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8ed84541 | 1 | /* bn_x931p.c */ |
ae5c8664 MC |
2 | /* |
3 | * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project | |
4 | * 2005. | |
8ed84541 DSH |
5 | */ |
6 | /* ==================================================================== | |
7 | * Copyright (c) 2005 The OpenSSL Project. All rights reserved. | |
8 | * | |
9 | * Redistribution and use in source and binary forms, with or without | |
10 | * modification, are permitted provided that the following conditions | |
11 | * are met: | |
12 | * | |
13 | * 1. Redistributions of source code must retain the above copyright | |
ae5c8664 | 14 | * notice, this list of conditions and the following disclaimer. |
8ed84541 DSH |
15 | * |
16 | * 2. Redistributions in binary form must reproduce the above copyright | |
17 | * notice, this list of conditions and the following disclaimer in | |
18 | * the documentation and/or other materials provided with the | |
19 | * distribution. | |
20 | * | |
21 | * 3. All advertising materials mentioning features or use of this | |
22 | * software must display the following acknowledgment: | |
23 | * "This product includes software developed by the OpenSSL Project | |
24 | * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" | |
25 | * | |
26 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
27 | * endorse or promote products derived from this software without | |
28 | * prior written permission. For written permission, please contact | |
29 | * licensing@OpenSSL.org. | |
30 | * | |
31 | * 5. Products derived from this software may not be called "OpenSSL" | |
32 | * nor may "OpenSSL" appear in their names without prior written | |
33 | * permission of the OpenSSL Project. | |
34 | * | |
35 | * 6. Redistributions of any form whatsoever must retain the following | |
36 | * acknowledgment: | |
37 | * "This product includes software developed by the OpenSSL Project | |
38 | * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" | |
39 | * | |
40 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
41 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
43 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
44 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
45 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
46 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
47 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
49 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
50 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
51 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
52 | * ==================================================================== | |
53 | * | |
54 | * This product includes cryptographic software written by Eric Young | |
55 | * (eay@cryptsoft.com). This product includes software written by Tim | |
56 | * Hudson (tjh@cryptsoft.com). | |
57 | * | |
58 | */ | |
59 | ||
60 | #include <stdio.h> | |
61 | #include <openssl/bn.h> | |
62 | ||
63 | /* X9.31 routines for prime derivation */ | |
64 | ||
ae5c8664 MC |
65 | /* |
66 | * X9.31 prime derivation. This is used to generate the primes pi (p1, p2, | |
67 | * q1, q2) from a parameter Xpi by checking successive odd integers. | |
8ed84541 DSH |
68 | */ |
