wolf SSL / wolfSSL-TLS13-Beta

wolfSSL 3.11.1 for TLS1.3 beta

Fork of wolfSSL by wolf SSL

wolfcrypt/src/dsa.c@13:80fb167dafdf, 2017-05-30 (annotated)

Committer:
wolfSSL
Date:
Tue May 30 06:16:19 2017 +0000
Revision:
13:80fb167dafdf
Parent:
11:cee25a834751 
wolfSSL 3.11.1: TLS1.3 Beta

Who changed what in which revision?

UserRevisionLine numberNew contents of line
wolfSSL 11:cee25a834751 1 /* dsa.c
wolfSSL 11:cee25a834751 2 *
wolfSSL 11:cee25a834751 3 * Copyright (C) 2006-2016 wolfSSL Inc.
wolfSSL 11:cee25a834751 4 *
wolfSSL 11:cee25a834751 5 * This file is part of wolfSSL.
wolfSSL 11:cee25a834751 6 *
wolfSSL 11:cee25a834751 7 * wolfSSL is free software; you can redistribute it and/or modify
wolfSSL 11:cee25a834751 8 * it under the terms of the GNU General Public License as published by
wolfSSL 11:cee25a834751 9 * the Free Software Foundation; either version 2 of the License, or
wolfSSL 11:cee25a834751 10 * (at your option) any later version.
wolfSSL 11:cee25a834751 11 *
wolfSSL 11:cee25a834751 12 * wolfSSL is distributed in the hope that it will be useful,
wolfSSL 11:cee25a834751 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
wolfSSL 11:cee25a834751 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
wolfSSL 11:cee25a834751 15 * GNU General Public License for more details.
wolfSSL 11:cee25a834751 16 *
wolfSSL 11:cee25a834751 17 * You should have received a copy of the GNU General Public License
wolfSSL 11:cee25a834751 18 * along with this program; if not, write to the Free Software
wolfSSL 11:cee25a834751 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
wolfSSL 11:cee25a834751 20 */
wolfSSL 11:cee25a834751 21
wolfSSL 11:cee25a834751 22
wolfSSL 11:cee25a834751 23 #ifdef HAVE_CONFIG_H
wolfSSL 11:cee25a834751 24 #include <config.h>
wolfSSL 11:cee25a834751 25 #endif
wolfSSL 11:cee25a834751 26
wolfSSL 11:cee25a834751 27 #include <wolfssl/wolfcrypt/settings.h>
wolfSSL 11:cee25a834751 28
wolfSSL 11:cee25a834751 29 #ifndef NO_DSA
wolfSSL 11:cee25a834751 30
wolfSSL 11:cee25a834751 31 #include <wolfssl/wolfcrypt/random.h>
wolfSSL 11:cee25a834751 32 #include <wolfssl/wolfcrypt/integer.h>
wolfSSL 11:cee25a834751 33 #include <wolfssl/wolfcrypt/error-crypt.h>
wolfSSL 11:cee25a834751 34 #include <wolfssl/wolfcrypt/logging.h>
wolfSSL 11:cee25a834751 35 #include <wolfssl/wolfcrypt/sha.h>
wolfSSL 11:cee25a834751 36 #include <wolfssl/wolfcrypt/dsa.h>
wolfSSL 11:cee25a834751 37
wolfSSL 11:cee25a834751 38 #ifdef NO_INLINE
wolfSSL 11:cee25a834751 39 #include <wolfssl/wolfcrypt/misc.h>
wolfSSL 11:cee25a834751 40 #else
wolfSSL 11:cee25a834751 41 #define WOLFSSL_MISC_INCLUDED
wolfSSL 11:cee25a834751 42 #include <wolfcrypt/src/misc.c>
wolfSSL 11:cee25a834751 43 #endif
wolfSSL 11:cee25a834751 44
wolfSSL 11:cee25a834751 45
wolfSSL 11:cee25a834751 46 enum {
wolfSSL 11:cee25a834751 47 DSA_HALF_SIZE = 20, /* r and s size */
wolfSSL 11:cee25a834751 48 DSA_SIG_SIZE = 40 /* signature size */
wolfSSL 11:cee25a834751 49 };
wolfSSL 11:cee25a834751 50
wolfSSL 11:cee25a834751 51
wolfSSL 11:cee25a834751 52
wolfSSL 11:cee25a834751 53 int wc_InitDsaKey(DsaKey* key)
wolfSSL 11:cee25a834751 54 {
wolfSSL 11:cee25a834751 55 if (key == NULL)
wolfSSL 11:cee25a834751 56 return BAD_FUNC_ARG;
