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, void (*callback)(),
87 unsigned char seed[SHA_DIGEST_LENGTH];
88 unsigned char md[SHA_DIGEST_LENGTH];
89 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
90 BIGNUM *r0,*W,*X,*c,*test;
91 BIGNUM *g=NULL,*q=NULL,*p=NULL;
92 BN_MONT_CTX *mont=NULL;
96 BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL,*ctx4=NULL;
100 if (bits < 512) bits=512;
101 bits=(bits+63)/64*64;
104 seed_in = NULL; /* seed buffer too small -- ignore */
106 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
107 * but our internal buffers are restricted to 160 bits*/
108 if ((seed_in != NULL) && (seed_len == 20))
109 memcpy(seed,seed_in,seed_len);
111 if ((ctx=BN_CTX_new()) == NULL) goto err;
112 if ((ctx2=BN_CTX_new()) == NULL) goto err;
113 if ((ctx3=BN_CTX_new()) == NULL) goto err;
114 if ((ctx4=BN_CTX_new()) == NULL) goto err;
115 if ((ret=DSA_new()) == NULL) goto err;
117 if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
126 test= &(ctx2->bn[7]);
128 BN_lshift(test,BN_value_one(),bits-1);
132 for (;;) /* find q */
137 if (callback != NULL) callback(0,m++,cb_arg);
141 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
147 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
149 memcpy(buf,seed,SHA_DIGEST_LENGTH);
150 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
151 /* precompute "SEED + 1" for step 7: */
152 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
155 if (buf[i] != 0) break;
159 HASH(seed,SHA_DIGEST_LENGTH,md);
160 HASH(buf,SHA_DIGEST_LENGTH,buf2);
161 for (i=0; i<SHA_DIGEST_LENGTH; i++)
166 md[SHA_DIGEST_LENGTH-1]|=0x01;
167 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
170 r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, ctx4, cb_arg, seed_is_random);
176 /* do a callback call */
180 if (callback != NULL) callback(2,0,cb_arg);
181 if (callback != NULL) callback(3,0,cb_arg);
192 if (callback != NULL && counter != 0)
193 callback(0,counter,cb_arg);
197 /* now 'buf' contains "SEED + offset - 1" */
200 /* obtain "SEED + offset + k" by incrementing: */
201 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
204 if (buf[i] != 0) break;
207 HASH(buf,SHA_DIGEST_LENGTH,md);
210 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
212 BN_lshift(r0,r0,160*k);
217 BN_mask_bits(W,bits-1);
218 BN_copy(X,W); /* this should be ok */
219 BN_add(X,X,test); /* this should be ok */
224 BN_sub(r0,c,BN_value_one());
228 if (BN_cmp(p,test) >= 0)
231 r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, ctx4, cb_arg, 1);
233 goto end; /* found it */
240 /* "offset = offset + n + 1" */
243 if (counter >= 4096) break;
247 if (callback != NULL) callback(2,1,cb_arg);
249 /* We now need to generate g */
251 BN_sub(test,p,BN_value_one());
252 BN_div(r0,NULL,test,q,ctx);
255 BN_MONT_CTX_set(mont,p,ctx);
260 BN_mod_exp_mont(g,test,r0,p,ctx,mont);
261 if (!BN_is_one(g)) break;
262 BN_add(test,test,BN_value_one());
266 if (callback != NULL) callback(3,1,cb_arg);
272 if (ret != NULL) DSA_free(ret);
279 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
280 if (counter_ret != NULL) *counter_ret=counter;
281 if (h_ret != NULL) *h_ret=h;
283 if (ctx != NULL) BN_CTX_free(ctx);
284 if (ctx2 != NULL) BN_CTX_free(ctx2);
285 if (ctx3 != NULL) BN_CTX_free(ctx3);
286 if (ctx4 != NULL) BN_CTX_free(ctx4);
287 if (mont != NULL) BN_MONT_CTX_free(mont);