| OLD | NEW |
|---|
| (Empty) |
| 1 /* crypto/ec/ec_mult.c */ | |
| 2 /* | |
| 3 * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project. | |
| 4 */ | |
| 5 /* ==================================================================== | |
| 6 * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. | |
| 7 * | |
| 8 * Redistribution and use in source and binary forms, with or without | |
| 9 * modification, are permitted provided that the following conditions | |
| 10 * are met: | |
| 11 * | |
| 12 * 1. Redistributions of source code must retain the above copyright | |
| 13 * notice, this list of conditions and the following disclaimer. | |
| 14 * | |
| 15 * 2. Redistributions in binary form must reproduce the above copyright | |
| 16 * notice, this list of conditions and the following disclaimer in | |
| 17 * the documentation and/or other materials provided with the | |
| 18 * distribution. | |
| 19 * | |
| 20 * 3. All advertising materials mentioning features or use of this | |
| 21 * software must display the following acknowledgment: | |
| 22 * "This product includes software developed by the OpenSSL Project | |
| 23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |
| 24 * | |
| 25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
| 26 * endorse or promote products derived from this software without | |
| 27 * prior written permission. For written permission, please contact | |
| 28 * openssl-core@openssl.org. | |
| 29 * | |
| 30 * 5. Products derived from this software may not be called "OpenSSL" | |
| 31 * nor may "OpenSSL" appear in their names without prior written | |
| 32 * permission of the OpenSSL Project. | |
| 33 * | |
| 34 * 6. Redistributions of any form whatsoever must retain the following | |
| 35 * acknowledgment: | |
| 36 * "This product includes software developed by the OpenSSL Project | |
| 37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |
| 38 * | |
| 39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
| 40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
| 42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
| 43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
| 48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
| 50 * OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 51 * ==================================================================== | |
| 52 * | |
| 53 * This product includes cryptographic software written by Eric Young | |
| 54 * (eay@cryptsoft.com). This product includes software written by Tim | |
| 55 * Hudson (tjh@cryptsoft.com). | |
| 56 * | |
| 57 */ | |
| 58 /* ==================================================================== | |
| 59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. | |
| 60 * Portions of this software developed by SUN MICROSYSTEMS, INC., | |
| 61 * and contributed to the OpenSSL project. | |
| 62 */ | |
| 63 | |
| 64 #include <string.h> | |
| 65 | |
| 66 #include <openssl/err.h> | |
| 67 | |
| 68 #include "ec_lcl.h" | |
| 69 | |
| 70 | |
| 71 /* | |
| 72 * This file implements the wNAF-based interleaving multi-exponentation method | |
| 73 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multi
exp>); | |
| 74 * for multiplication with precomputation, we use wNAF splitting | |
| 75 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#faste
xp>). | |
| 76 */ | |
| 77 | |
| 78 | |
| 79 | |
| 80 | |
| 81 /* structure for precomputed multiples of the generator */ | |
| 82 typedef struct ec_pre_comp_st { | |
| 83 const EC_GROUP *group; /* parent EC_GROUP object */ | |
| 84 size_t blocksize; /* block size for wNAF splitting */ | |
| 85 size_t numblocks; /* max. number of blocks for which we have precom