wolfSSL 11:cee25a834751 57
wolfSSL 11:cee25a834751 58 key->type = -1; /* haven't decided yet */
wolfSSL 11:cee25a834751 59 key->heap = NULL;
wolfSSL 11:cee25a834751 60
wolfSSL 11:cee25a834751 61 return mp_init_multi(
wolfSSL 11:cee25a834751 62 /* public alloc parts */
wolfSSL 11:cee25a834751 63 &key->p,
wolfSSL 11:cee25a834751 64 &key->q,
wolfSSL 11:cee25a834751 65 &key->g,
wolfSSL 11:cee25a834751 66 &key->y,
wolfSSL 11:cee25a834751 67
wolfSSL 11:cee25a834751 68 /* private alloc parts */
wolfSSL 11:cee25a834751 69 &key->x,
wolfSSL 11:cee25a834751 70 NULL
wolfSSL 11:cee25a834751 71 );
wolfSSL 11:cee25a834751 72 }
wolfSSL 11:cee25a834751 73
wolfSSL 11:cee25a834751 74
wolfSSL 11:cee25a834751 75 int wc_InitDsaKey_h(DsaKey* key, void* h)
wolfSSL 11:cee25a834751 76 {
wolfSSL 11:cee25a834751 77 int ret = wc_InitDsaKey(key);
wolfSSL 11:cee25a834751 78 if (ret == 0)
wolfSSL 11:cee25a834751 79 key->heap = h;
wolfSSL 11:cee25a834751 80
wolfSSL 11:cee25a834751 81 return ret;
wolfSSL 11:cee25a834751 82 }
wolfSSL 11:cee25a834751 83
wolfSSL 11:cee25a834751 84
wolfSSL 11:cee25a834751 85 void wc_FreeDsaKey(DsaKey* key)
wolfSSL 11:cee25a834751 86 {
wolfSSL 11:cee25a834751 87 if (key == NULL)
wolfSSL 11:cee25a834751 88 return;
wolfSSL 11:cee25a834751 89
wolfSSL 11:cee25a834751 90 if (key->type == DSA_PRIVATE)
wolfSSL 11:cee25a834751 91 mp_forcezero(&key->x);
wolfSSL 11:cee25a834751 92
wolfSSL 11:cee25a834751 93 #ifndef USE_FAST_MATH
wolfSSL 11:cee25a834751 94 mp_clear(&key->x);
wolfSSL 11:cee25a834751 95 mp_clear(&key->y);
wolfSSL 11:cee25a834751 96 mp_clear(&key->g);
wolfSSL 11:cee25a834751 97 mp_clear(&key->q);
wolfSSL 11:cee25a834751 98 mp_clear(&key->p);
wolfSSL 11:cee25a834751 99 #endif
wolfSSL 11:cee25a834751 100 }
wolfSSL 11:cee25a834751 101
wolfSSL 11:cee25a834751 102 #ifdef WOLFSSL_KEY_GEN
wolfSSL 11:cee25a834751 103
wolfSSL 11:cee25a834751 104 int wc_MakeDsaKey(WC_RNG *rng, DsaKey *dsa)
wolfSSL 11:cee25a834751 105 {
wolfSSL 11:cee25a834751 106 unsigned char *buf;
wolfSSL 11:cee25a834751 107 int qsize, err;
wolfSSL 11:cee25a834751 108
wolfSSL 11:cee25a834751 109 if (rng == NULL || dsa == NULL)
wolfSSL 11:cee25a834751 110 return BAD_FUNC_ARG;
wolfSSL 11:cee25a834751 111
wolfSSL 11:cee25a834751 112 qsize = mp_unsigned_bin_size(&dsa->q);
wolfSSL 11:cee25a834751 113 if (qsize == 0)
wolfSSL 11:cee25a834751 114 return BAD_FUNC_ARG;
wolfSSL 11:cee25a834751 115
wolfSSL 11:cee25a834751 116 /* allocate ram */
wolfSSL 11:cee25a834751 117 buf = (unsigned char *)XMALLOC(qsize, dsa->heap,
wolfSSL 11:cee25a834751 118 DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 119 if (buf == NULL)
wolfSSL 11:cee25a834751 120 return MEMORY_E;
wolfSSL 11:cee25a834751 121
wolfSSL 11:cee25a834751 122 if (mp_init(&dsa->x) != MP_OKAY) {
wolfSSL 11:cee25a834751 123 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 124 return MP_INIT_E;
wolfSSL 11:cee25a834751 125 }
wolfSSL 11:cee25a834751 126
wolfSSL 11:cee25a834751 127 do {
wolfSSL 11:cee25a834751 128 /* make a random exponent mod q */
wolfSSL 11:cee25a834751 129 err = wc_RNG_GenerateBlock(rng, buf, qsize);
wolfSSL 11:cee25a834751 130 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 131 mp_clear(&dsa->x);
wolfSSL 11:cee25a834751 132 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 133 return err;
wolfSSL 11:cee25a834751 134 }
wolfSSL 11:cee25a834751 135
wolfSSL 11:cee25a834751 136 err = mp_read_unsigned_bin(&dsa->x, buf, qsize);
wolfSSL 11:cee25a834751 137 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 138 mp_clear(&dsa->x);
wolfSSL 11:cee25a834751 139 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 140 return err;
wolfSSL 11:cee25a834751 141 }
wolfSSL 11:cee25a834751 142 } while (mp_cmp_d(&dsa->x, 1) != MP_GT);
wolfSSL 11:cee25a834751 143
wolfSSL 11:cee25a834751 144 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 145
wolfSSL 11:cee25a834751 146 if (mp_init(&dsa->y) != MP_OKAY) {
wolfSSL 11:cee25a834751 147 mp_clear(&dsa->x);
wolfSSL 11:cee25a834751 148 return MP_INIT_E;
wolfSSL 11:cee25a834751 149 }
wolfSSL 11:cee25a834751 150
wolfSSL 11:cee25a834751 151 /* public key : y = g^x mod p */
wolfSSL 11:cee25a834751 152 err = mp_exptmod(&dsa->g, &dsa->x, &dsa->p, &dsa->y);
wolfSSL 11:cee25a834751 153 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 154 mp_clear(&dsa->x);
wolfSSL 11:cee25a834751 155 mp_clear(&dsa->y);
wolfSSL 11:cee25a834751 156 return err;
wolfSSL 11:cee25a834751 157 }
wolfSSL 11:cee25a834751 158
wolfSSL 11:cee25a834751 159 dsa->type = DSA_PRIVATE;
wolfSSL 11:cee25a834751 160
wolfSSL 11:cee25a834751 161 return MP_OKAY;
wolfSSL 11:cee25a834751 162 }
wolfSSL 11:cee25a834751 163
wolfSSL 11:cee25a834751 164 /* modulus_size in bits */
wolfSSL 11:cee25a834751 165 int wc_MakeDsaParameters(WC_RNG *rng, int modulus_size, DsaKey *dsa)
wolfSSL 11:cee25a834751 166 {
wolfSSL 11:cee25a834751 167 mp_int tmp, tmp2;
wolfSSL 11:cee25a834751 168 int err, msize, qsize,
wolfSSL 11:cee25a834751 169 loop_check_prime = 0,
wolfSSL 11:cee25a834751 170 check_prime = MP_NO;
wolfSSL 11:cee25a834751 171 unsigned char *buf;
wolfSSL 11:cee25a834751 172
wolfSSL 11:cee25a834751 173 if (rng == NULL || dsa == NULL)
wolfSSL 11:cee25a834751 174 return BAD_FUNC_ARG;
wolfSSL 11:cee25a834751 175
wolfSSL 11:cee25a834751 176 /* set group size in bytes from modulus size
wolfSSL 11:cee25a834751 177 * FIPS 186-4 defines valid values (1024, 160) (2048, 256) (3072, 256)
wolfSSL 11:cee25a834751 178 */
wolfSSL 11:cee25a834751 179 switch (modulus_size) {
wolfSSL 11:cee25a834751 180 case 1024:
wolfSSL 11:cee25a834751 181 qsize = 20;
wolfSSL 11:cee25a834751 182 break;
wolfSSL 11:cee25a834751 183 case 2048:
wolfSSL 11:cee25a834751 184 case 3072:
wolfSSL 11:cee25a834751 185 qsize = 32;
wolfSSL 11:cee25a834751 186 break;
wolfSSL 11:cee25a834751 187 default:
wolfSSL 11:cee25a834751 188 return BAD_FUNC_ARG;
wolfSSL 11:cee25a834751 189 break;
wolfSSL 11:cee25a834751 190 }
wolfSSL 11:cee25a834751 191
wolfSSL 11:cee25a834751 192 /* modulus size in bytes */
wolfSSL 11:cee25a834751 193 msize = modulus_size / 8;
wolfSSL 11:cee25a834751 194
wolfSSL 11:cee25a834751 195 /* allocate ram */
wolfSSL 11:cee25a834751 196 buf = (unsigned char *)XMALLOC(msize - qsize,
wolfSSL 11:cee25a834751 197 dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 198 if (buf == NULL) {
wolfSSL 11:cee25a834751 199 return MEMORY_E;
wolfSSL 11:cee25a834751 200 }
wolfSSL 11:cee25a834751 201
wolfSSL 11:cee25a834751 202 /* make a random string that will be multplied against q */
wolfSSL 11:cee25a834751 203 err = wc_RNG_GenerateBlock(rng, buf, msize - qsize);
wolfSSL 11:cee25a834751 204 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 205 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 206 return err;
wolfSSL 11:cee25a834751 207 }
wolfSSL 11:cee25a834751 208
wolfSSL 11:cee25a834751 209 /* force magnitude */
wolfSSL 11:cee25a834751 210 buf[0] |= 0xC0;
wolfSSL 11:cee25a834751 211
wolfSSL 11:cee25a834751 212 /* force even */
wolfSSL 11:cee25a834751 213 buf[msize - qsize - 1] &= ~1;
wolfSSL 11:cee25a834751 214
wolfSSL 11:cee25a834751 215 if (mp_init_multi(&tmp2, &dsa->p, &dsa->q, 0, 0, 0) != MP_OKAY) {
wolfSSL 11:cee25a834751 216 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 217 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 218 return MP_INIT_E;
wolfSSL 11:cee25a834751 219 }
wolfSSL 11:cee25a834751 220
wolfSSL 11:cee25a834751 221 err = mp_read_unsigned_bin(&tmp2, buf, msize - qsize);
wolfSSL 11:cee25a834751 222 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 223 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 224 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 225 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 226 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 227 return err;
wolfSSL 11:cee25a834751 228 }
wolfSSL 11:cee25a834751 229 XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL 11:cee25a834751 230
wolfSSL 11:cee25a834751 231 /* make our prime q */
wolfSSL 11:cee25a834751 232 err = mp_rand_prime(&dsa->q, qsize, rng, NULL);
wolfSSL 11:cee25a834751 233 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 234 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 235 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 236 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 237 return err;
wolfSSL 11:cee25a834751 238 }
wolfSSL 11:cee25a834751 239
wolfSSL 11:cee25a834751 240 /* p = random * q */
wolfSSL 11:cee25a834751 241 err = mp_mul(&dsa->q, &tmp2, &dsa->p);
wolfSSL 11:cee25a834751 242 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 243 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 244 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 245 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 246 return err;
wolfSSL 11:cee25a834751 247 }
wolfSSL 11:cee25a834751 248
wolfSSL 11:cee25a834751 249 /* p = random * q + 1, so q is a prime divisor of p-1 */
wolfSSL 11:cee25a834751 250 err = mp_add_d(&dsa->p, 1, &dsa->p);
wolfSSL 11:cee25a834751 251 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 252 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 253 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 254 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 255 return err;
wolfSSL 11:cee25a834751 256 }
wolfSSL 11:cee25a834751 257
wolfSSL 11:cee25a834751 258 if (mp_init(&tmp) != MP_OKAY) {
wolfSSL 11:cee25a834751 259 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 260 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 261 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 262 return MP_INIT_E;
wolfSSL 11:cee25a834751 263 }
wolfSSL 11:cee25a834751 264
