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
79 #include <openssl/evp.h>
80 #include <openssl/bn.h>
81 #include <openssl/dsa.h>
82 #include <openssl/rand.h>
83 #include <openssl/sha.h>
85 static int dsa_builtin_paramgen(DSA *ret, int bits,
86 unsigned char *seed_in, int seed_len,
87 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
89 int DSA_generate_parameters_ex(DSA *ret, int bits,
90 unsigned char *seed_in, int seed_len,
91 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
93 if(ret->meth->dsa_paramgen)
94 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len,
95 counter_ret, h_ret, cb);
96 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len,
97 counter_ret, h_ret, cb);
100 static int dsa_builtin_paramgen(DSA *ret, int bits,
101 unsigned char *seed_in, int seed_len,
102 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
105 unsigned char seed[SHA_DIGEST_LENGTH];
106 unsigned char md[SHA_DIGEST_LENGTH];
107 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
108 BIGNUM *r0,*W,*X,*c,*test;
109 BIGNUM *g=NULL,*q=NULL,*p=NULL;
110 BN_MONT_CTX *mont=NULL;
117 if (bits < 512) bits=512;
118 bits=(bits+63)/64*64;
121 seed_in = NULL; /* seed buffer too small -- ignore */
123 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
124 * but our internal buffers are restricted to 160 bits*/
125 if ((seed_in != NULL) && (seed_len == 20))
126 memcpy(seed,seed_in,seed_len);
128 if ((ctx=BN_CTX_new()) == NULL) goto err;
130 if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
133 r0 = BN_CTX_get(ctx);
140 test = BN_CTX_get(ctx);
142 if (!BN_lshift(test,BN_value_one(),bits-1))
147 for (;;) /* find q */
152 if(!BN_GENCB_call(cb, 0, m++))
157 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
163 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
165 memcpy(buf,seed,SHA_DIGEST_LENGTH);
166 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
167 /* precompute "SEED + 1" for step 7: */
168 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
171 if (buf[i] != 0) break;
175 EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
176 EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
177 for (i=0; i<SHA_DIGEST_LENGTH; i++)
182 md[SHA_DIGEST_LENGTH-1]|=0x01;
183 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
186 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
193 /* do a callback call */
197 if(!BN_GENCB_call(cb, 2, 0)) goto err;
198 if(!BN_GENCB_call(cb, 3, 0)) goto err;
209 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
214 /* now 'buf' contains "SEED + offset - 1" */
217 /* obtain "SEED + offset + k" by incrementing: */
218 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
221 if (buf[i] != 0) break;
224 EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
227 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
229 if (!BN_lshift(r0,r0,160*k)) goto err;
230 if (!BN_add(W,W,r0)) goto err;
234 if (!BN_mask_bits(W,bits-1)) goto err;
235 if (!BN_copy(X,W)) goto err;
236 if (!BN_add(X,X,test)) goto err;
239 if (!BN_lshift1(r0,q)) goto err;
240 if (!BN_mod(c,X,r0,ctx)) goto err;
241 if (!BN_sub(r0,c,BN_value_one())) goto err;
242 if (!BN_sub(p,X,r0)) goto err;
245 if (BN_cmp(p,test) >= 0)
248 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
251 goto end; /* found it */
258 /* "offset = offset + n + 1" */
261 if (counter >= 4096) break;
265 if(!BN_GENCB_call(cb, 2, 1))
268 /* We now need to generate g */
270 if (!BN_sub(test,p,BN_value_one())) goto err;
271 if (!BN_div(r0,NULL,test,q,ctx)) goto err;
273 if (!BN_set_word(test,h)) goto err;
274 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
279 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
280 if (!BN_is_one(g)) break;
281 if (!BN_add(test,test,BN_value_one())) goto err;
285 if(!BN_GENCB_call(cb, 3, 1))
292 if(ret->p) BN_free(ret->p);
293 if(ret->q) BN_free(ret->q);
294 if(ret->g) BN_free(ret->g);
298 if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
303 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
304 if (counter_ret != NULL) *counter_ret=counter;
305 if (h_ret != NULL) *h_ret=h;
312 if (mont != NULL) BN_MONT_CTX_free(mont);