putation */ | |
| 86 size_t w; /* window size */ | |
| 87 EC_POINT **points; /* array with pre-calculated multiples of generat
or: | |
| 88 * 'num' pointers to EC_POINT objects followed by
a NULL */ | |
| 89 size_t num; /* numblocks * 2^(w-1) */ | |
| 90 int references; | |
| 91 } EC_PRE_COMP; | |
| 92 | |
| 93 /* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */ | |
| 94 static void *ec_pre_comp_dup(void *); | |
| 95 static void ec_pre_comp_free(void *); | |
| 96 static void ec_pre_comp_clear_free(void *); | |
| 97 | |
| 98 static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group) | |
| 99 { | |
| 100 EC_PRE_COMP *ret = NULL; | |
| 101 | |
| 102 if (!group) | |
| 103 return NULL; | |
| 104 | |
| 105 ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); | |
| 106 if (!ret) | |
| 107 { | |
| 108 ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE); | |
| 109 return ret; | |
| 110 } | |
| 111 ret->group = group; | |
| 112 ret->blocksize = 8; /* default */ | |
| 113 ret->numblocks = 0; | |
| 114 ret->w = 4; /* default */ | |
| 115 ret->points = NULL; | |
| 116 ret->num = 0; | |
| 117 ret->references = 1; | |
| 118 return ret; | |
| 119 } | |
| 120 | |
| 121 static void *ec_pre_comp_dup(void *src_) | |
| 122 { | |
| 123 EC_PRE_COMP *src = src_; | |
| 124 | |
| 125 /* no need to actually copy, these objects never change! */ | |
| 126 | |
| 127 CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP); | |
| 128 | |
| 129 return src_; | |
| 130 } | |
| 131 | |
| 132 static void ec_pre_comp_free(void *pre_) | |
| 133 { | |
| 134 int i; | |
| 135 EC_PRE_COMP *pre = pre_; | |
| 136 | |
| 137 if (!pre) | |
| 138 return; | |
| 139 | |
| 140 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); | |
| 141 if (i > 0) | |
| 142 return; | |
| 143 | |
| 144 if (pre->points) | |
| 145 { | |
| 146 EC_POINT **p; | |
| 147 | |
| 148 for (p = pre->points; *p != NULL; p++) | |
| 149 EC_POINT_free(*p); | |
| 150 OPENSSL_free(pre->points); | |
| 151 } | |
| 152 OPENSSL_free(pre); | |
| 153 } | |
| 154 | |
| 155 static void ec_pre_comp_clear_free(void *pre_) | |
| 156 { | |
| 157 int i; | |
| 158 EC_PRE_COMP *pre = pre_; | |
| 159 | |
| 160 if (!pre) | |
| 161 return; | |
| 162 | |
| 163 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); | |
| 164 if (i > 0) | |
| 165 return; | |
| 166 | |
| 167 if (pre->points) | |
| 168 { | |
| 169 EC_POINT **p; | |
| 170 | |
| 171 for (p = pre->points; *p != NULL; p++) | |
| 172 { | |
| 173 EC_POINT_clear_free(*p); | |
| 174 OPENSSL_cleanse(p, sizeof *p); | |
| 175 } | |
| 176 OPENSSL_free(pre->points); | |
| 177 } | |
| 178 OPENSSL_cleanse(pre, sizeof *pre); | |
| 179 OPENSSL_free(pre); | |
| 180 } | |
| 181 | |
| 182 | |
| 183 | |
| 184 | |
| 185 /* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. | |
| 186 * This is an array r[] of values that are either zero or odd with an | |
| 187 * absolute value less than 2^w satisfying | |
| 188 * scalar = \sum_j r[j]*2^j | |
| 189 * where at most one of any w+1 consecutive digits is non-zero | |
| 190 * with the exception that the most significant digit may be only | |
| 191 * w-1 zeros away from that next non-zero digit. | |
| 192 */ | |
| 193 static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len) | |
| 194 { | |
| 195 int window_val; | |
| 196 int ok = 0; | |
| 197 signed char *r = NULL; | |
| 198 int sign = 1; | |
| 199 int bit, next_bit, mask; | |
| 200 size_t len = 0, j; | |
| 201 | |
| 202 if (BN_is_zero(scalar)) | |
| 203 { | |
| 204 r = OPENSSL_malloc(1); | |
| 205 if (!r) | |
| 206 { | |
| 207 ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); | |