wolfSSL 11:cee25a834751 265 /* tmp = 2q */
wolfSSL 11:cee25a834751 266 err = mp_add(&dsa->q, &dsa->q, &tmp);
wolfSSL 11:cee25a834751 267 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 268 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 269 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 270 mp_clear(&tmp);
wolfSSL 11:cee25a834751 271 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 272 return err;
wolfSSL 11:cee25a834751 273 }
wolfSSL 11:cee25a834751 274
wolfSSL 11:cee25a834751 275 /* loop until p is prime */
wolfSSL 11:cee25a834751 276 while (check_prime == MP_NO) {
wolfSSL 11:cee25a834751 277 err = mp_prime_is_prime(&dsa->p, 8, &check_prime);
wolfSSL 11:cee25a834751 278 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 279 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 280 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 281 mp_clear(&tmp);
wolfSSL 11:cee25a834751 282 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 283 return err;
wolfSSL 11:cee25a834751 284 }
wolfSSL 11:cee25a834751 285
wolfSSL 11:cee25a834751 286 if (check_prime != MP_YES) {
wolfSSL 11:cee25a834751 287 /* p += 2q */
wolfSSL 11:cee25a834751 288 err = mp_add(&tmp, &dsa->p, &dsa->p);
wolfSSL 11:cee25a834751 289 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 290 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 291 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 292 mp_clear(&tmp);
wolfSSL 11:cee25a834751 293 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 294 return err;
wolfSSL 11:cee25a834751 295 }
wolfSSL 11:cee25a834751 296
wolfSSL 11:cee25a834751 297 loop_check_prime++;
wolfSSL 11:cee25a834751 298 }
wolfSSL 11:cee25a834751 299 }
wolfSSL 11:cee25a834751 300
wolfSSL 11:cee25a834751 301 /* tmp2 += (2*loop_check_prime)
wolfSSL 11:cee25a834751 302 * to have p = (q * tmp2) + 1 prime
wolfSSL 11:cee25a834751 303 */
wolfSSL 11:cee25a834751 304 if (loop_check_prime) {
wolfSSL 11:cee25a834751 305 err = mp_add_d(&tmp2, 2*loop_check_prime, &tmp2);
wolfSSL 11:cee25a834751 306 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 307 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 308 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 309 mp_clear(&tmp);
wolfSSL 11:cee25a834751 310 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 311 return err;
wolfSSL 11:cee25a834751 312 }
wolfSSL 11:cee25a834751 313 }
wolfSSL 11:cee25a834751 314
wolfSSL 11:cee25a834751 315 if (mp_init(&dsa->g) != MP_OKAY) {
wolfSSL 11:cee25a834751 316 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 317 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 318 mp_clear(&tmp);
wolfSSL 11:cee25a834751 319 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 320 return MP_INIT_E;
wolfSSL 11:cee25a834751 321 }
wolfSSL 11:cee25a834751 322
wolfSSL 11:cee25a834751 323 /* find a value g for which g^tmp2 != 1 */
wolfSSL 11:cee25a834751 324 if (mp_set(&dsa->g, 1) != MP_OKAY) {
wolfSSL 11:cee25a834751 325 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 326 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 327 mp_clear(&tmp);
wolfSSL 11:cee25a834751 328 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 329 return MP_INIT_E;
wolfSSL 11:cee25a834751 330 }
