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
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>
88 # include <openssl/err.h>
92 static int dsa_builtin_paramgen(DSA *ret, int bits,
93 unsigned char *seed_in, int seed_len,
94 int *counter_ret, unsigned long *h_ret,
97 int DSA_generate_parameters_ex(DSA *ret, int bits,
98 unsigned char *seed_in, int seed_len,
99 int *counter_ret, unsigned long *h_ret,
102 if (ret->meth->dsa_paramgen)
103 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
104 counter_ret, h_ret, cb);
105 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
106 counter_ret, h_ret, cb);
109 static int dsa_builtin_paramgen(DSA *ret, int bits,
110 unsigned char *seed_in, int seed_len,
111 int *counter_ret, unsigned long *h_ret,
115 unsigned char seed[SHA_DIGEST_LENGTH];
116 unsigned char md[SHA_DIGEST_LENGTH];
117 unsigned char buf[SHA_DIGEST_LENGTH], buf2[SHA_DIGEST_LENGTH];
118 BIGNUM *r0, *W, *X, *c, *test;
119 BIGNUM *g = NULL, *q = NULL, *p = NULL;
120 BN_MONT_CTX *mont = NULL;
121 int k, n = 0, i, b, m = 0;
127 if (FIPS_selftest_failed()) {
128 FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN, FIPS_R_FIPS_SELFTEST_FAILED);
132 if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS)) {
133 DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
139 bits = (bits + 63) / 64 * 64;
142 * NB: seed_len == 0 is special case: copy generated seed to seed_in if
145 if (seed_len && (seed_len < 20))
146 seed_in = NULL; /* seed buffer too small -- ignore */
148 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger
149 * SEED, but our internal buffers are
150 * restricted to 160 bits */
151 if ((seed_in != NULL) && (seed_len == 20)) {
152 memcpy(seed, seed_in, seed_len);
153 /* set seed_in to NULL to avoid it being copied back */
157 if ((ctx = BN_CTX_new()) == NULL)
160 if ((mont = BN_MONT_CTX_new()) == NULL)
164 r0 = BN_CTX_get(ctx);
171 test = BN_CTX_get(ctx);
173 if (!BN_lshift(test, BN_value_one(), bits - 1))
177 for (;;) { /* find q */
181 if (!BN_GENCB_call(cb, 0, m++))
185 RAND_pseudo_bytes(seed, SHA_DIGEST_LENGTH);
189 seed_len = 0; /* use random seed if 'seed_in' turns out to
192 memcpy(buf, seed, SHA_DIGEST_LENGTH);
193 memcpy(buf2, seed, SHA_DIGEST_LENGTH);
194 /* precompute "SEED + 1" for step 7: */
195 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) {
202 EVP_Digest(seed, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
203 EVP_Digest(buf, SHA_DIGEST_LENGTH, buf2, NULL, HASH, NULL);
204 for (i = 0; i < SHA_DIGEST_LENGTH; i++)
209 md[SHA_DIGEST_LENGTH - 1] |= 0x01;
210 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, q))
214 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
221 /* do a callback call */
225 if (!BN_GENCB_call(cb, 2, 0))
227 if (!BN_GENCB_call(cb, 3, 0))
234 n = (bits - 1) / 160;
235 b = (bits - 1) - n * 160;
238 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
243 /* now 'buf' contains "SEED + offset - 1" */
244 for (k = 0; k <= n; k++) {
246 * obtain "SEED + offset + k" by incrementing:
248 for (i = SHA_DIGEST_LENGTH - 1; i >= 0; i--) {
254 EVP_Digest(buf, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
257 if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, r0))
259 if (!BN_lshift(r0, r0, 160 * k))
261 if (!BN_add(W, W, r0))
266 if (!BN_mask_bits(W, bits - 1))
270 if (!BN_add(X, X, test))
274 if (!BN_lshift1(r0, q))
276 if (!BN_mod(c, X, r0, ctx))
278 if (!BN_sub(r0, c, BN_value_one()))
280 if (!BN_sub(p, X, r0))
284 if (BN_cmp(p, test) >= 0) {
286 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
288 goto end; /* found it */
295 /* "offset = offset + n + 1" */
303 if (!BN_GENCB_call(cb, 2, 1))
306 /* We now need to generate g */
308 if (!BN_sub(test, p, BN_value_one()))
310 if (!BN_div(r0, NULL, test, q, ctx))
313 if (!BN_set_word(test, h))
315 if (!BN_MONT_CTX_set(mont, p, ctx))
320 if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
324 if (!BN_add(test, test, BN_value_one()))
329 if (!BN_GENCB_call(cb, 3, 1))
344 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
349 memcpy(seed_in, seed, 20);
350 if (counter_ret != NULL)
351 *counter_ret = counter;
360 BN_MONT_CTX_free(mont);