx))
91 /* First set p to value of Rp */
93 if (!BN_mod_inverse(p, p2, p1, ctx))
96 if (!BN_mul(p, p, p2, ctx))
99 if (!BN_mod_inverse(t, p1, p2, ctx))
102 if (!BN_mul(t, t, p1, ctx))
105 if (!BN_sub(p, p, t))
108 if (p->neg && !BN_add(p, p, p1p2))
111 /* p now equals Rp */
113 if (!BN_mod_sub(p, p, Xp, p1p2, ctx))
116 if (!BN_add(p, p, Xp))
119 /* p now equals Yp0 */
123 BN_GENCB_call(cb, 0, i++);
124 if (!BN_copy(pm1, p))
126 if (!BN_sub_word(pm1, 1))
128 if (!BN_gcd(t, pm1, e, ctx))
132 * X9.31 specifies 8 MR and 1 Lucas test or any prime test
133 * offering similar or better guarantees 50 MR is considerably
136 int r = BN_check_prime(p, ctx, cb);
142 if (!BN_add(p, p, p1p2))
146 BN_GENCB_call(cb, 3, 0);
158 * Generate pair of parameters Xp, Xq for X9.31 prime generation. Note: nbits
159 * parameter is sum of number of bits in both.
162 int BN_X931_generate_Xpq(BIGNUM *Xp, BIGNUM *Xq, int nbits, BN_CTX *ctx)
167 * Number of bits for each prime is of the form 512+128s for s = 0, 1,
170 if ((nbits < 1024) || (nbits & 0xff))
174 * The random value Xp must be between sqrt(2) * 2^(nbits-1) and 2^nbits
175 * - 1. By setting the top two bits we ensure that the lower bound is
178 if (!BN_priv_rand_ex(Xp, nbits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY, 0,
187 for (i = 0; i < 1000; i++) {
188 if (!BN_priv_rand_ex(Xq, nbits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY, 0,
192 /* Check that |Xp - Xq| > 2^(nbits - 100) */
193 if (!BN_sub(t, Xp, Xq))
195 if (BN_num_bits(t) > (nbits - 100))
212 * Generate primes using X9.31 algorithm. Of the values p, p1, p2, Xp1 and
213 * Xp2 only 'p' needs to be non-NULL. If any of the others are not NULL the
214 * relevant parameter will be stored in it. Due to the fact that |Xp - Xq| >
215 * 2^(nbits - 100) must be satisfied Xp and Xq are generated using the
216 * previous function and supplied as input.
219 int BN_X931_generate_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
220 BIGNUM *Xp1, BIGNUM *Xp2,
222 const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
228 Xp1 = BN_CTX_get(ctx);
230 Xp2 = BN_CTX_get(ctx);
231 if (Xp1 == NULL || Xp2 == NULL)
234 if (!BN_priv_rand_ex(Xp1, 101, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY, 0, ctx))
236 if (!BN_priv_rand_ex(Xp2, 101, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY, 0, ctx))
238 if (!BN_X931_derive_prime_ex(p, p1, p2, Xp, Xp1, Xp2, e, ctx, cb))