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);
87 size_t qbits = bits >= 2048 ? 256 : 160;
97 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
98 seed_in, seed_len, NULL, counter_ret,
103 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
104 const EVP_MD *evpmd, const unsigned char *seed_in,
105 size_t seed_len, unsigned char *seed_out,
106 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
109 unsigned char seed[SHA256_DIGEST_LENGTH];
110 unsigned char md[SHA256_DIGEST_LENGTH];
111 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
112 BIGNUM *r0, *W, *X, *c, *test;
113 BIGNUM *g = NULL, *q = NULL, *p = NULL;
114 BN_MONT_CTX *mont = NULL;
115 int i, k, n = 0, m = 0, qsize = qbits >> 3;
121 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
122 qsize != SHA256_DIGEST_LENGTH)
127 /* use SHA1 as default */
133 bits = (bits + 63) / 64 * 64;
136 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
139 if (seed_len && (seed_len < (size_t)qsize))
140 seed_in = NULL; /* seed buffer too small -- ignore */
141 if (seed_len > (size_t)qsize)
142 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger
143 * SEED, but our internal buffers are
144 * restricted to 160 bits */
146 memcpy(seed, seed_in, seed_len);
148 if ((ctx = BN_CTX_new()) == NULL)
151 if ((mont = BN_MONT_CTX_new()) == NULL)
155 r0 = BN_CTX_get(ctx);
162 test = BN_CTX_get(ctx);
164 if (!BN_lshift(test, BN_value_one(), bits - 1))
168 for (;;) { /* find q */
172 if (!BN_GENCB_call(cb, 0, m++))
176 if (RAND_bytes(seed, qsize) <= 0)
181 seed_len = 0; /* use random seed if 'seed_in' turns out to
184 memcpy(buf, seed, qsize);
185 memcpy(buf2, seed, qsize);
186 /* precompute "SEED + 1" for step 7: */
187 for (i = qsize - 1; i >= 0; i--) {
194 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
196 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
198 for (i = 0; i < qsize; i++)
203 md[qsize - 1] |= 0x01;
204 if (!BN_bin2bn(md, qsize, q))
208 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
215 /* do a callback call */
219 if (!BN_GENCB_call(cb, 2, 0))
221 if (!BN_GENCB_call(cb, 3, 0))
228 n = (bits - 1) / 160;
231 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
236 /* now 'buf' contains "SEED + offset - 1" */
237 for (k = 0; k <= n; k++) {
239 * obtain "SEED + offset + k" by incrementing:
241 for (i = qsize - 1; i >= 0; i--) {
247 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
251 if (!BN_bin2bn(md, qsize, r0))
253 if (!BN_lshift(r0, r0, (qsize << 3) * k))
255 if (!BN_add(W, W, r0))
260 if (!BN_mask_bits(W, bits - 1))
264 if (!BN_add(X, X, test))
268 if (!BN_lshift1(r0, q))
270 if (!BN_mod(c, X, r0, ctx))
272 if (!BN_sub(r0, c, BN_value_one()))
274 if (!BN_sub(p, X, r0))
278 if (BN_cmp(p, test) >= 0) {
280 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
282 goto end; /* found it */
289 /* "offset = offset + n + 1" */
297 if (!BN_GENCB_call(cb, 2, 1))
300 /* We now need to generate g */
302 if (!BN_sub(test, p, BN_value_one()))
304 if (!BN_div(r0, NULL, test, q, ctx))
307 if (!BN_set_word(test, h))
309 if (!BN_MONT_CTX_set(mont, p, ctx))
314 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
318 if (!BN_add(test, test, BN_value_one()))
323 if (!BN_GENCB_call(cb, 3, 1))
335 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
339 if (counter_ret != NULL)
340 *counter_ret = counter;
344 memcpy(seed_out, seed, qsize);
349 BN_MONT_CTX_free(mont);
354 * This is a parameter generation algorithm for the DSA2 algorithm as
355 * described in FIPS 186-3.
