155714Skris/* crypto/bn/bn_prime.c */ 255714Skris/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 355714Skris * All rights reserved. 455714Skris * 555714Skris * This package is an SSL implementation written 655714Skris * by Eric Young (eay@cryptsoft.com). 755714Skris * The implementation was written so as to conform with Netscapes SSL. 8280304Sjkim * 955714Skris * This library is free for commercial and non-commercial use as long as 1055714Skris * the following conditions are aheared to. The following conditions 1155714Skris * apply to all code found in this distribution, be it the RC4, RSA, 1255714Skris * lhash, DES, etc., code; not just the SSL code. The SSL documentation 1355714Skris * included with this distribution is covered by the same copyright terms 1455714Skris * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15280304Sjkim * 1655714Skris * Copyright remains Eric Young's, and as such any Copyright notices in 1755714Skris * the code are not to be removed. 1855714Skris * If this package is used in a product, Eric Young should be given attribution 1955714Skris * as the author of the parts of the library used. 2055714Skris * This can be in the form of a textual message at program startup or 2155714Skris * in documentation (online or textual) provided with the package. 22280304Sjkim * 2355714Skris * Redistribution and use in source and binary forms, with or without 2455714Skris * modification, are permitted provided that the following conditions 2555714Skris * are met: 2655714Skris * 1. Redistributions of source code must retain the copyright 2755714Skris * notice, this list of conditions and the following disclaimer. 2855714Skris * 2. Redistributions in binary form must reproduce the above copyright 2955714Skris * notice, this list of conditions and the following disclaimer in the 3055714Skris * documentation and/or other materials provided with the distribution. 3155714Skris * 3. All advertising materials mentioning features or use of this software 3255714Skris * must display the following acknowledgement: 3355714Skris * "This product includes cryptographic software written by 3455714Skris * Eric Young (eay@cryptsoft.com)" 3555714Skris * The word 'cryptographic' can be left out if the rouines from the library 3655714Skris * being used are not cryptographic related :-). 37280304Sjkim * 4. If you include any Windows specific code (or a derivative thereof) from 3855714Skris * the apps directory (application code) you must include an acknowledgement: 3955714Skris * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40280304Sjkim * 4155714Skris * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 4255714Skris * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 4355714Skris * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 4455714Skris * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 4555714Skris * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 4655714Skris * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 4755714Skris * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 4855714Skris * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 4955714Skris * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 5055714Skris * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 5155714Skris * SUCH DAMAGE. 