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>
86 # include "dsa_locl.h"
89 /* Workaround bug in prototype */
90 # define fips_dsa_builtin_paramgen2 fips_dsa_paramgen_bad
91 # include <openssl/fips.h>
94 int DSA_generate_parameters_ex(DSA *ret, int bits,
95 const unsigned char *seed_in, int seed_len,
96 int *counter_ret, unsigned long *h_ret,
100 if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD)
101 && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) {
102 DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD);
106 if (ret->meth->dsa_paramgen)
107 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
108 counter_ret, h_ret, cb);
110 else if (FIPS_mode()) {
111 return FIPS_dsa_generate_parameters_ex(ret, bits,
113 counter_ret, h_ret, cb);
117 const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
118 size_t qbits = EVP_MD_size(evpmd) * 8;
120 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
121 seed_in, seed_len, NULL, counter_ret,
126 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
127 const EVP_MD *evpmd, const unsigned char *seed_in,
128 size_t seed_len, unsigned char *seed_out,
129 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
132 unsigned char seed[SHA256_DIGEST_LENGTH];
133 unsigned char md[SHA256_DIGEST_LENGTH];
134 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
135 BIGNUM *r0, *W, *X, *c, *test;
136 BIGNUM *g = NULL, *q = NULL, *p = NULL;
137 BN_MONT_CTX *mont = NULL;
138 int i, k, n = 0, m = 0, qsize = qbits >> 3;
144 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
145 qsize != SHA256_DIGEST_LENGTH)
150 if (qsize == SHA_DIGEST_LENGTH)
152 else if (qsize == SHA224_DIGEST_LENGTH)
153 evpmd = EVP_sha224();
155 evpmd = EVP_sha256();
157 qsize = EVP_MD_size(evpmd);
163 bits = (bits + 63) / 64 * 64;
166 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
169 if (seed_len && (seed_len < (size_t)qsize))
170 seed_in = NULL; /* seed buffer too small -- ignore */
171 if (seed_len > (size_t)qsize)
172 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger
173 * SEED, but our internal buffers are
174 * restricted to 160 bits */
176 memcpy(seed, seed_in, seed_len);
178 if ((mont = BN_MONT_CTX_new()) == NULL)
181 if ((ctx = BN_CTX_new()) == NULL)
186 r0 = BN_CTX_get(ctx);
193 test = BN_CTX_get(ctx);
198 if (!BN_lshift(test, BN_value_one(), bits - 1))
202 for (;;) { /* find q */
206 if (!BN_GENCB_call(cb, 0, m++))
209 if (!seed_len || !seed_in) {
210 if (RAND_bytes(seed, qsize) <= 0)
215 seed_len = 0; /* use random seed if 'seed_in' turns out to
218 memcpy(buf, seed, qsize);
219 memcpy(buf2, seed, qsize);
220 /* precompute "SEED + 1" for step 7: */
221 for (i = qsize - 1; i >= 0; i--) {
228 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
230 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
232 for (i = 0; i < qsize; i++)
237 md[qsize - 1] |= 0x01;
238 if (!BN_bin2bn(md, qsize, q))
242 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
249 /* do a callback call */
253 if (!BN_GENCB_call(cb, 2, 0))
255 if (!BN_GENCB_call(cb, 3, 0))
262 n = (bits - 1) / 160;
265 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
270 /* now 'buf' contains "SEED + offset - 1" */
271 for (k = 0; k <= n; k++) {
273 * obtain "SEED + offset + k" by incrementing:
275 for (i = qsize - 1; i >= 0; i--) {
281 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
285 if (!BN_bin2bn(md, qsize, r0))
287 if (!BN_lshift(r0, r0, (qsize << 3) * k))
289 if (!BN_add(W, W, r0))
294 if (!BN_mask_bits(W, bits - 1))
298 if (!BN_add(X, X, test))
302 if (!BN_lshift1(r0, q))
304 if (!BN_mod(c, X, r0, ctx))
306 if (!BN_sub(r0, c, BN_value_one()))
308 if (!BN_sub(p, X, r0))
312 if (BN_cmp(p, test) >= 0) {
314 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
316 goto end; /* found it */
323 /* "offset = offset + n + 1" */
331 if (!BN_GENCB_call(cb, 2, 1))
334 /* We now need to generate g */
336 if (!BN_sub(test, p, BN_value_one()))
338 if (!BN_div(r0, NULL, test, q, ctx))
341 if (!BN_set_word(test, h))
343 if (!BN_MONT_CTX_set(mont, p, ctx))
348 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
352 if (!BN_add(test, test, BN_value_one()))
357 if (!BN_GENCB_call(cb, 3, 1))
372 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
376 if (counter_ret != NULL)
377 *counter_ret = counter;
381 memcpy(seed_out, seed, qsize);
388 BN_MONT_CTX_free(mont);
393 # undef fips_dsa_builtin_paramgen2
394 extern int fips_dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
396 const unsigned char *seed_in,
397 size_t seed_len, int idx,
398 unsigned char *seed_out,
399 int *counter_ret, unsigned long *h_ret,
404 * This is a parameter generation algorithm for the DSA2 algorithm as
405 * described in FIPS 186-3.
