1 /* crypto/dsa/dsa_gen.c */ 2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 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. 8 * 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). 15 * 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. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 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)" 40 * 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 51 * SUCH DAMAGE. 52 * 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.] 57 */ 58 59 #undef GENUINE_DSA 60 61 #ifdef GENUINE_DSA 62 #define HASH SHA 63 #else 64 #define HASH SHA1 65 #endif 66 67 #ifndef NO_SHA 68 #include <stdio.h> 69 #include <time.h> 70 #include "cryptlib.h" 71 #include <openssl/sha.h> 72 #include <openssl/bn.h> 73 #include <openssl/dsa.h> 74 #include <openssl/rand.h> 75 76 DSA *DSA_generate_parameters(int bits, unsigned char *seed_in, int seed_len, 77 int *counter_ret, unsigned long *h_ret, void (*callback)(), 78 char *cb_arg) 79 { 80 int ok=0; 81 unsigned char seed[SHA_DIGEST_LENGTH]; 82 unsigned char md[SHA_DIGEST_LENGTH]; 83 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH]; 84 BIGNUM *r0,*W,*X,*c,*test; 85 BIGNUM *g=NULL,*q=NULL,*p=NULL; 86 BN_MONT_CTX *mont=NULL; 87 int k,n=0,i,b,m=0; 88 int counter=0; 89 BN_CTX *ctx=NULL,*ctx2=NULL; 90 unsigned int h=2; 91 DSA *ret=NULL; 92 93 if (bits < 512) bits=512; 94 bits=(bits+63)/64*64; 95 96 if ((seed_in != NULL) && (seed_len == 20)) 97 memcpy(seed,seed_in,seed_len); 98 99 if ((ctx=BN_CTX_new()) == NULL) goto err; 100 if ((ctx2=BN_CTX_new()) == NULL) goto err; 101 if ((ret=DSA_new()) == NULL) goto err; 102 103 if ((mont=BN_MONT_CTX_new()) == NULL) goto err; 104 105 r0= &(ctx2->bn[0]); 106 g= &(ctx2->bn[1]); 107 W= &(ctx2->bn[2]); 108 q= &(ctx2->bn[3]); 109 X= &(ctx2->bn[4]); 110 c= &(ctx2->bn[5]); 111 p= &(ctx2->bn[6]); 112 test= &(ctx2->bn[7]); 113 114 BN_lshift(test,BN_value_one(),bits-1); 115 116 for (;;) 117 { 118 for (;;) 119 { 120 /* step 1 */ 121 if (callback != NULL) callback(0,m++,cb_arg); 122 123 if (!seed_len) 124 RAND_bytes(seed,SHA_DIGEST_LENGTH); 125 else 126 seed_len=0; 127 128 memcpy(buf,seed,SHA_DIGEST_LENGTH); 129 memcpy(buf2,seed,SHA_DIGEST_LENGTH); 130 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) 131 { 132 buf[i]++; 133 if (buf[i] != 0) break; 134 } 135 136 /* step 2 */ 137 HASH(seed,SHA_DIGEST_LENGTH,md); 138 HASH(buf,SHA_DIGEST_LENGTH,buf2); 139 for (i=0; i<SHA_DIGEST_LENGTH; i++) 140 md[i]^=buf2[i]; 141 142 /* step 3 */ 143 md[0]|=0x80; 144 md[SHA_DIGEST_LENGTH-1]|=0x01; 145 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) abort(); 146 147 /* step 4 */ 148 if (DSA_is_prime(q,callback,cb_arg) > 0) break; 149 /* do a callback call */ 150 /* step 5 */ 151 } 152 153 if (callback != NULL) callback(2,0,cb_arg); 154 if (callback != NULL) callback(3,0,cb_arg); 155 156 /* step 6 */ 157 counter=0; 158 159 n=(bits-1)/160; 160 b=(bits-1)-n*160; 161 162 for (;;) 163 { 164 /* step 7 */ 165 BN_zero(W); 166 for (k=0; k<=n; k++) 167 { 168 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) 169 { 170 buf[i]++; 171 if (buf[i] != 0) break; 172 } 173 174 HASH(buf,SHA_DIGEST_LENGTH,md); 175 176 /* step 8 */ 177 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort(); 178 