52280304Sjkim * 5355714Skris * The licence and distribution terms for any publically available version or 5455714Skris * derivative of this code cannot be changed. i.e. this code cannot simply be 5555714Skris * copied and put under another distribution licence 5655714Skris * [including the GNU Public Licence.] 5755714Skris */ 5859191Skris/* ==================================================================== 59109998Smarkm * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. 6059191Skris * 6159191Skris * Redistribution and use in source and binary forms, with or without 6259191Skris * modification, are permitted provided that the following conditions 6359191Skris * are met: 6459191Skris * 6559191Skris * 1. Redistributions of source code must retain the above copyright 66280304Sjkim * notice, this list of conditions and the following disclaimer. 6759191Skris * 6859191Skris * 2. Redistributions in binary form must reproduce the above copyright 6959191Skris * notice, this list of conditions and the following disclaimer in 7059191Skris * the documentation and/or other materials provided with the 7159191Skris * distribution. 7259191Skris * 7359191Skris * 3. All advertising materials mentioning features or use of this 7459191Skris * software must display the following acknowledgment: 7559191Skris * "This product includes software developed by the OpenSSL Project 7659191Skris * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 7759191Skris * 7859191Skris * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 7959191Skris * endorse or promote products derived from this software without 8059191Skris * prior written permission. For written permission, please contact 8159191Skris * openssl-core@openssl.org. 8259191Skris * 8359191Skris * 5. Products derived from this software may not be called "OpenSSL" 8459191Skris * nor may "OpenSSL" appear in their names without prior written 8559191Skris * permission of the OpenSSL Project. 8659191Skris * 8759191Skris * 6. Redistributions of any form whatsoever must retain the following 8859191Skris * acknowledgment: 8959191Skris * "This product includes software developed by the OpenSSL Project 9059191Skris * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 9159191Skris * 9259191Skris * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 9359191Skris * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 9459191Skris * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 9559191Skris * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 9659191Skris * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 9759191Skris * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 9859191Skris * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 9959191Skris * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 10059191Skris * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 10159191Skris * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 10259191Skris * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 10359191Skris * OF THE POSSIBILITY OF SUCH DAMAGE. 10459191Skris * ==================================================================== 10559191Skris * 10659191Skris * This product includes cryptographic software written by Eric Young 10759191Skris * (eay@cryptsoft.com). This product includes software written by Tim 10859191Skris * Hudson (tjh@cryptsoft.com). 