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 /* Parameter generation follows the original release of FIPS PUB 186, 63 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */ 64 #define HASH EVP_sha() 65 #else 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 68 * FIPS PUB 180-1) */ 69 #define HASH EVP_sha1() 70 #endif 71 72 #ifndef OPENSSL_NO_SHA 73 74 #include <stdio.h> 75 #include <time.h> 76 #include "cryptlib.h" 77 #include <openssl/evp.h> 78 #include <openssl/bn.h> 79 #include <openssl/dsa.h> 80 #include <openssl/rand.h> 81 #include <openssl/sha.h> 82 83 #ifndef OPENSSL_FIPS 84 DSA *DSA_generate_parameters(int bits, 85 unsigned char *seed_in, int seed_len, 86 int *counter_ret, unsigned long *h_ret, 87 void (*callback)(int, int, void *), 88 void *cb_arg) 89 { 90 int ok=0; 91 unsigned char seed[SHA_DIGEST_LENGTH]; 92 unsigned char md[SHA_DIGEST_LENGTH]; 93 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH]; 94 BIGNUM *r0,*W,*X,*c,*test; 95 BIGNUM *g=NULL,*q=NULL,*p=NULL; 96 BN_MONT_CTX *mont=NULL; 97 int k,n=0,i,b,m=0; 98 int counter=0; 99 int r=0; 100 BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL; 101 unsigned int h=2; 102 DSA *ret=NULL; 103 104 if (bits < 512) bits=512; 105 bits=(bits+63)/64*64; 106 107 if (seed_len < 20) 108 seed_in = NULL; /* seed buffer too small -- ignore */ 109 if (seed_len > 20) 110 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED, 111 * but our internal buffers are restricted to 160 bits*/ 112 if ((seed_in != NULL) && (seed_len == 20)) 113 memcpy(seed,seed_in,seed_len); 114 115 if ((ctx=BN_CTX_new()) == NULL) goto err; 116 if ((ctx2=BN_CTX_new()) == NULL) goto err; 117 if ((ctx3=BN_CTX_new()) == NULL) goto err; 118 if ((ret=DSA_new()) == NULL) goto err; 119 120 if ((mont=BN_MONT_CTX_new()) == NULL) goto err; 121 122 BN_CTX_start(ctx2); 123 r0 = BN_CTX_get(ctx2); 124 g = BN_CTX_get(ctx2); 125 W = BN_CTX_get(ctx2); 126 q = BN_CTX_get(ctx2); 127 X = BN_CTX_get(ctx2); 128 c = BN_CTX_get(ctx2); 129 p = BN_CTX_get(ctx2); 130 test = BN_CTX_get(ctx2); 131 if (test == NULL) goto err; 132 133 if (!BN_lshift(test,BN_value_one(),bits-1)) goto err; 134 135 for (;;) 136 { 137 for (;;) /* find q */ 138 { 139 int seed_is_random; 140 141 /* step 1 */ 142 if (callback != NULL) callback(0,m++,cb_arg); 143 144 if (!seed_len) 145 { 146 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH); 147 seed_is_random = 1; 148 } 149 else 150 { 151 seed_is_random = 0; 152 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/ 153 } 154 memcpy(buf,seed,SHA_DIGEST_LENGTH); 155 memcpy(buf2,seed,SHA_DIGEST_LENGTH); 156 /* precompute "SEED + 1" for step 7: */ 157 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) 158 { 159 buf[i]++; 160 if (buf[i] != 0) break; 161 } 162 163 /* step 2 */ 164 EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL); 165 EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL); 166 for (i=0; i<SHA_DIGEST_LENGTH; i++) 167 md[i]^=buf2[i]; 168 169 /* step 3 */ 170 md[0]|=0x80; 171 md[SHA_DIGEST_LENGTH-1]|=0x01; 172 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err; 