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.]
75 DSA *DSA_generate_parameters(bits,seed_in,seed_len,counter_ret,h_ret,callback,
78 unsigned char *seed_in;
86 unsigned char seed[SHA_DIGEST_LENGTH];
87 unsigned char md[SHA_DIGEST_LENGTH];
88 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
89 BIGNUM *r0,*W,*X,*c,*test;
90 BIGNUM *g=NULL,*q=NULL,*p=NULL;
93 BN_CTX *ctx=NULL,*ctx2=NULL;
97 if (bits < 512) bits=512;
100 if ((seed_in != NULL) && (seed_len == 20))
101 memcpy(seed,seed_in,seed_len);
104 if (ctx == NULL) goto err;
106 if (ctx2 == NULL) goto err;
108 if (ret == NULL) goto err;
118 BN_lshift(test,BN_value_one(),bits-1);
125 if (callback != NULL) callback(0,m++,cb_arg);
128 RAND_bytes(seed,SHA_DIGEST_LENGTH);
132 memcpy(buf,seed,SHA_DIGEST_LENGTH);
133 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
134 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
137 if (buf[i] != 0) break;
141 HASH(seed,SHA_DIGEST_LENGTH,md);
142 HASH(buf,SHA_DIGEST_LENGTH,buf2);
143 for (i=0; i<SHA_DIGEST_LENGTH; i++)
148 md[SHA_DIGEST_LENGTH-1]|=0x01;
149 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort();
152 if (DSA_is_prime(q,callback,cb_arg) > 0) break;
153 /* do a callback call */
157 if (callback != NULL) callback(2,0,cb_arg);
158 if (callback != NULL) callback(3,0,cb_arg);
172 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
175 if (buf[i] != 0) break;
178 HASH(buf,SHA_DIGEST_LENGTH,md);
181 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
182 BN_lshift(r0,r0,160*k);
187 BN_mask_bits(W,bits-1);
188 BN_copy(X,W); /* this should be ok */
189 BN_add(X,X,test); /* this should be ok */
194 BN_sub(r0,c,BN_value_one());
198 if (BN_cmp(p,test) >= 0)
201 if (DSA_is_prime(p,callback,cb_arg) > 0)
209 if (counter >= 4096) break;
211 if (callback != NULL) callback(0,counter,cb_arg);
215 if (callback != NULL) callback(2,1,cb_arg);
217 /* We now need to gernerate g */
219 BN_sub(test,p,BN_value_one());
220 BN_div(r0,NULL,test,q,ctx);
226 BN_mod_exp(g,test,r0,p,ctx);
227 if (!BN_is_one(g)) break;
228 BN_add(test,test,BN_value_one());
232 if (callback != NULL) callback(3,1,cb_arg);
238 if (ret != NULL) DSA_free(ret);
245 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
246 if (counter_ret != NULL) *counter_ret=counter;
247 if (h_ret != NULL) *h_ret=h;
254 int DSA_is_prime(w, callback,cb_arg)
260 BN_CTX *ctx=NULL,*ctx2=NULL;
261 BIGNUM *w_1,*b,*m,*z;
264 if (!BN_is_bit_set(w,0)) return(0);
267 if (ctx == NULL) goto err;
269 if (ctx2 == NULL) goto err;
280 if (!BN_sub(w_1,w,BN_value_one())) goto err;
281 for (a=1; !BN_is_bit_set(w_1,a); a++)
283 if (!BN_rshift(m,w_1,a)) goto err;
285 for (i=1; i < n; i++)
288 BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0);
289 BN_set_word(b,0x10001L);
293 if (!BN_mod_exp(z,b,m,w,ctx)) goto err;
298 if (((j == 0) && BN_is_one(z)) || (BN_cmp(z,w_1) == 0))
302 if ((j > 0) && BN_is_one(z))
315 if (!BN_mod_mul(z,z,z,w,ctx)) goto err;
316 if (callback != NULL) callback(1,j,cb_arg);
322 if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);