wolfSSL 11:cee25a834751 331
wolfSSL 11:cee25a834751 332 do {
wolfSSL 11:cee25a834751 333 err = mp_add_d(&dsa->g, 1, &dsa->g);
wolfSSL 11:cee25a834751 334 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 335 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 336 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 337 mp_clear(&dsa->g);
wolfSSL 11:cee25a834751 338 mp_clear(&tmp);
wolfSSL 11:cee25a834751 339 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 340 return err;
wolfSSL 11:cee25a834751 341 }
wolfSSL 11:cee25a834751 342
wolfSSL 11:cee25a834751 343 err = mp_exptmod(&dsa->g, &tmp2, &dsa->p, &tmp);
wolfSSL 11:cee25a834751 344 if (err != MP_OKAY) {
wolfSSL 11:cee25a834751 345 mp_clear(&dsa->q);
wolfSSL 11:cee25a834751 346 mp_clear(&dsa->p);
wolfSSL 11:cee25a834751 347 mp_clear(&dsa->g);
wolfSSL 11:cee25a834751 348 mp_clear(&tmp);
wolfSSL 11:cee25a834751 349 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 350 return err;
wolfSSL 11:cee25a834751 351 }
wolfSSL 11:cee25a834751 352
wolfSSL 11:cee25a834751 353 } while (mp_cmp_d(&tmp, 1) == MP_EQ);
wolfSSL 11:cee25a834751 354
wolfSSL 11:cee25a834751 355 /* at this point tmp generates a group of order q mod p */
wolfSSL 11:cee25a834751 356 mp_exch(&tmp, &dsa->g);
wolfSSL 11:cee25a834751 357
wolfSSL 11:cee25a834751 358 mp_clear(&tmp);
wolfSSL 11:cee25a834751 359 mp_clear(&tmp2);
wolfSSL 11:cee25a834751 360
wolfSSL 11:cee25a834751 361 return MP_OKAY;
wolfSSL 11:cee25a834751 362 }
wolfSSL 11:cee25a834751 363 #endif /* WOLFSSL_KEY_GEN */
wolfSSL 11:cee25a834751 364
wolfSSL 11:cee25a834751 365
wolfSSL 11:cee25a834751 366 int wc_DsaSign(const byte* digest, byte* out, DsaKey* key, WC_RNG* rng)
wolfSSL 11:cee25a834751 367 {
wolfSSL 11:cee25a834751 368 mp_int k, kInv, r, s, H;
wolfSSL 11:cee25a834751 369 int ret, sz;
wolfSSL 11:cee25a834751 370 byte buffer[DSA_HALF_SIZE];
wolfSSL 11:cee25a834751 371 byte* tmp = out; /* initial output pointer */
wolfSSL 11:cee25a834751 372
wolfSSL 11:cee25a834751 373 sz = min((int)sizeof(buffer), mp_unsigned_bin_size(&key->q));
wolfSSL 11:cee25a834751 374
wolfSSL 11:cee25a834751 375 if (mp_init_multi(&k, &kInv, &r, &s, &H, 0) != MP_OKAY)
wolfSSL 11:cee25a834751 376 return MP_INIT_E;
wolfSSL 11:cee25a834751 377
wolfSSL 11:cee25a834751 378 do {
wolfSSL 11:cee25a834751 379 /* generate k */
wolfSSL 11:cee25a834751 380 ret = wc_RNG_GenerateBlock(rng, buffer, sz);
wolfSSL 11:cee25a834751 381 if (ret != 0)
wolfSSL 11:cee25a834751 382 return ret;
wolfSSL 11:cee25a834751 383
wolfSSL 11:cee25a834751 384 buffer[0] |= 0x0C;
wolfSSL 11:cee25a834751 385
wolfSSL 11:cee25a834751 386 if (mp_read_unsigned_bin(&k, buffer, sz) != MP_OKAY)
wolfSSL 11:cee25a834751 387 ret = MP_READ_E;
wolfSSL 11:cee25a834751 388
wolfSSL 11:cee25a834751 389 /* k is a random numnber and it should be less than q
wolfSSL 11:cee25a834751 390 * if k greater than repeat
wolfSSL 11:cee25a834751 391 */
wolfSSL 11:cee25a834751 392 } while (mp_cmp(&k, &key->q) != MP_LT);
wolfSSL 11:cee25a834751 393
wolfSSL 11:cee25a834751 394 if (ret == 0 && mp_cmp_d(&k, 1) != MP_GT)
wolfSSL 11:cee25a834751 395 ret = MP_CMP_E;
wolfSSL 11:cee25a834751 396
wolfSSL 11:cee25a834751 397 /* inverse k mod q */
