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.]
62 /* Parameter generation follows the original release of FIPS PUB 186,
63 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */
64 #define HASH EVP_sha()
66 /* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186,
67 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in
69 #define HASH EVP_sha1()
72 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */
74 #ifndef OPENSSL_NO_SHA
78 #include <openssl/evp.h>
79 #include <openssl/bn.h>
80 #include <openssl/rand.h>
81 #include <openssl/sha.h>
84 int DSA_generate_parameters_ex(DSA *ret, int bits,
85 const unsigned char *seed_in, int seed_len,
86 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
88 if(ret->meth->dsa_paramgen)
89 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
90 counter_ret, h_ret, cb);
94 size_t qbits = bits >= 2048 ? 256 : 160;
107 return dsa_builtin_paramgen(ret, bits, qbits, evpmd,
108 seed_in, seed_len, counter_ret, h_ret, cb);
112 int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
113 const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
114 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
117 unsigned char seed[SHA256_DIGEST_LENGTH];
118 unsigned char md[SHA256_DIGEST_LENGTH];
119 unsigned char buf[SHA256_DIGEST_LENGTH],buf2[SHA256_DIGEST_LENGTH];
120 BIGNUM *r0,*W,*X,*c,*test;
121 BIGNUM *g=NULL,*q=NULL,*p=NULL;
122 BN_MONT_CTX *mont=NULL;
123 int i, k,n=0,b,m=0, qsize = qbits >> 3;
129 if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
130 qsize != SHA256_DIGEST_LENGTH)
135 /* use SHA1 as default */
141 bits = (bits+63)/64*64;
143 /* NB: seed_len == 0 is special case: copy generated seed to
144 * seed_in if it is not NULL.
146 if (seed_len && (seed_len < (size_t)qsize))
147 seed_in = NULL; /* seed buffer too small -- ignore */
148 if (seed_len > (size_t)qsize)
149 seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
150 * but our internal buffers are restricted to 160 bits*/
152 memcpy(seed, seed_in, seed_len);
154 if ((ctx=BN_CTX_new()) == NULL)
157 if ((mont=BN_MONT_CTX_new()) == NULL)
161 r0 = BN_CTX_get(ctx);
168 test = BN_CTX_get(ctx);
170 if (!BN_lshift(test,BN_value_one(),bits-1))
175 for (;;) /* find q */
180 if(!BN_GENCB_call(cb, 0, m++))
185 RAND_pseudo_bytes(seed, qsize);
191 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
193 memcpy(buf , seed, qsize);
194 memcpy(buf2, seed, qsize);
195 /* precompute "SEED + 1" for step 7: */
196 for (i = qsize-1; i >= 0; i--)
204 EVP_Digest(seed, qsize, md, NULL, evpmd, NULL);
205 EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL);
206 for (i = 0; i < qsize; i++)
212 if (!BN_bin2bn(md, qsize, q))
216 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
223 /* do a callback call */
227 if(!BN_GENCB_call(cb, 2, 0)) goto err;
228 if(!BN_GENCB_call(cb, 3, 0)) goto err;
239 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
244 /* now 'buf' contains "SEED + offset - 1" */
247 /* obtain "SEED + offset + k" by incrementing: */
248 for (i = qsize-1; i >= 0; i--)
255 EVP_Digest(buf, qsize, md ,NULL, evpmd, NULL);
258 if (!BN_bin2bn(md, qsize, r0))
260 if (!BN_lshift(r0,r0,(qsize << 3)*k)) goto err;
261 if (!BN_add(W,W,r0)) goto err;
265 if (!BN_mask_bits(W,bits-1)) goto err;
266 if (!BN_copy(X,W)) goto err;
267 if (!BN_add(X,X,test)) goto err;
270 if (!BN_lshift1(r0,q)) goto err;
271 if (!BN_mod(c,X,r0,ctx)) goto err;
272 if (!BN_sub(r0,c,BN_value_one())) goto err;
273 if (!BN_sub(p,X,r0)) goto err;
276 if (BN_cmp(p,test) >= 0)
279 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
282 goto end; /* found it */
289 /* "offset = offset + n + 1" */
292 if (counter >= 4096) break;
296 if(!BN_GENCB_call(cb, 2, 1))
299 /* We now need to generate g */
301 if (!BN_sub(test,p,BN_value_one())) goto err;
302 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
304 if (!BN_set_word(test,h)) goto err;
305 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
310 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
311 if (!BN_is_one(g)) break;
312 if (!BN_add(test,test,BN_value_one())) goto err;
316 if(!BN_GENCB_call(cb, 3, 1))
323 if(ret->p) BN_free(ret->p);
324 if(ret->q) BN_free(ret->q);
325 if(ret->g) BN_free(ret->g);
329 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
334 if (counter_ret != NULL) *counter_ret=counter;
335 if (h_ret != NULL) *h_ret=h;
342 if (mont != NULL) BN_MONT_CTX_free(mont);