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.]
63 * Parameter generation follows the original release of FIPS PUB 186,
64 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180)
66 # define HASH EVP_sha()
69 * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
70 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB
73 # define HASH EVP_sha1()
76 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
78 #ifndef OPENSSL_NO_SHA
81 # include "cryptlib.h"
82 # include <openssl/evp.h>
83 # include <openssl/bn.h>
84 # include <openssl/rand.h>
85 # include <openssl/sha.h>
87 # include "dsa_locl.h"
89 int DSA_generate_parameters_ex(DSA *ret, int bits,
90 const unsigned char *seed_in, int seed_len,
91 int *counter_ret, unsigned long *h_ret,
94 if (ret->meth->dsa_paramgen)
95 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
96 counter_ret, h_ret, cb);
99 size_t qbits = bits >= 2048 ? 256 : 160;
103 evpmd = EVP_sha256();
109 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
110 seed_in, seed_len, NULL, counter_ret,
115 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
116 const EVP_MD *evpmd, const unsigned char *seed_in,
117 size_t seed_len, unsigned char *seed_out,
118 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
121 unsigned char seed[SHA256_DIGEST_LENGTH];
122 unsigned char md[SHA256_DIGEST_LENGTH];
123 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
124 BIGNUM *r0, *W, *X, *c, *test;
125 BIGNUM *g = NULL, *q = NULL, *p = NULL;
126 BN_MONT_CTX *mont = NULL;
127 int i, k, n = 0, m = 0, qsize = qbits >> 3;
133 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
134 qsize != SHA256_DIGEST_LENGTH)
139 /* use SHA1 as default */
145 bits = (bits + 63) / 64 * 64;
148 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
151 if (seed_len && (seed_len < (size_t)qsize))
152 seed_in = NULL; /* seed buffer too small -- ignore */
153 if (seed_len > (size_t)qsize)
154 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger
155 * SEED, but our internal buffers are
156 * restricted to 160 bits */
158 memcpy(seed, seed_in, seed_len);
160 if ((ctx = BN_CTX_new()) == NULL)
163 if ((mont = BN_MONT_CTX_new()) == NULL)
167 r0 = BN_CTX_get(ctx);
174 test = BN_CTX_get(ctx);
176 if (!BN_lshift(test, BN_value_one(), bits - 1))
180 for (;;) { /* find q */
184 if (!BN_GENCB_call(cb, 0, m++))
188 if (RAND_pseudo_bytes(seed, qsize) < 0)
193 seed_len = 0; /* use random seed if 'seed_in' turns out to
196 memcpy(buf, seed, qsize);
197 memcpy(buf2, seed, qsize);
198 /* precompute "SEED + 1" for step 7: */
199 for (i = qsize - 1; i >= 0; i--) {
206 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
208 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
210 for (i = 0; i < qsize; i++)
215 md[qsize - 1] |= 0x01;
216 if (!BN_bin2bn(md, qsize, q))
220 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
227 /* do a callback call */
231 if (!BN_GENCB_call(cb, 2, 0))
233 if (!BN_GENCB_call(cb, 3, 0))
240 n = (bits - 1) / 160;
243 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
248 /* now 'buf' contains "SEED + offset - 1" */
249 for (k = 0; k <= n; k++) {
251 * obtain "SEED + offset + k" by incrementing:
253 for (i = qsize - 1; i >= 0; i--) {
259 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
263 if (!BN_bin2bn(md, qsize, r0))
265 if (!BN_lshift(r0, r0, (qsize << 3) * k))
267 if (!BN_add(W, W, r0))
272 if (!BN_mask_bits(W, bits - 1))
276 if (!BN_add(X, X, test))
280 if (!BN_lshift1(r0, q))
282 if (!BN_mod(c, X, r0, ctx))
284 if (!BN_sub(r0, c, BN_value_one()))
286 if (!BN_sub(p, X, r0))
290 if (BN_cmp(p, test) >= 0) {
292 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
294 goto end; /* found it */
301 /* "offset = offset + n + 1" */
309 if (!BN_GENCB_call(cb, 2, 1))
312 /* We now need to generate g */
314 if (!BN_sub(test, p, BN_value_one()))
316 if (!BN_div(r0, NULL, test, q, ctx))
319 if (!BN_set_word(test, h))
321 if (!BN_MONT_CTX_set(mont, p, ctx))
326 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
330 if (!BN_add(test, test, BN_value_one()))
335 if (!BN_GENCB_call(cb, 3, 1))
350 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
354 if (counter_ret != NULL)
355 *counter_ret = counter;
359 memcpy(seed_out, seed, qsize);
366 BN_MONT_CTX_free(mont);
371 * This is a parameter generation algorithm for the DSA2 algorithm as
372 * described in FIPS 186-3.