wolfSSL 11:cee25a834751 398 if (ret == 0 && mp_invmod(&k, &key->q, &kInv) != MP_OKAY)
wolfSSL 11:cee25a834751 399 ret = MP_INVMOD_E;
wolfSSL 11:cee25a834751 400
wolfSSL 11:cee25a834751 401 /* generate r, r = (g exp k mod p) mod q */
wolfSSL 11:cee25a834751 402 if (ret == 0 && mp_exptmod(&key->g, &k, &key->p, &r) != MP_OKAY)
wolfSSL 11:cee25a834751 403 ret = MP_EXPTMOD_E;
wolfSSL 11:cee25a834751 404
wolfSSL 11:cee25a834751 405 if (ret == 0 && mp_mod(&r, &key->q, &r) != MP_OKAY)
wolfSSL 11:cee25a834751 406 ret = MP_MOD_E;
wolfSSL 11:cee25a834751 407
wolfSSL 11:cee25a834751 408 /* generate H from sha digest */
wolfSSL 11:cee25a834751 409 if (ret == 0 && mp_read_unsigned_bin(&H, digest,SHA_DIGEST_SIZE) != MP_OKAY)
wolfSSL 11:cee25a834751 410 ret = MP_READ_E;
wolfSSL 11:cee25a834751 411
wolfSSL 11:cee25a834751 412 /* generate s, s = (kInv * (H + x*r)) % q */
wolfSSL 11:cee25a834751 413 if (ret == 0 && mp_mul(&key->x, &r, &s) != MP_OKAY)
wolfSSL 11:cee25a834751 414 ret = MP_MUL_E;
wolfSSL 11:cee25a834751 415
wolfSSL 11:cee25a834751 416 if (ret == 0 && mp_add(&s, &H, &s) != MP_OKAY)
wolfSSL 11:cee25a834751 417 ret = MP_ADD_E;
wolfSSL 11:cee25a834751 418
wolfSSL 11:cee25a834751 419 if (ret == 0 && mp_mulmod(&s, &kInv, &key->q, &s) != MP_OKAY)
wolfSSL 11:cee25a834751 420 ret = MP_MULMOD_E;
wolfSSL 11:cee25a834751 421
wolfSSL 11:cee25a834751 422 /* detect zero r or s */
wolfSSL 11:cee25a834751 423 if (ret == 0 && (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES))
wolfSSL 11:cee25a834751 424 ret = MP_ZERO_E;
wolfSSL 11:cee25a834751 425
wolfSSL 11:cee25a834751 426 /* write out */
wolfSSL 11:cee25a834751 427 if (ret == 0) {
wolfSSL 11:cee25a834751 428 int rSz = mp_unsigned_bin_size(&r);
wolfSSL 11:cee25a834751 429 int sSz = mp_unsigned_bin_size(&s);
wolfSSL 11:cee25a834751 430
wolfSSL 11:cee25a834751 431 while (rSz++ < DSA_HALF_SIZE) {
wolfSSL 11:cee25a834751 432 *out++ = 0x00; /* pad front with zeros */
wolfSSL 11:cee25a834751 433 }
wolfSSL 11:cee25a834751 434
wolfSSL 11:cee25a834751 435 if (mp_to_unsigned_bin(&r, out) != MP_OKAY)
wolfSSL 11:cee25a834751 436 ret = MP_TO_E;
wolfSSL 11:cee25a834751 437 else {
wolfSSL 11:cee25a834751 438 out = tmp + DSA_HALF_SIZE; /* advance to s in output */
wolfSSL 11:cee25a834751 439 while (sSz++ < DSA_HALF_SIZE) {
wolfSSL 11:cee25a834751 440 *out++ = 0x00; /* pad front with zeros */
wolfSSL 11:cee25a834751 441 }
wolfSSL 11:cee25a834751 442 ret = mp_to_unsigned_bin(&s, out);
wolfSSL 11:cee25a834751 443 }
wolfSSL 11:cee25a834751 444 }
wolfSSL 11:cee25a834751 445
wolfSSL 11:cee25a834751 446 mp_clear(&H);
wolfSSL 11:cee25a834751 447 mp_clear(&s);
wolfSSL 11:cee25a834751 448 mp_clear(&r);
wolfSSL 11:cee25a834751 449 mp_clear(&kInv);
wolfSSL 11:cee25a834751 450 mp_clear(&k);
wolfSSL 11:cee25a834751 451
wolfSSL 11:cee25a834751 452 return ret;
wolfSSL 11:cee25a834751 453 }
wolfSSL 11:cee25a834751 454
wolfSSL 11:cee25a834751 455
wolfSSL 11:cee25a834751 456 int wc_DsaVerify(const byte* digest, const byte* sig, DsaKey* key, int* answer)
wolfSSL 11:cee25a834751 457 {
wolfSSL 11:cee25a834751 458 mp_int w, u1, u2, v, r, s;
wolfSSL 11:cee25a834751 459 int ret = 0;
wolfSSL 11:cee25a834751 460
wolfSSL 11:cee25a834751 461 if (mp_init_multi(&w, &u1, &u2, &v, &r, &s) != MP_OKAY)