| 208 goto err; | |
| 209 } | |
| 210 r[0] = 0; | |
| 211 *ret_len = 1; | |
| 212 return r; | |
| 213 } | |
| 214 | |
| 215 if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolu
te values less than 2^7 */ | |
| 216 { | |
| 217 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 218 goto err; | |
| 219 } | |
| 220 bit = 1 << w; /* at most 128 */ | |
| 221 next_bit = bit << 1; /* at most 256 */ | |
| 222 mask = next_bit - 1; /* at most 255 */ | |
| 223 | |
| 224 if (BN_is_negative(scalar)) | |
| 225 { | |
| 226 sign = -1; | |
| 227 } | |
| 228 | |
| 229 if (scalar->d == NULL || scalar->top == 0) | |
| 230 { | |
| 231 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 232 goto err; | |
| 233 } | |
| 234 | |
| 235 len = BN_num_bits(scalar); | |
| 236 r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer th
an binary representation | |
| 237 * (*ret_len will be set to the actual leng
th, i.e. at most | |
| 238 * BN_num_bits(scalar) + 1) */ | |
| 239 if (r == NULL) | |
| 240 { | |
| 241 ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); | |
| 242 goto err; | |
| 243 } | |
| 244 window_val = scalar->d[0] & mask; | |
| 245 j = 0; | |
| 246 while ((window_val != 0) || (j + w + 1 < len)) /* if j+w+1 >= len, windo
w_val will not increase */ | |
| 247 { | |
| 248 int digit = 0; | |
| 249 | |
| 250 /* 0 <= window_val <= 2^(w+1) */ | |
| 251 | |
| 252 if (window_val & 1) | |
| 253 { | |
| 254 /* 0 < window_val < 2^(w+1) */ | |
| 255 | |
| 256 if (window_val & bit) | |
| 257 { | |
| 258 digit = window_val - next_bit; /* -2^w < digit <
0 */ | |
| 259 | |
| 260 #if 1 /* modified wNAF */ | |
| 261 if (j + w + 1 >= len) | |
| 262 { | |
| 263 /* special case for generating modified
wNAFs: | |
| 264 * no new bits will be added into window
_val, | |
| 265 * so using a positive digit here will d
ecrease | |
| 266 * the total length of the representatio
n */ | |
| 267 | |
| 268 digit = window_val & (mask >> 1); /* 0 <
digit < 2^w */ | |
| 269 } | |
| 270 #endif | |
| 271 } | |
| 272 else | |
| 273 { | |
| 274 digit = window_val; /* 0 < digit < 2^w */ | |
| 275 } | |
| 276 | |
| 277 if (digit <= -bit || digit >= bit || !(digit & 1)) | |
| 278 { | |
| 279 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 280 goto err; | |
| 281 } | |
| 282 | |
| 283 window_val -= digit; | |
| 284 | |
| 285 /* now window_val is 0 or 2^(w+1) in standard wNAF gener
ation; | |
| 286 * for modified window NAFs, it may also be 2^w | |
| 287 */ | |
| 288 if (window_val != 0 && window_val != next_bit && window_
val != bit) | |
| 289 { | |
| 290 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 291 goto err; | |
| 292 } | |
| 293 } | |
| 294 | |
| 295 r[j++] = sign * digit; | |
| 296 | |
| 297 window_val >>= 1; | |
| 298 window_val += bit * BN_is_bit_set(scalar, j + w); | |
| 299 | |
| 300 if (window_val > next_bit) | |
| 301 { | |
| 302 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 303 goto err; | |
| 304 } | |
| 305 } | |
| 306 | |
| 307 if (j > len + 1) | |
| 308 { | |
| 309 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); | |
| 310 goto err; | |
| 311 } | |
| 312 len = j; | |
| 313 ok = 1; | |
| 314 | |
| 315 err: | |
| 316 if (!ok) | |
| 317 { | |
| 318 OPENSSL_free(r); | |
| 319 r = NULL; | |
| 320 } | |
| 321 if (ok) | |
| 322 *ret_len = len; | |
| 323 return r; | |
| 324 } | |
| 325 | |
| 326 | |
| 327 /* TODO: table should be optimised for the wNAF-based implementation, | |
| 328 * sometimes smaller windows will give better performance | |
| 329 * (thus the boundaries should be increased) | |
| 330 */ | |
| 331 #define EC_window_bits_for_scalar_size(b) \ | |
| 332 ((size_t) \ | |
