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git.ipfire.org Git - thirdparty/openssl.git/blob - crypto/bn/bn_x931p.c
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2 * Copyright 2011-2018 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
11 #include <openssl/bn.h>
14 /* X9.31 routines for prime derivation */
17 * X9.31 prime derivation. This is used to generate the primes pi (p1, p2,
18 * q1, q2) from a parameter Xpi by checking successive odd integers.
21 static int bn_x931_derive_pi(BIGNUM
*pi
, const BIGNUM
*Xpi
, BN_CTX
*ctx
,
25 if (!BN_copy(pi
, Xpi
))
27 if (!BN_is_odd(pi
) && !BN_add_word(pi
, 1))
31 BN_GENCB_call(cb
, 0, i
);
32 /* NB 27 MR is specified in X9.31 */
33 is_prime
= BN_is_prime_fasttest_ex(pi
, 27, ctx
, 1, cb
);
38 if (!BN_add_word(pi
, 2))
41 BN_GENCB_call(cb
, 2, i
);
46 * This is the main X9.31 prime derivation function. From parameters Xp1, Xp2
47 * and Xp derive the prime p. If the parameters p1 or p2 are not NULL they
48 * will be returned too: this is needed for testing.
51 int BN_X931_derive_prime_ex(BIGNUM
*p
, BIGNUM
*p1
, BIGNUM
*p2
,
52 const BIGNUM
*Xp
, const BIGNUM
*Xp1
,
53 const BIGNUM
*Xp2
, const BIGNUM
*e
, BN_CTX
*ctx
,
58 BIGNUM
*t
, *p1p2
, *pm1
;
60 /* Only even e supported */
73 p1p2
= BN_CTX_get(ctx
);
75 pm1
= BN_CTX_get(ctx
);
80 if (!bn_x931_derive_pi(p1
, Xp1
, ctx
, cb
))
83 if (!bn_x931_derive_pi(p2
, Xp2
, ctx
, cb
))
86 if (!BN_mul(p1p2
, p1
, p2
, ctx
))
89 /* First set p to value of Rp */
91 if (!BN_mod_inverse(p
, p2
, p1
, ctx
))
94 if (!BN_mul(p
, p
, p2
, ctx
))
97 if (!BN_mod_inverse(t
, p1
, p2
, ctx
))
100 if (!BN_mul(t
, t
, p1
, ctx
))
103 if (!BN_sub(p
, p
, t
))
106 if (p
->neg
&& !BN_add(p
, p
, p1p2
))
109 /* p now equals Rp */
111 if (!BN_mod_sub(p
, p
, Xp
, p1p2
, ctx
))
114 if (!BN_add(p
, p
, Xp
))
117 /* p now equals Yp0 */
121 BN_GENCB_call(cb
, 0, i
++);
122 if (!BN_copy(pm1
, p
))
124 if (!BN_sub_word(pm1
, 1))
126 if (!BN_gcd(t
, pm1
, e
, ctx
))
130 * X9.31 specifies 8 MR and 1 Lucas test or any prime test
131 * offering similar or better guarantees 50 MR is considerably
134 int r
= BN_is_prime_fasttest_ex(p
, 50, ctx
, 1, cb
);
140 if (!BN_add(p
, p
, p1p2
))
144 BN_GENCB_call(cb
, 3, 0);
156 * Generate pair of parameters Xp, Xq for X9.31 prime generation. Note: nbits
157 * parameter is sum of number of bits in both.
160 int BN_X931_generate_Xpq(BIGNUM
*Xp
, BIGNUM
*Xq
, int nbits
, BN_CTX
*ctx
)
165 * Number of bits for each prime is of the form 512+128s for s = 0, 1,
168 if ((nbits
< 1024) || (nbits
& 0xff))
172 * The random value Xp must be between sqrt(2) * 2^(nbits-1) and 2^nbits
173 * - 1. By setting the top two bits we ensure that the lower bound is
176 if (!BN_priv_rand_ex(Xp
, nbits
, BN_RAND_TOP_TWO
, BN_RAND_BOTTOM_ANY
, ctx
))
184 for (i
= 0; i
< 1000; i
++) {
185 if (!BN_priv_rand_ex(Xq
, nbits
, BN_RAND_TOP_TWO
, BN_RAND_BOTTOM_ANY
,
189 /* Check that |Xp - Xq| > 2^(nbits - 100) */
190 if (!BN_sub(t
, Xp
, Xq
))
192 if (BN_num_bits(t
) > (nbits
- 100))
209 * Generate primes using X9.31 algorithm. Of the values p, p1, p2, Xp1 and
210 * Xp2 only 'p' needs to be non-NULL. If any of the others are not NULL the
211 * relevant parameter will be stored in it. Due to the fact that |Xp - Xq| >
212 * 2^(nbits - 100) must be satisfied Xp and Xq are generated using the
213 * previous function and supplied as input.
216 int BN_X931_generate_prime_ex(BIGNUM
*p
, BIGNUM
*p1
, BIGNUM
*p2
,
217 BIGNUM
*Xp1
, BIGNUM
*Xp2
,
219 const BIGNUM
*e
, BN_CTX
*ctx
, BN_GENCB
*cb
)
225 Xp1
= BN_CTX_get(ctx
);
227 Xp2
= BN_CTX_get(ctx
);
228 if (Xp1
== NULL
|| Xp2
== NULL
)
231 if (!BN_priv_rand_ex(Xp1
, 101, BN_RAND_TOP_ONE
, BN_RAND_BOTTOM_ANY
, ctx
))
233 if (!BN_priv_rand_ex(Xp2
, 101, BN_RAND_TOP_ONE
, BN_RAND_BOTTOM_ANY
, ctx
))
235 if (!BN_X931_derive_prime_ex(p
, p1
, p2
, Xp
, Xp1
, Xp2
, e
, ctx
, cb
))