wolfSSL 11:cee25a834751 462 return MP_INIT_E;
wolfSSL 11:cee25a834751 463
wolfSSL 11:cee25a834751 464 /* set r and s from signature */
wolfSSL 11:cee25a834751 465 if (mp_read_unsigned_bin(&r, sig, DSA_HALF_SIZE) != MP_OKAY ||
wolfSSL 11:cee25a834751 466 mp_read_unsigned_bin(&s, sig + DSA_HALF_SIZE, DSA_HALF_SIZE) != MP_OKAY)
wolfSSL 11:cee25a834751 467 ret = MP_READ_E;
wolfSSL 11:cee25a834751 468
wolfSSL 11:cee25a834751 469 /* sanity checks */
wolfSSL 11:cee25a834751 470 if (ret == 0) {
wolfSSL 11:cee25a834751 471 if (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES ||
wolfSSL 11:cee25a834751 472 mp_cmp(&r, &key->q) != MP_LT || mp_cmp(&s, &key->q) != MP_LT) {
wolfSSL 11:cee25a834751 473 ret = MP_ZERO_E;
wolfSSL 11:cee25a834751 474 }
wolfSSL 11:cee25a834751 475 }
wolfSSL 11:cee25a834751 476
wolfSSL 11:cee25a834751 477 /* put H into u1 from sha digest */
wolfSSL 11:cee25a834751 478 if (ret == 0 && mp_read_unsigned_bin(&u1,digest,SHA_DIGEST_SIZE) != MP_OKAY)
wolfSSL 11:cee25a834751 479 ret = MP_READ_E;
wolfSSL 11:cee25a834751 480
wolfSSL 11:cee25a834751 481 /* w = s invmod q */
wolfSSL 11:cee25a834751 482 if (ret == 0 && mp_invmod(&s, &key->q, &w) != MP_OKAY)
wolfSSL 11:cee25a834751 483 ret = MP_INVMOD_E;
wolfSSL 11:cee25a834751 484
wolfSSL 11:cee25a834751 485 /* u1 = (H * w) % q */
wolfSSL 11:cee25a834751 486 if (ret == 0 && mp_mulmod(&u1, &w, &key->q, &u1) != MP_OKAY)
wolfSSL 11:cee25a834751 487 ret = MP_MULMOD_E;
wolfSSL 11:cee25a834751 488
wolfSSL 11:cee25a834751 489 /* u2 = (r * w) % q */
wolfSSL 11:cee25a834751 490 if (ret == 0 && mp_mulmod(&r, &w, &key->q, &u2) != MP_OKAY)
wolfSSL 11:cee25a834751 491 ret = MP_MULMOD_E;
wolfSSL 11:cee25a834751 492
wolfSSL 11:cee25a834751 493 /* verify v = ((g^u1 * y^u2) mod p) mod q */
wolfSSL 11:cee25a834751 494 if (ret == 0 && mp_exptmod(&key->g, &u1, &key->p, &u1) != MP_OKAY)
wolfSSL 11:cee25a834751 495 ret = MP_EXPTMOD_E;
wolfSSL 11:cee25a834751 496
wolfSSL 11:cee25a834751 497 if (ret == 0 && mp_exptmod(&key->y, &u2, &key->p, &u2) != MP_OKAY)
wolfSSL 11:cee25a834751 498 ret = MP_EXPTMOD_E;
wolfSSL 11:cee25a834751 499
wolfSSL 11:cee25a834751 500 if (ret == 0 && mp_mulmod(&u1, &u2, &key->p, &v) != MP_OKAY)
wolfSSL 11:cee25a834751 501 ret = MP_MULMOD_E;
wolfSSL 11:cee25a834751 502
wolfSSL 11:cee25a834751 503 if (ret == 0 && mp_mod(&v, &key->q, &v) != MP_OKAY)
wolfSSL 11:cee25a834751 504 ret = MP_MULMOD_E;
wolfSSL 11:cee25a834751 505
wolfSSL 11:cee25a834751 506 /* do they match */
wolfSSL 11:cee25a834751 507 if (ret == 0 && mp_cmp(&r, &v) == MP_EQ)
wolfSSL 11:cee25a834751 508 *answer = 1;
wolfSSL 11:cee25a834751 509 else
wolfSSL 11:cee25a834751 510 *answer = 0;
wolfSSL 11:cee25a834751 511
wolfSSL 11:cee25a834751 512 mp_clear(&s);
wolfSSL 11:cee25a834751 513 mp_clear(&r);
wolfSSL 11:cee25a834751 514 mp_clear(&u1);
wolfSSL 11:cee25a834751 515 mp_clear(&u2);
wolfSSL 11:cee25a834751 516 mp_clear(&w);
wolfSSL 11:cee25a834751 517 mp_clear(&v);
wolfSSL 11:cee25a834751 518
wolfSSL 11:cee25a834751 519 return ret;
wolfSSL 11:cee25a834751 520 }
wolfSSL 11:cee25a834751 521
wolfSSL 11:cee25a834751 522
wolfSSL 11:cee25a834751 523 #endif /* NO_DSA */
wolfSSL 11:cee25a834751 524
wolfSSL 11:cee25a834751 525