| 333 ((b) >= 2000 ? 6 : \ | |
| 334 (b) >= 800 ? 5 : \ | |
| 335 (b) >= 300 ? 4 : \ | |
| 336 (b) >= 70 ? 3 : \ | |
| 337 (b) >= 20 ? 2 : \ | |
| 338 1)) | |
| 339 | |
| 340 /* Compute | |
| 341 * \sum scalars[i]*points[i], | |
| 342 * also including | |
| 343 * scalar*generator | |
| 344 * in the addition if scalar != NULL | |
| 345 */ | |
| 346 int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, | |
| 347 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *c
tx) | |
| 348 { | |
| 349 BN_CTX *new_ctx = NULL; | |
| 350 const EC_POINT *generator = NULL; | |
| 351 EC_POINT *tmp = NULL; | |
| 352 size_t totalnum; | |
| 353 size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */ | |
| 354 size_t pre_points_per_block = 0; | |
| 355 size_t i, j; | |
| 356 int k; | |
| 357 int r_is_inverted = 0; | |
| 358 int r_is_at_infinity = 1; | |
| 359 size_t *wsize = NULL; /* individual window sizes */ | |
| 360 signed char **wNAF = NULL; /* individual wNAFs */ | |
| 361 size_t *wNAF_len = NULL; | |
| 362 size_t max_len = 0; | |
| 363 size_t num_val; | |
| 364 EC_POINT **val = NULL; /* precomputation */ | |
| 365 EC_POINT **v; | |
| 366 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or 'pre_c
omp->points' */ | |
| 367 const EC_PRE_COMP *pre_comp = NULL; | |
| 368 int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treate
d like other scalars, | |
| 369 * i.e. precomputation is not available */ | |
| 370 int ret = 0; | |
| 371 | |
| 372 if (group->meth != r->meth) | |
| 373 { | |
| 374 ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); | |
| 375 return 0; | |
| 376 } | |
| 377 | |
| 378 if ((scalar == NULL) && (num == 0)) | |
| 379 { | |
| 380 return EC_POINT_set_to_infinity(group, r); | |
| 381 } | |
| 382 | |
| 383 for (i = 0; i < num; i++) | |
| 384 { | |
| 385 if (group->meth != points[i]->meth) | |
| 386 { | |
| 387 ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); | |
| 388 return 0; | |
| 389 } | |
| 390 } | |
| 391 | |
| 392 if (ctx == NULL) | |
| 393 { | |
| 394 ctx = new_ctx = BN_CTX_new(); | |
| 395 if (ctx == NULL) | |
| 396 goto err; | |
| 397 } | |
| 398 | |
| 399 if (scalar != NULL) | |
| 400 { | |
| 401 generator = EC_GROUP_get0_generator(group); | |
| 402 if (generator == NULL) | |
| 403 { | |
| 404 ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR); | |
| 405 goto err; | |
| 406 } | |
| 407 | |
| 408 /* look if we can use precomputed multiples of generator */ | |
| 409 | |
| 410 pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_du
p, ec_pre_comp_free, ec_pre_comp_clear_free); | |
| 411 | |
| 412 if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, gene
rator, pre_comp->points[0], ctx) == 0)) | |
| 413 { | |
| 414 blocksize = pre_comp->blocksize; | |
| 415 | |
| 416 /* determine maximum number of blocks that wNAF splittin
g may yield | |
| 417 * (NB: maximum wNAF length is bit length plus one) */ | |
| 418 numblocks = (BN_num_bits(scalar) / blocksize) + 1; | |
| 419 | |
| 420 /* we cannot use more blocks than we have precomputation
for */ | |
| 421 if (numblocks > pre_comp->numblocks) | |
| 422 numblocks = pre_comp->numblocks; | |
| 423 | |
| 424 pre_points_per_block = (size_t)1 << (pre_comp->w - 1); | |
| 425 | |
| 426 /* check that pre_comp looks sane */ | |
| 427 if (pre_comp->num != (pre_comp->numblocks * pre_points_p
er_block)) | |
| 428 { | |
| 429 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
| 430 goto err; | |
| 431 } | |
| 432 } | |
| 433 else | |
| 434 { | |
| 435 /* can't use precomputation */ | |
| 436 pre_comp = NULL; | |
| 437 numblocks = 1; | |
| 438 num_scalar = 1; /* treat 'scalar' like 'num'-th element
of 'scalars' */ | |
| 439 } | |
| 440 } | |
| 441 | |
| 442 totalnum = num + numblocks; | |
| 443 | |
| 444 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); | |
| 445 wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); | |
| 446 wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes
space for pivot */ | |
| 447 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); | |
| 448 | |
| 449 if (!wsize || !wNAF_len || !wNAF || !val_sub) | |
| 450 { | |
| 451 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); | |
| 452 goto err; | |
| 453 } | |
| 454 | |
| 455 wNAF[0] = NULL; /* preliminary pivot */ | |
| 456 | |
| 457 /* num_val will be the total number of temporarily precomputed points */ | |
| 458 num_val = 0; | |
| 459 | |
| 460 for (i = 0; i < num + num_scalar; i++) | |
| 461 { | |
| 462 size_t bits; | |
| 463 | |
| 464 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); | |
| 465 wsize[i] = EC_window_bits_for_scalar_size(bits); | |
| 466 num_val += (size_t)1 << (wsize[i] - 1); | |
| 467 wNAF[i + 1] = NULL; /* make sure we always have a pivot */ | |
| 468 wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i]
, &wNAF_len[i]); | |
| 469 if (wNAF[i] == NULL) | |
| 470 goto err; | |
| 471 if (wNAF_len[i] > max_len) | |
| 472 max_len = wNAF_len[i]; | |
| 473 } | |
| 474 | |
| 475 if (numblocks) | |
| 476 { | |
| 477 /* we go here iff scalar != NULL */ | |
| 478 | |
| 479 if (pre_comp == NULL) | |
| 480 { | |
| 481 if (num_scalar != 1) | |
| 482 { | |
| 483 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
| 484 goto err; | |
| 485 } | |
| 486 /* we have already generated a wNAF for 'scalar' */ | |
| 487 } | |
| 488 else | |
| 489 { | |
| 490 signed char *tmp_wNAF = NULL; | |
| 491 size_t tmp_len = 0; | |
| 492 | |
| 493 if (num_scalar != 0) | |
| 494 { | |
| 495 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
| 496 goto err; | |
| 497 } | |
| 498 | |
| 499 /* use the window size for which we have precomputation
*/ | |
| 500 wsize[num] = pre_comp->w; | |
| 501 tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len); | |
| 502 if (!tmp_wNAF) | |
| 503 goto err; | |
| 504 | |
| 505 if (tmp_len <= max_len) | |
| 506 { | |
| 507 /* One of the other wNAFs is at least as long | |
| 508 * as the wNAF belonging to the generator, | |
| 509 * so wNAF splitting will not buy us anything. *
/ | |
| 510 | |
| 511 numblocks = 1; | |
| 512 totalnum = num + 1; /* don't use wNAF splitting
*/ | |
| 513 wNAF[num] = tmp_wNAF; | |
| 514 wNAF[num + 1] = NULL; | |
| 515 wNAF_len[num] = tmp_len; | |
| 516 if (tmp_len > max_len) | |
| 517 max_len = tmp_len; | |
| 518 /* pre_comp->points starts with the points that
we need here: */ | |
| 519 val_sub[num] = pre_comp->points; | |
| 520 } | |
| 521 else | |
| 522 { | |
| 523 /* don't include tmp_wNAF directly into wNAF arr
ay | |
| 524 * - use wNAF splitting and include the blocks *
/ | |
| 525 | |
| 526 signed char *pp; | |
| 527 EC_POINT **tmp_points; | |
| 528 | |
| 529 if (tmp_len < numblocks * blocksize) | |
| 530 { | |
| 531 /* possibly we can do with fewer blocks
than estimated */ | |
| 532 numblocks = (tmp_len + blocksize - 1) /
blocksize; | |
| 533 if (numblocks > pre_comp->numblocks) | |
| 534 { | |
| 535 ECerr(EC_F_EC_WNAF_MUL, ERR_R_IN
TERNAL_ERROR); | |
| 536 goto err; | |
| 537 } | |
| 538 totalnum = num + numblocks; | |
| 539 } | |
| 540 | |
| 541 /* split wNAF in 'numblocks' parts */ | |
| 542 pp = tmp_wNAF; | |
| 543 tmp_points = pre_comp->points; | |
| 544 | |
| 545 for (i = num; i < totalnum; i++) | |
| 546 { | |
| 547 if (i < totalnum - 1) | |
| 548 { | |
| 549 wNAF_len[i] = blocksize; | |
| 550 if (tmp_len < blocksize) | |
| 551 { | |