BN_lshift(r0,r0,160*k); 179 BN_add(W,W,r0); 180 } 181 182 /* more of step 8 */ 183 BN_mask_bits(W,bits-1); 184 BN_copy(X,W); /* this should be ok */ 185 BN_add(X,X,test); /* this should be ok */ 186 187 /* step 9 */ 188 BN_lshift1(r0,q); 189 BN_mod(c,X,r0,ctx); 190 BN_sub(r0,c,BN_value_one()); 191 BN_sub(p,X,r0); 192 193 /* step 10 */ 194 if (BN_cmp(p,test) >= 0) 195 { 196 /* step 11 */ 197 if (DSA_is_prime(p,callback,cb_arg) > 0) 198 goto end; 199 } 200 201 /* step 13 */ 202 counter++; 203 204 /* step 14 */ 205 if (counter >= 4096) break; 206 207 if (callback != NULL) callback(0,counter,cb_arg); 208 } 209 } 210 end: 211 if (callback != NULL) callback(2,1,cb_arg); 212 213 /* We now need to gernerate g */ 214 /* Set r0=(p-1)/q */ 215 BN_sub(test,p,BN_value_one()); 216 BN_div(r0,NULL,test,q,ctx); 217 218 BN_set_word(test,h); 219 BN_MONT_CTX_set(mont,p,ctx); 220 221 for (;;) 222 { 223 /* g=test^r0%p */ 224 BN_mod_exp_mont(g,test,r0,p,ctx,mont); 225 if (!BN_is_one(g)) break; 226 BN_add(test,test,BN_value_one()); 227 h++; 228 } 229 230 if (callback != NULL) callback(3,1,cb_arg); 231 232 ok=1; 233 err: 234 if (!ok) 235 { 236 if (ret != NULL) DSA_free(ret); 237 } 238 else 239 { 240 ret->p=BN_dup(p); 241 ret->q=BN_dup(q); 242 ret->g=BN_dup(g); 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; 246 } 247 if (ctx != NULL) BN_CTX_free(ctx); 248 if (ctx != NULL) BN_CTX_free(ctx2); 249 if (mont != NULL) BN_MONT_CTX_free(mont); 250 return(ok?ret:NULL); 251 } 252 253 int DSA_is_prime(BIGNUM *w, void (*callback)(), char *cb_arg) 254 { 255 int ok= -1,j,i,n; 256 BN_CTX *ctx=NULL,*ctx2=NULL; 257 BIGNUM *w_1,*b,*m,*z,*tmp,*mont_1; 258 int a; 259 BN_MONT_CTX *mont=NULL; 260 261 if (!BN_is_bit_set(w,0)) return(0); 262 263 if ((ctx=BN_CTX_new()) == NULL) goto err; 264 if ((ctx2=BN_CTX_new()) == NULL) goto err; 265 if ((mont=BN_MONT_CTX_new()) == NULL) goto err; 266 267 m= &(ctx2->bn[2]); 268 b= &(ctx2->bn[3]); 269 z= &(ctx2->bn[4]); 270 w_1= &(ctx2->bn[5]); 271 tmp= &(ctx2->bn[6]); 272 mont_1= &(ctx2->bn[7]); 273 274 /* step 1 */ 275 n=50; 276 277 /* step 2 */ 278 if (!BN_sub(w_1,w,BN_value_one())) goto err; 279 for (a=1; !BN_is_bit_set(w_1,a); a++) 280 ; 281 if (!BN_rshift(m,w_1,a)) goto err; 282 283 BN_MONT_CTX_set(mont,w,ctx); 284 BN_to_montgomery(mont_1,BN_value_one(),mont,ctx); 285 BN_to_montgomery(w_1,w_1,mont,ctx); 286 for (i=1; i < n; i++) 287 { 288 /* step 3 */ 289 BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0); 290 /* BN_set_word(b,0x10001L); */ 291 292 /* step 4 */ 293 j=0; 294 if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err; 295 296 if (!BN_to_montgomery(z,z,mont,ctx)) goto err; 297 298 /* step 5 */ 299 for (;;) 300 { 301 if (((j == 0) && (BN_cmp(z,mont_1) == 0)) || 302 (BN_cmp(z,w_1) == 0)) 303 break; 304 305 /* step 6 */ 306 if ((j > 0) && (BN_cmp(z,mont_1) == 0)) 307 { 308 ok=0; 309 goto err; 310 } 311 312 j++; 313 if (j >= a) 314 { 315 ok=0; 316 goto err; 317 } 318 319 if (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err; 320 if (callback != NULL) callback(1,j,cb_arg); 321 } 322 } 323 324 ok=1; 325 err: 326 if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB); 327 BN_CTX_free(ctx); 328 BN_CTX_free(ctx2); 329 BN_MONT_CTX_free(mont); 330 331 return(ok); 332 } 333 #endif 334