408 int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
409 const EVP_MD *evpmd, const unsigned char *seed_in,
410 size_t seed_len, int idx, unsigned char *seed_out,
411 int *counter_ret, unsigned long *h_ret,
415 unsigned char *seed = NULL, *seed_tmp = NULL;
416 unsigned char md[EVP_MAX_MD_SIZE];
418 BIGNUM *r0, *W, *X, *c, *test;
419 BIGNUM *g = NULL, *q = NULL, *p = NULL;
420 BN_MONT_CTX *mont = NULL;
421 int i, k, n = 0, m = 0, qsize = N >> 3;
431 return fips_dsa_builtin_paramgen2(ret, L, N, evpmd,
432 seed_in, seed_len, idx,
433 seed_out, counter_ret, h_ret, cb);
436 EVP_MD_CTX_init(&mctx);
442 evpmd = EVP_sha224();
444 evpmd = EVP_sha256();
447 mdsize = EVP_MD_size(evpmd);
448 /* If unverificable g generation only don't need seed */
449 if (!ret->p || !ret->q || idx >= 0) {
453 seed = OPENSSL_malloc(seed_len);
458 seed_tmp = OPENSSL_malloc(seed_len);
460 if (!seed || !seed_tmp)
464 memcpy(seed, seed_in, seed_len);
468 if ((ctx = BN_CTX_new()) == NULL)
471 if ((mont = BN_MONT_CTX_new()) == NULL)
475 r0 = BN_CTX_get(ctx);
480 test = BN_CTX_get(ctx);
482 /* if p, q already supplied generate g only */
483 if (ret->p && ret->q) {
487 memcpy(seed_tmp, seed, seed_len);
496 if (!BN_lshift(test, BN_value_one(), L - 1))
499 for (;;) { /* find q */
502 if (!BN_GENCB_call(cb, 0, m++))
506 if (RAND_bytes(seed, seed_len) <= 0)
510 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
512 /* Take least significant bits of md */
514 pmd = md + mdsize - qsize;
519 memset(md + mdsize, 0, qsize - mdsize);
523 pmd[qsize - 1] |= 0x01;
524 if (!BN_bin2bn(pmd, qsize, q))
528 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
529 seed_in ? 1 : 0, cb);
534 /* Provided seed didn't produce a prime: error */
537 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
541 /* do a callback call */
544 /* Copy seed to seed_out before we mess with it */
546 memcpy(seed_out, seed, seed_len);
548 if (!BN_GENCB_call(cb, 2, 0))
550 if (!BN_GENCB_call(cb, 3, 0))
557 n = (L - 1) / (mdsize << 3);
560 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
565 /* now 'buf' contains "SEED + offset - 1" */
566 for (k = 0; k <= n; k++) {
568 * obtain "SEED + offset + k" by incrementing:
570 for (i = seed_len - 1; i >= 0; i--) {
576 if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
580 if (!BN_bin2bn(md, mdsize, r0))
582 if (!BN_lshift(r0, r0, (mdsize << 3) * k))
584 if (!BN_add(W, W, r0))
589 if (!BN_mask_bits(W, L - 1))
593 if (!BN_add(X, X, test))
597 if (!BN_lshift1(r0, q))
599 if (!BN_mod(c, X, r0, ctx))
601 if (!BN_sub(r0, c, BN_value_one()))
603 if (!BN_sub(p, X, r0))
607 if (BN_cmp(p, test) >= 0) {
609 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
611 goto end; /* found it */
618 /* "offset = offset + n + 1" */
621 if (counter >= (int)(4 * L))
626 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
631 if (!BN_GENCB_call(cb, 2, 1))
636 /* We now need to generate g */
638 if (!BN_sub(test, p, BN_value_one()))
640 if (!BN_div(r0, NULL, test, q, ctx))
644 if (!BN_set_word(test, h))
648 if (!BN_MONT_CTX_set(mont, p, ctx))
652 static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e };
655 md[1] = (h >> 8) & 0xff;
657 if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
659 if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
661 if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
663 if (!EVP_DigestUpdate(&mctx, md, 3))
665 if (!EVP_DigestFinal_ex(&mctx, md, NULL))
667 if (!BN_bin2bn(md, mdsize, test))
671 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
675 if (idx < 0 && !BN_add(test, test, BN_value_one()))
678 if (idx >= 0 && h > 0xffff)
682 if (!BN_GENCB_call(cb, 3, 1))
701 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
705 if (counter_ret != NULL)
706 *counter_ret = counter;
712 if (seed_out != seed_tmp)
713 OPENSSL_free(seed_tmp);
719 BN_MONT_CTX_free(mont);
720 EVP_MD_CTX_cleanup(&mctx);
724 int dsa_paramgen_check_g(DSA *dsa)
728 BN_MONT_CTX *mont = NULL;
734 if (BN_cmp(dsa->g, BN_value_one()) <= 0)
736 if (BN_cmp(dsa->g, dsa->p) >= 0)
738 tmp = BN_CTX_get(ctx);
741 if ((mont = BN_MONT_CTX_new()) == NULL)
743 if (!BN_MONT_CTX_set(mont, dsa->p, ctx))
745 /* Work out g^q mod p */
746 if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont))
748 if (!BN_cmp(tmp, BN_value_one()))
755 BN_MONT_CTX_free(mont);