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 # include <openssl/fips.h>
92 int DSA_generate_parameters_ex(DSA *ret, int bits,
93 const unsigned char *seed_in, int seed_len,
94 int *counter_ret, unsigned long *h_ret,
98 if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD)
99 && !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) {
100 DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD);
104 if (ret->meth->dsa_paramgen)
105 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
106 counter_ret, h_ret, cb);
108 else if (FIPS_mode()) {
109 return FIPS_dsa_generate_parameters_ex(ret, bits,
111 counter_ret, h_ret, cb);
115 const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1();
116 size_t qbits = EVP_MD_size(evpmd) * 8;
118 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
119 seed_in, seed_len, NULL, counter_ret,
124 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
125 const EVP_MD *evpmd, const unsigned char *seed_in,
126 size_t seed_len, unsigned char *seed_out,
127 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
130 unsigned char seed[SHA256_DIGEST_LENGTH];
131 unsigned char md[SHA256_DIGEST_LENGTH];
132 unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
133 BIGNUM *r0, *W, *X, *c, *test;
134 BIGNUM *g = NULL, *q = NULL, *p = NULL;
135 BN_MONT_CTX *mont = NULL;
136 int i, k, n = 0, m = 0, qsize = qbits >> 3;
142 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
143 qsize != SHA256_DIGEST_LENGTH)
148 /* use SHA1 as default */
154 bits = (bits + 63) / 64 * 64;
157 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
160 if (seed_len && (seed_len < (size_t)qsize))
161 seed_in = NULL; /* seed buffer too small -- ignore */
162 if (seed_len > (size_t)qsize)
163 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger
164 * SEED, but our internal buffers are
165 * restricted to 160 bits */
167 memcpy(seed, seed_in, seed_len);
169 if ((mont = BN_MONT_CTX_new()) == NULL)
172 if ((ctx = BN_CTX_new()) == NULL)
177 r0 = BN_CTX_get(ctx);
184 test = BN_CTX_get(ctx);
186 if (!BN_lshift(test, BN_value_one(), bits - 1))
190 for (;;) { /* find q */
194 if (!BN_GENCB_call(cb, 0, m++))
197 if (!seed_len || !seed_in) {
198 if (RAND_pseudo_bytes(seed, qsize) < 0)
203 seed_len = 0; /* use random seed if 'seed_in' turns out to
206 memcpy(buf, seed, qsize);
207 memcpy(buf2, seed, qsize);
208 /* precompute "SEED + 1" for step 7: */
209 for (i = qsize - 1; i >= 0; i--) {
216 if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
218 if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
220 for (i = 0; i < qsize; i++)
225 md[qsize - 1] |= 0x01;
226 if (!BN_bin2bn(md, qsize, q))
230 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
237 /* do a callback call */
241 if (!BN_GENCB_call(cb, 2, 0))
243 if (!BN_GENCB_call(cb, 3, 0))
250 n = (bits - 1) / 160;
253 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
258 /* now 'buf' contains "SEED + offset - 1" */
259 for (k = 0; k <= n; k++) {
261 * obtain "SEED + offset + k" by incrementing:
263 for (i = qsize - 1; i >= 0; i--) {
269 if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL))
273 if (!BN_bin2bn(md, qsize, r0))
275 if (!BN_lshift(r0, r0, (qsize << 3) * k))
277 if (!BN_add(W, W, r0))
282 if (!BN_mask_bits(W, bits - 1))
286 if (!BN_add(X, X, test))
290 if (!BN_lshift1(r0, q))
292 if (!BN_mod(c, X, r0, ctx))
294 if (!BN_sub(r0, c, BN_value_one()))
296 if (!BN_sub(p, X, r0))
300 if (BN_cmp(p, test) >= 0) {
302 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
304 goto end; /* found it */
311 /* "offset = offset + n + 1" */
319 if (!BN_GENCB_call(cb, 2, 1))
322 /* We now need to generate g */
324 if (!BN_sub(test, p, BN_value_one()))
326 if (!BN_div(r0, NULL, test, q, ctx))
329 if (!BN_set_word(test, h))
331 if (!BN_MONT_CTX_set(mont, p, ctx))
336 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
340 if (!BN_add(test, test, BN_value_one()))
345 if (!BN_GENCB_call(cb, 3, 1))
360 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
364 if (counter_ret != NULL)
365 *counter_ret = counter;
369 memcpy(seed_out, seed, qsize);
376 BN_MONT_CTX_free(mont);