69 | ||
70 | static int bn_x931_derive_pi(BIGNUM *pi, const BIGNUM *Xpi, BN_CTX *ctx, | |
ae5c8664 MC |
71 | BN_GENCB *cb) |
72 | { | |
73 | int i = 0; | |
74 | if (!BN_copy(pi, Xpi)) | |
75 | return 0; | |
76 | if (!BN_is_odd(pi) && !BN_add_word(pi, 1)) | |
77 | return 0; | |
78 | for (;;) { | |
79 | i++; | |
80 | BN_GENCB_call(cb, 0, i); | |
81 | /* NB 27 MR is specificed in X9.31 */ | |
82 | if (BN_is_prime_fasttest_ex(pi, 27, ctx, 1, cb)) | |
83 | break; | |
84 | if (!BN_add_word(pi, 2)) | |
85 | return 0; | |
86 | } | |
87 | BN_GENCB_call(cb, 2, i); | |
88 | return 1; | |
89 | } | |
90 | ||
91 | /* | |
92 | * This is the main X9.31 prime derivation function. From parameters Xp1, Xp2 | |
93 | * and Xp derive the prime p. If the parameters p1 or p2 are not NULL they | |
94 | * will be returned too: this is needed for testing. | |
8ed84541 DSH |
95 | */ |
96 | ||
97 | int BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2, | |
ae5c8664 MC |
98 | const BIGNUM *Xp, const BIGNUM *Xp1, |
99 | const BIGNUM *Xp2, const BIGNUM *e, BN_CTX *ctx, | |
100 | BN_GENCB *cb) | |
101 | { | |
102 | int ret = 0; | |
8ed84541 | 103 | |
ae5c8664 | 104 | BIGNUM *t, *p1p2, *pm1; |
8ed84541 | 105 | |
ae5c8664 MC |
106 | /* Only even e supported */ |
107 | if (!BN_is_odd(e)) | |
108 | return 0; | |
8ed84541 | 109 | |
ae5c8664 MC |
110 | BN_CTX_start(ctx); |
111 | if (!p1) | |
112 | p1 = BN_CTX_get(ctx); | |
8ed84541 | 113 | |
ae5c8664 MC |
114 | if (!p2) |
115 | p2 = BN_CTX_get(ctx); | |
8ed84541 | 116 | |
ae5c8664 | 117 | t = BN_CTX_get(ctx); |
8ed84541 | 118 | |
ae5c8664 | 119 | p1p2 = BN_CTX_get(ctx); |
8ed84541 | 120 | |
ae5c8664 | 121 | pm1 = BN_CTX_get(ctx); |
8ed84541 | 122 | |
ae5c8664 MC |
123 | if (!bn_x931_derive_pi(p1, Xp1, ctx, cb)) |
124 | goto err; | |
8ed84541 | 125 | |
ae5c8664 MC |
126 | if (!bn_x931_derive_pi(p2, Xp2, ctx, cb)) |
127 | goto err; | |
8ed84541 | 128 | |
ae5c8664 MC |
129 | if (!BN_mul(p1p2, p1, p2, ctx)) |
130 | goto err; | |
8ed84541 | 131 | |
ae5c8664 | 132 | /* First set p to value of Rp */ |
8ed84541 | 133 | |
ae5c8664 MC |
134 | if (!BN_mod_inverse(p, p2, p1, ctx)) |
135 | goto err; | |
8ed84541 | 136 | |
ae5c8664 MC |
137 | if (!BN_mul(p, p, p2, ctx)) |
138 | goto err; | |
8ed84541 | 139 | |
ae5c8664 MC |
140 | if (!BN_mod_inverse(t, p1, p2, ctx)) |
141 | goto err; | |
8ed84541 | 142 | |
ae5c8664 MC |
143 | if (!BN_mul(t, t, p1, ctx)) |
144 | goto err; | |
8ed84541 | 145 | |
ae5c8664 MC |
146 | if (!BN_sub(p, p, t)) |
147 | goto err; | |
8ed84541 | 148 | |
ae5c8664 MC |
149 | if (p->neg && !BN_add(p, p, p1p2)) |
150 | goto err; | |
8ed84541 | 151 | |
ae5c8664 | 152 | /* p now equals Rp */ |
8ed84541 | 153 | |
ae5c8664 MC |
154 | if (!BN_mod_sub(p, p, Xp, p1p2, ctx)) |
155 | goto err; | |
8ed84541 | 156 | |
ae5c8664 MC |
157 | if (!BN_add(p, p, Xp)) |
158 | goto err; | |
8ed84541 | 159 | |
ae5c8664 | 160 | /* p now equals Yp0 */ |
8ed84541 | 161 | |
ae5c8664 MC |
162 | for (;;) { |
163 | int i = 1; | |
164 | BN_GENCB_call(cb, 0, i++); | |
165 | if (!BN_copy(pm1, p)) | |
166 | goto err; | |
167 | if (!BN_sub_word(pm1, 1)) | |
168 | goto err; | |
169 | if (!BN_gcd(t, pm1, e, ctx)) | |
170 | goto err; | |
171 | if (BN_is_one(t) | |
172 | /* | |
