1 /* crypto/dsa/dsa_gen.c */
2 /* Copyright (C) 1995-1997 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)
77 unsigned char *seed_in;
84 unsigned char seed[SHA_DIGEST_LENGTH];
85 unsigned char md[SHA_DIGEST_LENGTH];
86 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
87 BIGNUM *r0,*W,*X,*c,*test;
88 BIGNUM *g=NULL,*q=NULL,*p=NULL;
91 BN_CTX *ctx=NULL,*ctx2=NULL;
95 if (bits < 512) bits=512;
98 if ((seed_in != NULL) && (seed_len == 20))
99 memcpy(seed,seed_in,seed_len);
102 if (ctx == NULL) goto err;
104 if (ctx2 == NULL) goto err;
106 if (ret == NULL) goto err;
116 BN_lshift(test,BN_value_one(),bits-1);
123 if (callback != NULL) callback(0,m++);
126 RAND_bytes(seed,SHA_DIGEST_LENGTH);
130 memcpy(buf,seed,SHA_DIGEST_LENGTH);
131 memcpy(buf2,seed,SHA_DIGEST_LENGTH);
132 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
135 if (buf[i] != 0) break;
139 HASH(seed,SHA_DIGEST_LENGTH,md);
140 HASH(buf,SHA_DIGEST_LENGTH,buf2);
141 for (i=0; i<SHA_DIGEST_LENGTH; i++)
146 md[SHA_DIGEST_LENGTH-1]|=0x01;
147 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort();
150 if (DSA_is_prime(q,callback) > 0) break;
151 /* do a callback call */
155 if (callback != NULL) callback(2,0);
156 if (callback != NULL) callback(3,0);
170 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
173 if (buf[i] != 0) break;
176 HASH(buf,SHA_DIGEST_LENGTH,md);
179 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort();
180 BN_lshift(r0,r0,160*k);
185 BN_mask_bits(W,bits-1);
186 BN_copy(X,W); /* this should be ok */
187 BN_add(X,X,test); /* this should be ok */
192 BN_sub(r0,c,BN_value_one());
196 if (BN_cmp(p,test) >= 0)
199 if (DSA_is_prime(p,callback) > 0)
207 if (counter >= 4096) break;
209 if (callback != NULL) callback(0,counter);
213 if (callback != NULL) callback(2,1);
215 /* We now need to gernerate g */
217 BN_sub(test,p,BN_value_one());
218 BN_div(r0,NULL,test,q,ctx);
224 BN_mod_exp(g,test,r0,p,ctx);
225 if (!BN_is_one(g)) break;
226 BN_add(test,test,BN_value_one());
230 if (callback != NULL) callback(3,1);
236 if (ret != NULL) DSA_free(ret);
243 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
244 if (counter_ret != NULL) *counter_ret=counter;
245 if (h_ret != NULL) *h_ret=h;
252 int DSA_is_prime(w, callback)
257 BN_CTX *ctx=NULL,*ctx2=NULL;
258 BIGNUM *w_1,*b,*m,*z;
261 if (!BN_is_bit_set(w,0)) return(0);
264 if (ctx == NULL) goto err;
266 if (ctx2 == NULL) goto err;
277 if (!BN_sub(w_1,w,BN_value_one())) goto err;
278 for (a=1; !BN_is_bit_set(w_1,a); a++)
280 if (!BN_rshift(m,w_1,a)) goto err;
282 for (i=1; i < n; i++)
285 BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0);
286 BN_set_word(b,0x10001L);
290 if (!BN_mod_exp(z,b,m,w,ctx)) goto err;
295 if (((j == 0) && BN_is_one(z)) || (BN_cmp(z,w_1) == 0))
299 if ((j > 0) && BN_is_one(z))
312 if (!BN_mod_mul(z,z,z,w,ctx)) goto err;
313 if (callback != NULL) callback(1,j);
319 if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB);