1 /* crypto/dsa/dsa_gen.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
60 * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
61 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB
64 #define xxxHASH EVP_sha1()
66 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
69 #include "internal/cryptlib.h"
70 #include <openssl/evp.h>
71 #include <openssl/bn.h>
72 #include <openssl/rand.h>
73 #include <openssl/sha.h>
77 int DSA_generate_parameters_ex(DSA *ret, int bits,
78 const unsigned char *seed_in, int seed_len,
79 int *counter_ret, unsigned long *h_ret,
82 if (ret->meth->dsa_paramgen)
83 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
84 counter_ret, h_ret, cb);
86 const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
87 size_t qbits = EVP_MD_size(evpmd) * 8;
89 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
90 seed_in, seed_len, NULL, counter_ret,
95 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
96 const EVP_MD *evpmd, const unsigned char *seed_in,
97 size_t seed_len, unsigned char *seed_out,
98 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
101 unsigned char seed[SHA256_DIGEST_LENGTH];
102 unsigned char md[SHA256_DIGEST_LENGTH];
103 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
104 BIGNUM *r0, *W, *X, *c, *test;
105 BIGNUM *g = NULL, *q = NULL, *p = NULL;
106 BN_MONT_CTX *mont = NULL;
107 int i, k, n = 0, m = 0, qsize = qbits >> 3;
113 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
114 qsize != SHA256_DIGEST_LENGTH)
119 /* use SHA1 as default */
125 bits = (bits + 63) / 64 * 64;
127 if (seed_in != NULL) {
128 if (seed_len < (size_t)qsize)
130 if (seed_len > (size_t)qsize) {
131 /* Only consume as much seed as is expected. */
134 memcpy(seed, seed_in, seed_len);
137 if ((mont = BN_MONT_CTX_new()) == NULL)
140 if ((ctx = BN_CTX_new()) == NULL)
145 r0 = BN_CTX_get(ctx);
152 test = BN_CTX_get(ctx);
154 if (!BN_lshift(test, BN_value_one(), bits - 1))
158 for (;;) { /* find q */
159 int use_random_seed = (seed_in == NULL);
162 if (!BN_GENCB_call(cb, 0, m++))
165 if (use_random_seed) {
166 if (RAND_bytes(seed, qsize) <= 0)
169 /* If we come back through, use random seed next time. */
172 memcpy(buf, seed, qsize);
173 memcpy(buf2, seed, qsize);
174 /* precompute "SEED + 1" for step 7: */
175 for (i = qsize - 1; i >= 0; i--) {
182 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
184 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
186 for (i = 0; i < qsize; i++)
191 md[qsize - 1] |= 0x01;
192 if (!BN_bin2bn(md, qsize, q))
196 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
197 use_random_seed, cb);
203 /* do a callback call */
207 if (!BN_GENCB_call(cb, 2, 0))
209 if (!BN_GENCB_call(cb, 3, 0))
216 n = (bits - 1) / 160;
219 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
224 /* now 'buf' contains "SEED + offset - 1" */
225 for (k = 0; k <= n; k++) {
227 * obtain "SEED + offset + k" by incrementing:
229 for (i = qsize - 1; i >= 0; i--) {
235 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
239 if (!BN_bin2bn(md, qsize, r0))
241 if (!BN_lshift(r0, r0, (qsize << 3) * k))
243 if (!BN_add(W, W, r0))
248 if (!BN_mask_bits(W, bits - 1))
252 if (!BN_add(X, X, test))
256 if (!BN_lshift1(r0, q))
258 if (!BN_mod(c, X, r0, ctx))
260 if (!BN_sub(r0, c, BN_value_one()))
262 if (!BN_sub(p, X, r0))
266 if (BN_cmp(p, test) >= 0) {
268 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
270 goto end; /* found it */
277 /* "offset = offset + n + 1" */
285 if (!BN_GENCB_call(cb, 2, 1))
288 /* We now need to generate g */
290 if (!BN_sub(test, p, BN_value_one()))
292 if (!BN_div(r0, NULL, test, q, ctx))
295 if (!BN_set_word(test, h))
297 if (!BN_MONT_CTX_set(mont, p, ctx))
302 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
306 if (!BN_add(test, test, BN_value_one()))
311 if (!BN_GENCB_call(cb, 3, 1))
323 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
327 if (counter_ret != NULL)
328 *counter_ret = counter;
332 memcpy(seed_out, seed, qsize);
337 BN_MONT_CTX_free(mont);
342 * This is a parameter generation algorithm for the DSA2 algorithm as
343 * described in FIPS 186-3.