10959191Skris * 11059191Skris */ 11155714Skris 11255714Skris#include <stdio.h> 11355714Skris#include <time.h> 11455714Skris#include "cryptlib.h" 11555714Skris#include "bn_lcl.h" 11655714Skris#include <openssl/rand.h> 11755714Skris 118280304Sjkim/* 119280304Sjkim * NB: these functions have been "upgraded", the deprecated versions (which 120280304Sjkim * are compatibility wrappers using these functions) are in bn_depr.c. - 121280304Sjkim * Geoff 122160814Ssimon */ 123160814Ssimon 124280304Sjkim/* 125280304Sjkim * The quick sieve algorithm approach to weeding out primes is Philip 126280304Sjkim * Zimmermann's, as implemented in PGP. I have had a read of his comments 127280304Sjkim * and implemented my own version. 12855714Skris */ 12955714Skris#include "bn_prime.h" 13055714Skris 13159191Skrisstatic int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, 132280304Sjkim const BIGNUM *a1_odd, int k, BN_CTX *ctx, 133280304Sjkim BN_MONT_CTX *mont); 13455714Skrisstatic int probable_prime(BIGNUM *rnd, int bits); 13555714Skrisstatic int probable_prime_dh(BIGNUM *rnd, int bits, 136280304Sjkim const BIGNUM *add, const BIGNUM *rem, 137280304Sjkim BN_CTX *ctx); 138280304Sjkimstatic int probable_prime_dh_safe(BIGNUM *rnd, int bits, const BIGNUM *add, 139280304Sjkim const BIGNUM *rem, BN_CTX *ctx); 14059191Skris 141160814Ssimonint BN_GENCB_call(BN_GENCB *cb, int a, int b) 142280304Sjkim{ 143280304Sjkim /* No callback means continue */ 144280304Sjkim if (!cb) 145280304Sjkim return 1; 146280304Sjkim switch (cb->ver) { 147280304Sjkim case 1: 148280304Sjkim /* Deprecated-style callbacks */ 149280304Sjkim if (!cb->cb.cb_1) 150280304Sjkim return 1; 151280304Sjkim cb->cb.cb_1(a, b, cb->arg); 152280304Sjkim return 1; 153280304Sjkim case 2: 154280304Sjkim /* New-style callbacks */ 155280304Sjkim return cb->cb.cb_2(a, b, cb); 156280304Sjkim default: 157280304Sjkim break; 158280304Sjkim } 159280304Sjkim /* Unrecognised callback type */ 160280304Sjkim return 0; 161280304Sjkim} 162160814Ssimon 163160814Ssimonint BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, 164280304Sjkim const BIGNUM *add, const BIGNUM *rem, BN_GENCB *cb) 165280304Sjkim{ 166280304Sjkim BIGNUM *t; 167280304Sjkim int found = 0; 168280304Sjkim int i, j, c1 = 0; 169280304Sjkim BN_CTX *ctx; 170280304Sjkim int checks = BN_prime_checks_for_size(bits); 17155714Skris 172280304Sjkim ctx = BN_CTX_new(); 173280304Sjkim if (ctx == NULL) 174280304Sjkim goto err; 175280304Sjkim BN_CTX_start(ctx); 176280304Sjkim t = BN_CTX_get(ctx); 177280304Sjkim if (!t) 178280304Sjkim goto err; 179280304Sjkim loop: 180280304Sjkim /* make a random number and set the top and bottom bits */ 181280304Sjkim if (add == NULL) { 182280304Sjkim if (!probable_prime(ret, bits)) 183280304Sjkim goto err; 184280304Sjkim } else { 185280304Sjkim if (safe) { 186280304Sjkim if (!probable_prime_dh_safe(ret, bits, add, rem, ctx)) 187280304Sjkim goto err; 188280304Sjkim } else { 189280304Sjkim if (!probable_prime_dh(ret, bits, add, rem, ctx)) 190280304Sjkim goto err; 191280304Sjkim } 192280304Sjkim } 193280304Sjkim /* if (BN_mod_word(ret,(BN_ULONG)3) == 1) goto loop; */ 194280304Sjkim if (!BN_GENCB_call(cb, 0, c1++)) 195280304Sjkim /* aborted */ 196280304Sjkim goto err; 19755714Skris 198280304Sjkim if (!safe) { 199280304Sjkim i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb); 200280304Sjkim if (i == -1) 201280304Sjkim goto err; 202280304Sjkim if (i == 0) 203280304Sjkim goto loop; 204280304Sjkim } else { 205280304Sjkim /* 206280304Sjkim * for "safe prime" generation, check that (p-1)/2 is prime. Since a 207280304Sjkim * prime is odd, We just need to divide by 2 208280304Sjkim */ 209280304Sjkim if (!BN_rshift1(t, ret)) 210280304Sjkim goto err; 21155714Skris 212280304Sjkim for (i = 0; i < checks; i++) { 213280304Sjkim j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, cb); 214280304Sjkim if (j == -1) 215280304Sjkim goto err; 216280304Sjkim if (j == 0) 217280304Sjkim goto loop; 21855714Skris 219280304Sjkim j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, cb); 220280304Sjkim if (j == -1) 221280304Sjkim goto err; 222280304Sjkim if (j == 0) 223280304Sjkim goto loop; 22455714Skris 225280304Sjkim if (!BN_GENCB_call(cb, 2, c1 - 1)) 226280304Sjkim goto err; 227280304Sjkim /* We have a safe prime test pass */ 228280304Sjkim } 229280304Sjkim } 230280304Sjkim /* we have a prime :-) */ 231280304Sjkim found = 1; 232280304Sjkim err: 233280304Sjkim if (ctx != NULL) { 234280304Sjkim BN_CTX_end(ctx); 235280304Sjkim BN_CTX_free(ctx); 236280304Sjkim } 237280304Sjkim bn_check_top(ret); 238280304Sjkim return found; 239280304Sjkim} 24055714Skris 241280304Sjkimint BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, 242280304Sjkim BN_GENCB *cb) 243280304Sjkim{ 244280304Sjkim return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb); 245280304Sjkim} 24655714Skris 247160814Ssimonint BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, 248280304Sjkim int do_trial_division, BN_GENCB *cb) 249280304Sjkim{ 250280304Sjkim int i, j, ret = -1; 251280304Sjkim int k; 252280304Sjkim BN_CTX *ctx = NULL; 253280304Sjkim BIGNUM *A1, *A1_odd, *check; /* taken from ctx */ 254280304Sjkim BN_MONT_CTX *mont = NULL; 255280304Sjkim const BIGNUM *A = NULL; 25659191Skris 257280304Sjkim if (BN_cmp(a, BN_value_one()) <= 0) 258280304Sjkim return 0; 25959191Skris 260280304Sjkim if (checks == BN_prime_checks) 261280304Sjkim checks = BN_prime_checks_for_size(BN_num_bits(a)); 26259191Skris 263280304Sjkim /* first look for small factors */ 264280304Sjkim if (!BN_is_odd(a)) 265280304Sjkim /* a is even => a is prime if and only if a == 2 */ 266280304Sjkim return BN_is_word(a, 2); 267280304Sjkim if (do_trial_division) { 268280304Sjkim for (i = 1; i < NUMPRIMES; i++) 269280304Sjkim if (BN_mod_word(a, primes[i]) == 0) 270280304Sjkim return 0; 271280304Sjkim if (!BN_GENCB_call(cb, 1, -1)) 272280304Sjkim goto err; 273280304Sjkim } 27455714Skris 275280304Sjkim if (ctx_passed != NULL) 276280304Sjkim ctx = ctx_passed; 277280304Sjkim else if ((ctx = BN_CTX_new()) == NULL) 278280304Sjkim goto err; 279280304Sjkim BN_CTX_start(ctx); 28055714Skris 281280304Sjkim /* A := abs(a) */ 282280304Sjkim if (a->neg) { 283280304Sjkim BIGNUM *t; 284280304Sjkim if ((t = BN_CTX_get(ctx)) == NULL) 285280304Sjkim goto err; 286280304Sjkim BN_copy(t, a); 287280304Sjkim t->neg = 0; 288280304Sjkim A = t; 289280304Sjkim } else 290280304Sjkim A = a; 291280304Sjkim A1 = BN_CTX_get(ctx); 292280304Sjkim A1_odd = BN_CTX_get(ctx); 293280304Sjkim check = BN_CTX_get(ctx); 294280304Sjkim if (check == NULL) 295280304Sjkim goto err; 29655714Skris 297280304Sjkim /* compute A1 := A - 1 */ 298280304Sjkim if (!BN_copy(A1, A)) 299280304Sjkim goto err; 300280304Sjkim if (!BN_sub_word(A1, 1)) 301280304Sjkim goto err; 302280304Sjkim if (BN_is_zero(A1)) { 303280304Sjkim ret = 0; 304280304Sjkim goto err; 305280304Sjkim } 30655714Skris 307280304Sjkim /* write A1 as A1_odd * 2^k */ 308280304Sjkim k = 1; 309280304Sjkim while (!BN_is_bit_set(A1, k)) 310280304Sjkim k++; 311280304Sjkim if (!BN_rshift(A1_odd, A1, k)) 312280304Sjkim goto