173 174 /* step 4 */ 175 r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, cb_arg, seed_is_random); 176 if (r > 0) 177 break; 178 if (r != 0) 179 goto err; 180 181 /* do a callback call */ 182 /* step 5 */ 183 } 184 185 if (callback != NULL) callback(2,0,cb_arg); 186 if (callback != NULL) callback(3,0,cb_arg); 187 188 /* step 6 */ 189 counter=0; 190 /* "offset = 2" */ 191 192 n=(bits-1)/160; 193 b=(bits-1)-n*160; 194 195 for (;;) 196 { 197 if (callback != NULL && counter != 0) 198 callback(0,counter,cb_arg); 199 200 /* step 7 */ 201 if (!BN_zero(W)) goto err; 202 /* now 'buf' contains "SEED + offset - 1" */ 203 for (k=0; k<=n; k++) 204 { 205 /* obtain "SEED + offset + k" by incrementing: */ 206 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) 207 { 208 buf[i]++; 209 if (buf[i] != 0) break; 210 } 211 212 EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL); 213 214 /* step 8 */ 215 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) 216 goto err; 217 if (!BN_lshift(r0,r0,160*k)) goto err; 218 if (!BN_add(W,W,r0)) goto err; 219 } 220 221 /* more of step 8 */ 222 if (!BN_mask_bits(W,bits-1)) goto err; 223 if (!BN_copy(X,W)) goto err; 224 if (!BN_add(X,X,test)) goto err; 225 226 /* step 9 */ 227 if (!BN_lshift1(r0,q)) goto err; 228 if (!BN_mod(c,X,r0,ctx)) goto err; 229 if (!BN_sub(r0,c,BN_value_one())) goto err; 230 if (!BN_sub(p,X,r0)) goto err; 231 232 /* step 10 */ 233 if (BN_cmp(p,test) >= 0) 234 { 235 /* step 11 */ 236 r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, cb_arg, 1); 237 if (r > 0) 238 goto end; /* found it */ 239 if (r != 0) 240 goto err; 241 } 242 243 /* step 13 */ 244 counter++; 245 /* "offset = offset + n + 1" */ 246 247 /* step 14 */ 248 if (counter >= 4096) break; 249 } 250 } 251 end: 252 if (callback != NULL) callback(2,1,cb_arg); 253 254 /* We now need to generate g */ 255 /* Set r0=(p-1)/q */ 256 if (!BN_sub(test,p,BN_value_one())) goto err; 257 if (!BN_div(r0,NULL,test,q,ctx)) goto err; 258 259 if (!BN_set_word(test,h)) goto err; 260 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err; 261 262 for (;;) 263 { 264 /* g=test^r0%p */ 265 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err; 266 if (!BN_is_one(g)) break; 267 if (!BN_add(test,test,BN_value_one())) goto err; 268 h++; 269 } 270 271 if (callback != NULL) callback(3,1,cb_arg); 272 273 ok=1; 274 err: 275 if (!ok) 276 { 277 if (ret != NULL) DSA_free(ret); 278 } 279 else 280 { 281 ret->p=BN_dup(p); 282 ret->q=BN_dup(q); 283 ret->g=BN_dup(g); 284 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) 285 { 286 ok=0; 287 goto err; 288 } 289 if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20); 290 if (counter_ret != NULL) *counter_ret=counter; 291 if (h_ret != NULL) *h_ret=h; 292 } 293 if (ctx != NULL) BN_CTX_free(ctx); 294 if (ctx2 != NULL) 295 { 296 BN_CTX_end(ctx2); 297 BN_CTX_free(ctx2); 298 } 299 if (ctx3 != NULL) BN_CTX_free(ctx3); 300 if (mont != NULL) BN_MONT_CTX_free(mont); 301 return(ok?ret:NULL); 302 } 303 #endif /* ndef OPENSSL_FIPS */ 304 #endif /* ndef OPENSSL_NO_SHA */ 305 306