346 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
347 const EVP_MD *evpmd, const unsigned char *seed_in,
348 size_t seed_len, int idx, unsigned char *seed_out,
349 int *counter_ret, unsigned long *h_ret,
353 unsigned char *seed = NULL, *seed_tmp = NULL;
354 unsigned char md[EVP_MAX_MD_SIZE];
356 BIGNUM *r0, *W, *X, *c, *test;
357 BIGNUM *g = NULL, *q = NULL, *p = NULL;
358 BN_MONT_CTX *mont = NULL;
359 int i, k, n = 0, m = 0, qsize = N >> 3;
366 EVP_MD_CTX_init(&mctx);
372 evpmd = EVP_sha224();
374 evpmd = EVP_sha256();
377 mdsize = M_EVP_MD_size(evpmd);
378 /* If unverificable g generation only don't need seed */
379 if (!ret->p || !ret->q || idx >= 0) {
383 seed = OPENSSL_malloc(seed_len);
388 seed_tmp = OPENSSL_malloc(seed_len);
390 if (seed == NULL || seed_tmp == NULL)
394 memcpy(seed, seed_in, seed_len);
398 if ((ctx = BN_CTX_new()) == NULL)
401 if ((mont = BN_MONT_CTX_new()) == NULL)
405 r0 = BN_CTX_get(ctx);
410 test = BN_CTX_get(ctx);
412 /* if p, q already supplied generate g only */
413 if (ret->p && ret->q) {
417 memcpy(seed_tmp, seed, seed_len);
424 if (!BN_lshift(test, BN_value_one(), L - 1))
427 for (;;) { /* find q */
430 if (!BN_GENCB_call(cb, 0, m++))
434 if (RAND_bytes(seed, seed_len) <= 0)
438 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
440 /* Take least significant bits of md */
442 pmd = md + mdsize - qsize;
447 memset(md + mdsize, 0, qsize - mdsize);
451 pmd[qsize - 1] |= 0x01;
452 if (!BN_bin2bn(pmd, qsize, q))
456 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
457 seed_in ? 1 : 0, cb);
462 /* Provided seed didn't produce a prime: error */
465 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
469 /* do a callback call */
472 /* Copy seed to seed_out before we mess with it */
474 memcpy(seed_out, seed, seed_len);
476 if (!BN_GENCB_call(cb, 2, 0))
478 if (!BN_GENCB_call(cb, 3, 0))
485 n = (L - 1) / (mdsize << 3);
488 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
493 /* now 'buf' contains "SEED + offset - 1" */
494 for (k = 0; k <= n; k++) {
496 * obtain "SEED + offset + k" by incrementing:
498 for (i = seed_len - 1; i >= 0; i--) {
504 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
508 if (!BN_bin2bn(md, mdsize, r0))
510 if (!BN_lshift(r0, r0, (mdsize << 3) * k))
512 if (!BN_add(W, W, r0))
517 if (!BN_mask_bits(W, L - 1))
521 if (!BN_add(X, X, test))
525 if (!BN_lshift1(r0, q))
527 if (!BN_mod(c, X, r0, ctx))
529 if (!BN_sub(r0, c, BN_value_one()))
531 if (!BN_sub(p, X, r0))
535 if (BN_cmp(p, test) >= 0) {
537 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
539 goto end; /* found it */
546 /* "offset = offset + n + 1" */
549 if (counter >= (int)(4 * L))
554 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
559 if (!BN_GENCB_call(cb, 2, 1))
564 /* We now need to generate g */
566 if (!BN_sub(test, p, BN_value_one()))
568 if (!BN_div(r0, NULL, test, q, ctx))
572 if (!BN_set_word(test, h))
576 if (!BN_MONT_CTX_set(mont, p, ctx))
580 static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
583 md[1] = (h >> 8) & 0xff;
585 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
587 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
589 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
591 if (!EVP_DigestUpdate(&mctx, md, 3))
593 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
595 if (!BN_bin2bn(md, mdsize, test))
599 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
603 if (idx < 0 && !BN_add(test, test, BN_value_one()))
606 if (idx >= 0 && h > 0xffff)
610 if (!BN_GENCB_call(cb, 3, 1))
626 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
630 if (counter_ret != NULL)
631 *counter_ret = counter;
636 if (seed_out != seed_tmp)
637 OPENSSL_free(seed_tmp);
641 BN_MONT_CTX_free(mont);
642 EVP_MD_CTX_cleanup(&mctx);
646 int dsa_paramgen_check_g(DSA *dsa)
650 BN_MONT_CTX *mont = NULL;
656 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
658 if (BN_cmp(dsa->g, dsa->p) >= 0)
660 tmp = BN_CTX_get(ctx);
663 if ((mont = BN_MONT_CTX_new()) == NULL)
665 if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
667 /* Work out g^q mod p */
668 if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
670 if (!BN_cmp(tmp, BN_value_one()))
676 BN_MONT_CTX_free(mont);