err; 31359191Skris 314280304Sjkim /* Montgomery setup for computations mod A */ 315280304Sjkim mont = BN_MONT_CTX_new(); 316280304Sjkim if (mont == NULL) 317280304Sjkim goto err; 318280304Sjkim if (!BN_MONT_CTX_set(mont, A, ctx)) 319280304Sjkim goto err; 32059191Skris 321280304Sjkim for (i = 0; i < checks; i++) { 322280304Sjkim if (!BN_pseudo_rand_range(check, A1)) 323280304Sjkim goto err; 324280304Sjkim if (!BN_add_word(check, 1)) 325280304Sjkim goto err; 326280304Sjkim /* now 1 <= check < A */ 32755714Skris 328280304Sjkim j = witness(check, A, A1, A1_odd, k, ctx, mont); 329280304Sjkim if (j == -1) 330280304Sjkim goto err; 331280304Sjkim if (j) { 332280304Sjkim ret = 0; 333280304Sjkim goto err; 334280304Sjkim } 335280304Sjkim if (!BN_GENCB_call(cb, 1, i)) 336280304Sjkim goto err; 337280304Sjkim } 338280304Sjkim ret = 1; 339280304Sjkim err: 340280304Sjkim if (ctx != NULL) { 341280304Sjkim BN_CTX_end(ctx); 342280304Sjkim if (ctx_passed == NULL) 343280304Sjkim BN_CTX_free(ctx); 344280304Sjkim } 345280304Sjkim if (mont != NULL) 346280304Sjkim BN_MONT_CTX_free(mont); 347280304Sjkim 348280304Sjkim return (ret); 349280304Sjkim} 350280304Sjkim 35159191Skrisstatic int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, 352280304Sjkim const BIGNUM *a1_odd, int k, BN_CTX *ctx, 353280304Sjkim BN_MONT_CTX *mont) 354280304Sjkim{ 355280304Sjkim if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */ 356280304Sjkim return -1; 357280304Sjkim if (BN_is_one(w)) 358280304Sjkim return 0; /* probably prime */ 359280304Sjkim if (BN_cmp(w, a1) == 0) 360280304Sjkim return 0; /* w == -1 (mod a), 'a' is probably prime */ 361280304Sjkim while (--k) { 362280304Sjkim if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */ 363280304Sjkim return -1; 364280304Sjkim if (BN_is_one(w)) 365280304Sjkim return 1; /* 'a' is composite, otherwise a previous 'w' 366280304Sjkim * would have been == -1 (mod 'a') */ 367280304Sjkim if (BN_cmp(w, a1) == 0) 368280304Sjkim return 0; /* w == -1 (mod a), 'a' is probably prime */ 369280304Sjkim } 370280304Sjkim /* 371280304Sjkim * If we get here, 'w' is the (a-1)/2-th power of the original 'w', and 372280304Sjkim * it is neither -1 nor +1 -- so 'a' cannot be prime 373280304Sjkim */ 374280304Sjkim bn_check_top(w); 375280304Sjkim return 1; 376280304Sjkim} 37755714Skris 37855714Skrisstatic int probable_prime(BIGNUM *rnd, int bits) 379280304Sjkim{ 380280304Sjkim int i; 381280304Sjkim prime_t mods[NUMPRIMES]; 382280304Sjkim BN_ULONG delta, maxdelta; 38355714Skris 384280304Sjkim again: 385280304Sjkim if (!BN_rand(rnd, bits, 1, 1)) 386280304Sjkim return (0); 387280304Sjkim /* we now have a random number 'rand' to test. */ 388280304Sjkim for (i = 1; i < NUMPRIMES; i++) 389280304Sjkim mods[i] = (prime_t) BN_mod_word(rnd, (BN_ULONG)primes[i]); 390280304Sjkim maxdelta = BN_MASK2 - primes[NUMPRIMES - 1]; 391280304Sjkim delta = 0; 392280304Sjkim loop:for (i = 1; i < NUMPRIMES; i++) { 393280304Sjkim /* 394280304Sjkim * check that rnd is not a prime and also that gcd(rnd-1,primes) == 1 395280304Sjkim * (except for 2) 396280304Sjkim */ 397280304Sjkim if (((mods[i] + delta) % primes[i]) <= 1) { 398280304Sjkim delta += 2; 399280304Sjkim if (delta > maxdelta) 400280304Sjkim goto again; 401280304Sjkim goto loop; 402280304Sjkim } 403280304Sjkim } 404280304Sjkim if (!BN_add_word(rnd, delta)) 405280304Sjkim return (0); 406280304Sjkim bn_check_top(rnd); 407280304Sjkim return (1); 408280304Sjkim} 