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
82 # include "cryptlib.h"
83 # include <openssl/evp.h>
84 # include <openssl/bn.h>
85 # include <openssl/dsa.h>
86 # include <openssl/rand.h>
87 # include <openssl/sha.h>
91 static int dsa_builtin_paramgen(DSA *ret, int bits,
92 unsigned char *seed_in, int seed_len,
93 int *counter_ret, unsigned long *h_ret,
96 int DSA_generate_parameters_ex(DSA *ret, int bits,
97 unsigned char *seed_in, int seed_len,
98 int *counter_ret, unsigned long *h_ret,
101 if (ret->meth->dsa_paramgen)
102 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
103 counter_ret, h_ret, cb);
104 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
105 counter_ret, h_ret, cb);
108 static int dsa_builtin_paramgen(DSA *ret, int bits,
109 unsigned char *seed_in, int seed_len,
110 int *counter_ret, unsigned long *h_ret,
114 unsigned char seed[SHA_DIGEST_LENGTH];
115 unsigned char md[SHA_DIGEST_LENGTH];
116 unsigned char buf[SHA_DIGEST_LENGTH], buf2[SHA_DIGEST_LENGTH];
117 BIGNUM *r0, *W, *X, *c, *test;
118 BIGNUM *g = NULL, *q = NULL, *p = NULL;
119 BN_MONT_CTX *mont = NULL;
120 int k, n = 0, i, m = 0;
128 bits = (bits + 63) / 64 * 64;
131 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
134 if (seed_len && (seed_len < 20))
135 seed_in = NULL; /* seed buffer too small -- ignore */
137 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger
138 * SEED, but our internal buffers are
139 * restricted to 160 bits */
140 if ((seed_in != NULL) && (seed_len == 20)) {
141 memcpy(seed, seed_in, seed_len);
142 /* set seed_in to NULL to avoid it being copied back */
146 if ((ctx = BN_CTX_new()) == NULL)
149 if ((mont = BN_MONT_CTX_new()) == NULL)
153 r0 = BN_CTX_get(ctx);
160 test = BN_CTX_get(ctx);
162 if (!BN_lshift(test, BN_value_one(), bits - 1))
166 for (;;) { /* find q */
170 if (!BN_GENCB_call(cb, 0, m++))
174 RAND_pseudo_bytes(seed, SHA_DIGEST_LENGTH);
178 seed_len = 0; /* use random seed if 'seed_in' turns out to
181 memcpy(buf, seed, SHA_DIGEST_LENGTH);
182 memcpy(buf2, seed, SHA_DIGEST_LENGTH);
183 /* precompute "SEED + 1" for step 7: */
184 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) {
191 EVP_Digest(seed, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
192 EVP_Digest(buf, SHA_DIGEST_LENGTH, buf2, NULL, HASH, NULL);
193 for (i = 0; i < SHA_DIGEST_LENGTH; i++)
198 md[SHA_DIGEST_LENGTH - 1] |= 0x01;
199 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, q))
203 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
210 /* do a callback call */
214 if (!BN_GENCB_call(cb, 2, 0))
216 if (!BN_GENCB_call(cb, 3, 0))
223 n = (bits - 1) / 160;
226 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
231 /* now 'buf' contains "SEED + offset - 1" */
232 for (k = 0; k <= n; k++) {
234 * obtain "SEED + offset + k" by incrementing:
236 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) {
242 EVP_Digest(buf, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
245 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, r0))
247 if (!BN_lshift(r0, r0, 160 * k))
249 if (!BN_add(W, W, r0))
254 if (!BN_mask_bits(W, bits - 1))
258 if (!BN_add(X, X, test))
262 if (!BN_lshift1(r0, q))
264 if (!BN_mod(c, X, r0, ctx))
266 if (!BN_sub(r0, c, BN_value_one()))
268 if (!BN_sub(p, X, r0))
272 if (BN_cmp(p, test) >= 0) {
274 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
276 goto end; /* found it */
283 /* "offset = offset + n + 1" */
291 if (!BN_GENCB_call(cb, 2, 1))
294 /* We now need to generate g */
296 if (!BN_sub(test, p, BN_value_one()))
298 if (!BN_div(r0, NULL, test, q, ctx))
301 if (!BN_set_word(test, h))
303 if (!BN_MONT_CTX_set(mont, p, ctx))
308 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
312 if (!BN_add(test, test, BN_value_one()))
317 if (!BN_GENCB_call(cb, 3, 1))
332 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
337 memcpy(seed_in, seed, 20);
338 if (counter_ret != NULL)
339 *counter_ret = counter;
348 BN_MONT_CTX_free(mont);