358 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
359 const EVP_MD *evpmd, const unsigned char *seed_in,
360 size_t seed_len, int idx, unsigned char *seed_out,
361 int *counter_ret, unsigned long *h_ret,
365 unsigned char *seed = NULL, *seed_tmp = NULL;
366 unsigned char md[EVP_MAX_MD_SIZE];
368 BIGNUM *r0, *W, *X, *c, *test;
369 BIGNUM *g = NULL, *q = NULL, *p = NULL;
370 BN_MONT_CTX *mont = NULL;
371 int i, k, n = 0, m = 0, qsize = N >> 3;
378 EVP_MD_CTX_init(&mctx);
384 evpmd = EVP_sha224();
386 evpmd = EVP_sha256();
389 mdsize = M_EVP_MD_size(evpmd);
390 /* If unverificable g generation only don't need seed */
391 if (!ret->p || !ret->q || idx >= 0) {
395 seed = OPENSSL_malloc(seed_len);
400 seed_tmp = OPENSSL_malloc(seed_len);
402 if (!seed || !seed_tmp)
406 memcpy(seed, seed_in, seed_len);
410 if ((ctx = BN_CTX_new()) == NULL)
413 if ((mont = BN_MONT_CTX_new()) == NULL)
417 r0 = BN_CTX_get(ctx);
422 test = BN_CTX_get(ctx);
424 /* if p, q already supplied generate g only */
425 if (ret->p && ret->q) {
429 memcpy(seed_tmp, seed, seed_len);
436 if (!BN_lshift(test, BN_value_one(), L - 1))
439 for (;;) { /* find q */
442 if (!BN_GENCB_call(cb, 0, m++))
446 if (RAND_bytes(seed, seed_len) <= 0)
450 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
452 /* Take least significant bits of md */
454 pmd = md + mdsize - qsize;
459 memset(md + mdsize, 0, qsize - mdsize);
463 pmd[qsize - 1] |= 0x01;
464 if (!BN_bin2bn(pmd, qsize, q))
468 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
469 seed_in ? 1 : 0, cb);
474 /* Provided seed didn't produce a prime: error */
477 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
481 /* do a callback call */
484 /* Copy seed to seed_out before we mess with it */
486 memcpy(seed_out, seed, seed_len);
488 if (!BN_GENCB_call(cb, 2, 0))
490 if (!BN_GENCB_call(cb, 3, 0))
497 n = (L - 1) / (mdsize << 3);
500 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
505 /* now 'buf' contains "SEED + offset - 1" */
506 for (k = 0; k <= n; k++) {
508 * obtain "SEED + offset + k" by incrementing:
510 for (i = seed_len - 1; i >= 0; i--) {
516 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
520 if (!BN_bin2bn(md, mdsize, r0))
522 if (!BN_lshift(r0, r0, (mdsize << 3) * k))
524 if (!BN_add(W, W, r0))
529 if (!BN_mask_bits(W, L - 1))
533 if (!BN_add(X, X, test))
537 if (!BN_lshift1(r0, q))
539 if (!BN_mod(c, X, r0, ctx))
541 if (!BN_sub(r0, c, BN_value_one()))
543 if (!BN_sub(p, X, r0))
547 if (BN_cmp(p, test) >= 0) {
549 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
551 goto end; /* found it */
558 /* "offset = offset + n + 1" */
561 if (counter >= (int)(4 * L))
566 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
571 if (!BN_GENCB_call(cb, 2, 1))
576 /* We now need to generate g */
578 if (!BN_sub(test, p, BN_value_one()))
580 if (!BN_div(r0, NULL, test, q, ctx))
584 if (!BN_set_word(test, h))
588 if (!BN_MONT_CTX_set(mont, p, ctx))
592 static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
595 md[1] = (h >> 8) & 0xff;
597 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
599 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
601 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
603 if (!EVP_DigestUpdate(&mctx, md, 3))
605 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
607 if (!BN_bin2bn(md, mdsize, test))
611 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
615 if (idx < 0 && !BN_add(test, test, BN_value_one()))
618 if (idx >= 0 && h > 0xffff)
622 if (!BN_GENCB_call(cb, 3, 1))
638 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
642 if (counter_ret != NULL)
643 *counter_ret = counter;
648 if (seed_out != seed_tmp)
649 OPENSSL_free(seed_tmp);
653 BN_MONT_CTX_free(mont);
654 EVP_MD_CTX_cleanup(&mctx);
658 int dsa_paramgen_check_g(DSA *dsa)
662 BN_MONT_CTX *mont = NULL;
668 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
670 if (BN_cmp(dsa->g, dsa->p) >= 0)
672 tmp = BN_CTX_get(ctx);
675 if ((mont = BN_MONT_CTX_new()) == NULL)
677 if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
679 /* Work out g^q mod p */
680 if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
682 if (!BN_cmp(tmp, BN_value_one()))
688 BN_MONT_CTX_free(mont);