173 | * X9.31 specifies 8 MR and 1 Lucas test or any prime test | |
174 | * offering similar or better guarantees 50 MR is considerably | |
175 | * better. | |
176 | */ | |
177 | && BN_is_prime_fasttest_ex(p, 50, ctx, 1, cb)) | |
178 | break; | |
179 | if (!BN_add(p, p, p1p2)) | |
180 | goto err; | |
181 | } | |
8ed84541 | 182 | |
ae5c8664 | 183 | BN_GENCB_call(cb, 3, 0); |
8ed84541 | 184 | |
ae5c8664 | 185 | ret = 1; |
8ed84541 | 186 | |
ae5c8664 | 187 | err: |
8ed84541 | 188 | |
ae5c8664 | 189 | BN_CTX_end(ctx); |
8ed84541 | 190 | |
ae5c8664 MC |
191 | return ret; |
192 | } | |
8ed84541 | 193 | |
ae5c8664 MC |
194 | /* |
195 | * Generate pair of paramters Xp, Xq for X9.31 prime generation. Note: nbits | |
196 | * paramter is sum of number of bits in both. | |
8ed84541 DSH |
197 | */ |
198 | ||
199 | int BN_X931_generate_Xpq(BIGNUM *Xp, BIGNUM *Xq, int nbits, BN_CTX *ctx) | |
ae5c8664 MC |
200 | { |
201 | BIGNUM *t; | |
202 | int i; | |
203 | /* | |
204 | * Number of bits for each prime is of the form 512+128s for s = 0, 1, | |
205 | * ... | |
206 | */ | |
207 | if ((nbits < 1024) || (nbits & 0xff)) | |
208 | return 0; | |
209 | nbits >>= 1; | |
210 | /* | |
211 | * The random value Xp must be between sqrt(2) * 2^(nbits-1) and 2^nbits | |
212 | * - 1. By setting the top two bits we ensure that the lower bound is | |
213 | * exceeded. | |
214 | */ | |
215 | if (!BN_rand(Xp, nbits, 1, 0)) | |
216 | return 0; | |
217 | ||
218 | BN_CTX_start(ctx); | |
219 | t = BN_CTX_get(ctx); | |
220 | ||
221 | for (i = 0; i < 1000; i++) { | |
222 | if (!BN_rand(Xq, nbits, 1, 0)) | |
223 | return 0; | |
224 | /* Check that |Xp - Xq| > 2^(nbits - 100) */ | |
225 | BN_sub(t, Xp, Xq); | |
226 | if (BN_num_bits(t) > (nbits - 100)) | |
227 | break; | |
228 | } | |
229 | ||
230 | BN_CTX_end(ctx); | |
231 | ||
232 | if (i < 1000) | |
233 | return 1; | |
234 | ||
235 | return 0; | |
236 | ||
237 | } | |
238 | ||
239 | /* | |
240 | * Generate primes using X9.31 algorithm. Of the values p, p1, p2, Xp1 and | |
241 | * Xp2 only 'p' needs to be non-NULL. If any of the others are not NULL the | |
242 | * relevant parameter will be stored in it. Due to the fact that |Xp - Xq| > | |
243 | * 2^(nbits - 100) must be satisfied Xp and Xq are generated using the | |
244 | * previous function and supplied as input. | |
8ed84541 DSH |
245 | */ |
246 | ||
247 | int BN_X931_generate_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2, | |
ae5c8664 MC |
248 | BIGNUM *Xp1, BIGNUM *Xp2, |
249 | const BIGNUM *Xp, | |
250 | const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb) | |
251 | { | |
252 | int ret = 0; | |
8ed84541 | 253 | |
ae5c8664 MC |
254 | BN_CTX_start(ctx); |
255 | if (!Xp1) | |
256 | Xp1 = BN_CTX_get(ctx); | |
257 | if (!Xp2) | |
258 | Xp2 = BN_CTX_get(ctx); | |
8ed84541 | 259 | |
ae5c8664 MC |
260 | if (!BN_rand(Xp1, 101, 0, 0)) |
261 | goto error; | |
262 | if (!BN_rand(Xp2, 101, 0, 0)) | |
263 | goto error; | |
264 | if (!BN_X931_derive_prime_ex(p, p1, p2, Xp, Xp1, Xp2, e, ctx, cb)) | |
265 | goto error; | |
8ed84541 | 266 | |
ae5c8664 | 267 | ret = 1; |
8ed84541 | 268 | |
ae5c8664 MC |
269 | error: |
270 | BN_CTX_end(ctx); | |
8ed84541 | 271 | |
ae5c8664 | 272 | return ret; |
8ed84541 | 273 | |
ae5c8664 | 274 | } |