| 552 ECerr(EC_F_EC_WNAF_MUL,
ERR_R_INTERNAL_ERROR); | |
| 553 goto err; | |
| 554 } | |
| 555 tmp_len -= blocksize; | |
| 556 } | |
| 557 else | |
| 558 /* last block gets whatever is l
eft | |
| 559 * (this could be more or less t
han 'blocksize'!) */ | |
| 560 wNAF_len[i] = tmp_len; | |
| 561 | |
| 562 wNAF[i + 1] = NULL; | |
| 563 wNAF[i] = OPENSSL_malloc(wNAF_len[i]); | |
| 564 if (wNAF[i] == NULL) | |
| 565 { | |
| 566 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MA
LLOC_FAILURE); | |
| 567 OPENSSL_free(tmp_wNAF); | |
| 568 goto err; | |
| 569 } | |
| 570 memcpy(wNAF[i], pp, wNAF_len[i]); | |
| 571 if (wNAF_len[i] > max_len) | |
| 572 max_len = wNAF_len[i]; | |
| 573 | |
| 574 if (*tmp_points == NULL) | |
| 575 { | |
| 576 ECerr(EC_F_EC_WNAF_MUL, ERR_R_IN
TERNAL_ERROR); | |
| 577 OPENSSL_free(tmp_wNAF); | |
| 578 goto err; | |
| 579 } | |
| 580 val_sub[i] = tmp_points; | |
| 581 tmp_points += pre_points_per_block; | |
| 582 pp += blocksize; | |
| 583 } | |
| 584 OPENSSL_free(tmp_wNAF); | |
| 585 } | |
| 586 } | |
| 587 } | |
| 588 | |
| 589 /* All points we precompute now go into a single array 'val'. | |
| 590 * 'val_sub[i]' is a pointer to the subarray for the i-th point, | |
| 591 * or to a subarray of 'pre_comp->points' if we already have precomputat
ion. */ | |
| 592 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); | |
| 593 if (val == NULL) | |
| 594 { | |
| 595 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); | |
| 596 goto err; | |
| 597 } | |
| 598 val[num_val] = NULL; /* pivot element */ | |
| 599 | |
| 600 /* allocate points for precomputation */ | |
| 601 v = val; | |
| 602 for (i = 0; i < num + num_scalar; i++) | |
| 603 { | |
| 604 val_sub[i] = v; | |
| 605 for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) | |
| 606 { | |
| 607 *v = EC_POINT_new(group); | |
| 608 if (*v == NULL) goto err; | |
| 609 v++; | |
| 610 } | |
| 611 } | |
| 612 if (!(v == val + num_val)) | |
| 613 { | |
| 614 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
| 615 goto err; | |
| 616 } | |
| 617 | |
| 618 if (!(tmp = EC_POINT_new(group))) | |
| 619 goto err; | |
| 620 | |
| 621 /* prepare precomputed values: | |
| 622 * val_sub[i][0] := points[i] | |
| 623 * val_sub[i][1] := 3 * points[i] | |
| 624 * val_sub[i][2] := 5 * points[i] | |
| 625 * ... | |
| 626 */ | |
| 627 for (i = 0; i < num + num_scalar; i++) | |
| 628 { | |
| 629 if (i < num) | |
| 630 { | |
| 631 if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err; | |
| 632 } | |
| 633 else | |
| 634 { | |
| 635 if (!EC_POINT_copy(val_sub[i][0], generator)) goto err; | |
| 636 } | |
| 637 | |
| 638 if (wsize[i] > 1) | |
| 639 { | |
| 640 if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto
err; | |
| 641 for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) | |
| 642 { | |
| 643 if (!EC_POINT_add(group, val_sub[i][j], val_sub[
i][j - 1], tmp, ctx)) goto err; | |
| 644 } | |
| 645 } | |
| 646 } | |
| 647 | |
| 648 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ | |
| 649 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) | |
| 650 goto err; | |
| 651 #endif | |
| 652 | |
| 653 r_is_at_infinity = 1; | |
| 654 | |
| 655 for (k = max_len - 1; k >= 0; k--) | |
| 656 { | |
| 657 if (!r_is_at_infinity) | |
| 658 { | |
| 659 if (!EC_POINT_dbl(group, r, r, ctx)) goto err; | |
| 660 } | |
| 661 | |
| 662 for (i = 0; i < totalnum; i++) | |
| 663 { | |
| 664 if (wNAF_len[i] > (size_t)k) | |
| 665 { | |
| 666 int digit = wNAF[i][k]; | |
| 667 int is_neg; | |
| 668 | |
| 669 if (digit) | |
| 670 { | |
| 671 is_neg = digit < 0; | |
| 672 | |
| 673 if (is_neg) | |
| 674 digit = -digit; | |