40955714Skris 410109998Smarkmstatic int probable_prime_dh(BIGNUM *rnd, int bits, 411280304Sjkim const BIGNUM *add, const BIGNUM *rem, 412280304Sjkim BN_CTX *ctx) 413280304Sjkim{ 414280304Sjkim int i, ret = 0; 415280304Sjkim BIGNUM *t1; 41655714Skris 417280304Sjkim BN_CTX_start(ctx); 418280304Sjkim if ((t1 = BN_CTX_get(ctx)) == NULL) 419280304Sjkim goto err; 42055714Skris 421280304Sjkim if (!BN_rand(rnd, bits, 0, 1)) 422280304Sjkim goto err; 42355714Skris 424280304Sjkim /* we need ((rnd-rem) % add) == 0 */ 42555714Skris 426280304Sjkim if (!BN_mod(t1, rnd, add, ctx)) 427280304Sjkim goto err; 428280304Sjkim if (!BN_sub(rnd, rnd, t1)) 429280304Sjkim goto err; 430280304Sjkim if (rem == NULL) { 431280304Sjkim if (!BN_add_word(rnd, 1)) 432280304Sjkim goto err; 433280304Sjkim } else { 434280304Sjkim if (!BN_add(rnd, rnd, rem)) 435280304Sjkim goto err; 436280304Sjkim } 43755714Skris 438280304Sjkim /* we now have a random number 'rand' to test. */ 43955714Skris 440280304Sjkim loop:for (i = 1; i < NUMPRIMES; i++) { 441280304Sjkim /* check that rnd is a prime */ 442280304Sjkim if (BN_mod_word(rnd, (BN_ULONG)primes[i]) <= 1) { 443280304Sjkim if (!BN_add(rnd, rnd, add)) 444280304Sjkim goto err; 445280304Sjkim goto loop; 446280304Sjkim } 447280304Sjkim } 448280304Sjkim ret = 1; 449280304Sjkim err: 450280304Sjkim BN_CTX_end(ctx); 451280304Sjkim bn_check_top(rnd); 452280304Sjkim return (ret); 453280304Sjkim} 45455714Skris 455109998Smarkmstatic int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd, 456280304Sjkim const BIGNUM *rem, BN_CTX *ctx) 457280304Sjkim{ 458280304Sjkim int i, ret = 0; 459280304Sjkim BIGNUM *t1, *qadd, *q; 46055714Skris 461280304Sjkim bits--; 462280304Sjkim BN_CTX_start(ctx); 463280304Sjkim t1 = BN_CTX_get(ctx); 464280304Sjkim q = BN_CTX_get(ctx); 465280304Sjkim qadd = BN_CTX_get(ctx); 466280304Sjkim if (qadd == NULL) 467280304Sjkim goto err; 46855714Skris 469280304Sjkim if (!BN_rshift1(qadd, padd)) 470280304Sjkim goto err; 47155714Skris 472280304Sjkim if (!BN_rand(q, bits, 0, 1)) 473280304Sjkim goto err; 47455714Skris 475280304Sjkim /* we need ((rnd-rem) % add) == 0 */ 476280304Sjkim if (!BN_mod(t1, q, qadd, ctx)) 477280304Sjkim goto err; 478280304Sjkim if (!BN_sub(q, q, t1)) 479280304Sjkim goto err; 480280304Sjkim if (rem == NULL) { 481280304Sjkim if (!BN_add_word(q, 1)) 482280304Sjkim goto err; 483280304Sjkim } else { 484280304Sjkim if (!BN_rshift1(t1, rem)) 485280304Sjkim goto err; 486280304Sjkim if (!BN_add(q, q, t1)) 487280304Sjkim goto err; 488280304Sjkim } 48955714Skris 490280304Sjkim /* we now have a random number 'rand' to test. */ 491280304Sjkim if (!BN_lshift1(p, q)) 492280304Sjkim goto err; 493280304Sjkim if (!BN_add_word(p, 1)) 494280304Sjkim goto err; 495280304Sjkim 496280304Sjkim loop:for (i = 1; i < NUMPRIMES; i++) { 497280304Sjkim /* check that p and q are prime */ 498280304Sjkim /* 499280304Sjkim * check that for p and q gcd(p-1,primes) == 1 (except for 2) 500280304Sjkim */ 501280304Sjkim if ((BN_mod_word(p, (BN_ULONG)primes[i]) == 0) || 502280304Sjkim (BN_mod_word(q, (BN_ULONG)primes[i]) == 0)) { 503280304Sjkim if (!BN_add(p, p, padd)) 504280304Sjkim goto err; 505280304Sjkim if (!BN_add(q, q, qadd)) 506280304Sjkim goto err; 507280304Sjkim goto loop; 508280304Sjkim } 509280304Sjkim } 510280304Sjkim ret = 1; 511280304Sjkim err: 512280304Sjkim BN_CTX_end(ctx); 513280304Sjkim bn_check_top(p); 514280304Sjkim return (ret); 515280304Sjkim} 516