375 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
376 const EVP_MD *evpmd, const unsigned char *seed_in,
377 size_t seed_len, int idx, unsigned char *seed_out,
378 int *counter_ret, unsigned long *h_ret,
382 unsigned char *seed = NULL, *seed_tmp = NULL;
383 unsigned char md[EVP_MAX_MD_SIZE];
385 BIGNUM *r0, *W, *X, *c, *test;
386 BIGNUM *g = NULL, *q = NULL, *p = NULL;
387 BN_MONT_CTX *mont = NULL;
388 int i, k, n = 0, m = 0, qsize = N >> 3;
395 EVP_MD_CTX_init(&mctx);
401 evpmd = EVP_sha224();
403 evpmd = EVP_sha256();
406 mdsize = M_EVP_MD_size(evpmd);
407 /* If unverificable g generation only don't need seed */
408 if (!ret->p || !ret->q || idx >= 0) {
412 seed = OPENSSL_malloc(seed_len);
417 seed_tmp = OPENSSL_malloc(seed_len);
419 if (!seed || !seed_tmp)
423 memcpy(seed, seed_in, seed_len);
427 if ((ctx = BN_CTX_new()) == NULL)
430 if ((mont = BN_MONT_CTX_new()) == NULL)
434 r0 = BN_CTX_get(ctx);
439 test = BN_CTX_get(ctx);
441 /* if p, q already supplied generate g only */
442 if (ret->p && ret->q) {
446 memcpy(seed_tmp, seed, seed_len);
453 if (!BN_lshift(test, BN_value_one(), L - 1))
456 for (;;) { /* find q */
459 if (!BN_GENCB_call(cb, 0, m++))
463 if (RAND_pseudo_bytes(seed, seed_len) < 0)
467 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
469 /* Take least significant bits of md */
471 pmd = md + mdsize - qsize;
476 memset(md + mdsize, 0, qsize - mdsize);
480 pmd[qsize - 1] |= 0x01;
481 if (!BN_bin2bn(pmd, qsize, q))
485 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
486 seed_in ? 1 : 0, cb);
491 /* Provided seed didn't produce a prime: error */
494 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
498 /* do a callback call */
501 /* Copy seed to seed_out before we mess with it */
503 memcpy(seed_out, seed, seed_len);
505 if (!BN_GENCB_call(cb, 2, 0))
507 if (!BN_GENCB_call(cb, 3, 0))
514 n = (L - 1) / (mdsize << 3);
517 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
522 /* now 'buf' contains "SEED + offset - 1" */
523 for (k = 0; k <= n; k++) {
525 * obtain "SEED + offset + k" by incrementing:
527 for (i = seed_len - 1; i >= 0; i--) {
533 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
537 if (!BN_bin2bn(md, mdsize, r0))
539 if (!BN_lshift(r0, r0, (mdsize << 3) * k))
541 if (!BN_add(W, W, r0))
546 if (!BN_mask_bits(W, L - 1))
550 if (!BN_add(X, X, test))
554 if (!BN_lshift1(r0, q))
556 if (!BN_mod(c, X, r0, ctx))
558 if (!BN_sub(r0, c, BN_value_one()))
560 if (!BN_sub(p, X, r0))
564 if (BN_cmp(p, test) >= 0) {
566 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
568 goto end; /* found it */
575 /* "offset = offset + n + 1" */
578 if (counter >= (int)(4 * L))
583 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
588 if (!BN_GENCB_call(cb, 2, 1))
593 /* We now need to generate g */
595 if (!BN_sub(test, p, BN_value_one()))
597 if (!BN_div(r0, NULL, test, q, ctx))
601 if (!BN_set_word(test, h))
605 if (!BN_MONT_CTX_set(mont, p, ctx))
609 static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
612 md[1] = (h >> 8) & 0xff;
614 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
616 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
618 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
620 if (!EVP_DigestUpdate(&mctx, md, 3))
622 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
624 if (!BN_bin2bn(md, mdsize, test))
628 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
632 if (idx < 0 && !BN_add(test, test, BN_value_one()))
635 if (idx >= 0 && h > 0xffff)
639 if (!BN_GENCB_call(cb, 3, 1))
658 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
662 if (counter_ret != NULL)
663 *counter_ret = counter;
669 if (seed_out != seed_tmp)
670 OPENSSL_free(seed_tmp);
676 BN_MONT_CTX_free(mont);
677 EVP_MD_CTX_cleanup(&mctx);
681 int dsa_paramgen_check_g(DSA *dsa)
685 BN_MONT_CTX *mont = NULL;
691 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
693 if (BN_cmp(dsa->g, dsa->p) >= 0)
695 tmp = BN_CTX_get(ctx);
698 if ((mont = BN_MONT_CTX_new()) == NULL)
700 if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
702 /* Work out g^q mod p */
703 if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
705 if (!BN_cmp(tmp, BN_value_one()))
712 BN_MONT_CTX_free(mont);