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) */
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
77 #include <openssl/sha.h>
78 #include <openssl/bn.h>
79 #include <openssl/dsa.h>
80 #include <openssl/rand.h>
82 DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len,
83 int *counter_ret, unsigned long *h_ret,
84 void (*callback)(int, int, void *),
88 unsigned char seed[SHA_DIGEST_LENGTH];
89 unsigned char md[SHA_DIGEST_LENGTH];
90 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
91 BIGNUM *r0,*W,*X,*c,*test;
92 BIGNUM *g=NULL,*q=NULL,*p=NULL;
93 BN_MONT_CTX *mont=NULL;
97 BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL;
101 if (bits < 512) bits=512;
102 bits=(bits+63)/64*64;
105 seed_in = NULL; /* seed buffer too small -- ignore */
107 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
108 * but our internal buffers are restricted to 160 bits*/
109 if ((seed_in != NULL) && (seed_len == 20))
110 memcpy(seed,seed_in,seed_len);
112 if ((ctx=BN_CTX_new()) == NULL) goto err;
113 if ((ctx2=BN_CTX_new()) == NULL) goto err;
114 if ((ctx3=BN_CTX_new()) == NULL) goto err;
115 if ((ret=DSA_new()) == NULL) goto err;
117 if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
120 r0 = BN_CTX_get(ctx2);
121 g = BN_CTX_get(ctx2);
122 W = BN_CTX_get(ctx2);
123 q = BN_CTX_get(ctx2);
124 X = BN_CTX_get(ctx2);
125 c = BN_CTX_get(ctx2);
126 p = BN_CTX_get(ctx2);
127 test = BN_CTX_get(ctx2);
129 BN_lshift(test,BN_value_one(),bits-1);
133 for (;;) /* find q */
138 if (callback != NULL) callback(0,m++,cb_arg);
142 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
148 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
150 memcpy(buf,seed,SHA_DIGEST_LENGTH);
151 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
152 /* precompute "SEED + 1" for step 7: */
153 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
156 if (buf[i] != 0) break;
160 HASH(seed,SHA_DIGEST_LENGTH,md);
161 HASH(buf,SHA_DIGEST_LENGTH,buf2);
162 for (i=0; i<SHA_DIGEST_LENGTH; i++)
167 md[SHA_DIGEST_LENGTH-1]|=0x01;
168 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
171 r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, cb_arg, seed_is_random);
177 /* do a callback call */
181 if (callback != NULL) callback(2,0,cb_arg);
182 if (callback != NULL) callback(3,0,cb_arg);
193 if (callback != NULL && counter != 0)
194 callback(0,counter,cb_arg);
198 /* now 'buf' contains "SEED + offset - 1" */
201 /* obtain "SEED + offset + k" by incrementing: */
202 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
205 if (buf[i] != 0) break;
208 HASH(buf,SHA_DIGEST_LENGTH,md);
211 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
213 BN_lshift(r0,r0,160*k);
218 BN_mask_bits(W,bits-1);
219 BN_copy(X,W); /* this should be ok */
220 BN_add(X,X,test); /* this should be ok */
225 BN_sub(r0,c,BN_value_one());
229 if (BN_cmp(p,test) >= 0)
232 r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, cb_arg, 1);
234 goto end; /* found it */
241 /* "offset = offset + n + 1" */
244 if (counter >= 4096) break;
248 if (callback != NULL) callback(2,1,cb_arg);
250 /* We now need to generate g */
252 BN_sub(test,p,BN_value_one());
253 BN_div(r0,NULL,test,q,ctx);
256 BN_MONT_CTX_set(mont,p,ctx);
261 BN_mod_exp_mont(g,test,r0,p,ctx,mont);
262 if (!BN_is_one(g)) break;
263 BN_add(test,test,BN_value_one());
267 if (callback != NULL) callback(3,1,cb_arg);
273 if (ret != NULL) DSA_free(ret);
280 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
281 if (counter_ret != NULL) *counter_ret=counter;
282 if (h_ret != NULL) *h_ret=h;
284 if (ctx != NULL) BN_CTX_free(ctx);
290 if (ctx3 != NULL) BN_CTX_free(ctx3);
291 if (mont != NULL) BN_MONT_CTX_free(mont);