| 675 | |
| 676 if (is_neg != r_is_inverted) | |
| 677 { | |
| 678 if (!r_is_at_infinity) | |
| 679 { | |
| 680 if (!EC_POINT_invert(gro
up, r, ctx)) goto err; | |
| 681 } | |
| 682 r_is_inverted = !r_is_inverted; | |
| 683 } | |
| 684 | |
| 685 /* digit > 0 */ | |
| 686 | |
| 687 if (r_is_at_infinity) | |
| 688 { | |
| 689 if (!EC_POINT_copy(r, val_sub[i]
[digit >> 1])) goto err; | |
| 690 r_is_at_infinity = 0; | |
| 691 } | |
| 692 else | |
| 693 { | |
| 694 if (!EC_POINT_add(group, r, r, v
al_sub[i][digit >> 1], ctx)) goto err; | |
| 695 } | |
| 696 } | |
| 697 } | |
| 698 } | |
| 699 } | |
| 700 | |
| 701 if (r_is_at_infinity) | |
| 702 { | |
| 703 if (!EC_POINT_set_to_infinity(group, r)) goto err; | |
| 704 } | |
| 705 else | |
| 706 { | |
| 707 if (r_is_inverted) | |
| 708 if (!EC_POINT_invert(group, r, ctx)) goto err; | |
| 709 } | |
| 710 | |
| 711 ret = 1; | |
| 712 | |
| 713 err: | |
| 714 if (new_ctx != NULL) | |
| 715 BN_CTX_free(new_ctx); | |
| 716 if (tmp != NULL) | |
| 717 EC_POINT_free(tmp); | |
| 718 if (wsize != NULL) | |
| 719 OPENSSL_free(wsize); | |
| 720 if (wNAF_len != NULL) | |
| 721 OPENSSL_free(wNAF_len); | |
| 722 if (wNAF != NULL) | |
| 723 { | |
| 724 signed char **w; | |
| 725 | |
| 726 for (w = wNAF; *w != NULL; w++) | |
| 727 OPENSSL_free(*w); | |
| 728 | |
| 729 OPENSSL_free(wNAF); | |
| 730 } | |
| 731 if (val != NULL) | |
| 732 { | |
| 733 for (v = val; *v != NULL; v++) | |
| 734 EC_POINT_clear_free(*v); | |
| 735 | |
| 736 OPENSSL_free(val); | |
| 737 } | |
| 738 if (val_sub != NULL) | |
| 739 { | |
| 740 OPENSSL_free(val_sub); | |
| 741 } | |
| 742 return ret; | |
| 743 } | |
| 744 | |
| 745 | |
| 746 /* ec_wNAF_precompute_mult() | |
| 747 * creates an EC_PRE_COMP object with preprecomputed multiples of the generator | |
| 748 * for use with wNAF splitting as implemented in ec_wNAF_mul(). | |
| 749 * | |
| 750 * 'pre_comp->points' is an array of multiples of the generator | |
| 751 * of the following form: | |
| 752 * points[0] = generator; | |
| 753 * points[1] = 3 * generator; | |
| 754 * ... | |
| 755 * points[2^(w-1)-1] = (2^(w-1)-1) * generator; | |
| 756 * points[2^(w-1)] = 2^blocksize * generator; | |
| 757 * points[2^(w-1)+1] = 3 * 2^blocksize * generator; | |
| 758 * ... | |
| 759 * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) *
generator | |
| 760 * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) *
generator | |
| 761 * ... | |
| 762 * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) *
generator | |
| 763 * points[2^(w-1)*numblocks] = NULL | |
| 764 */ | |
| 765 int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx) | |
| 766 { | |
| 767 const EC_POINT *generator; | |
| 768 EC_POINT *tmp_point = NULL, *base = NULL, **var; | |
| 769 BN_CTX *new_ctx = NULL; | |
| 770 BIGNUM *order; | |
| 771 size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num; | |
| 772 EC_POINT **points = NULL; | |
| 773 EC_PRE_COMP *pre_comp; | |
| 774 int ret = 0; | |
| 775 | |
| 776 /* if there is an old EC_PRE_COMP object, throw it away */ | |
| 777 EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_fr
ee, ec_pre_comp_clear_free); | |
| 778 | |
| 779 if ((pre_comp = ec_pre_comp_new(group)) == NULL) | |
| 780 return 0; | |
| 781 | |
| 782 generator = EC_GROUP_get0_generator(group); | |
| 783 if (generator == NULL) | |
| 784 { | |
| 785 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR); | |
| 786 goto err; | |
| 787 } | |
| 788 | |
| 789 if (ctx == NULL) | |
| 790 { | |
| 791 ctx = new_ctx = BN_CTX_new(); | |
| 792 if (ctx == NULL) | |
| 793 goto err; | |
| 794 } | |
| 795 | |
| 796 BN_CTX_start(ctx); | |
| 797 order = BN_CTX_get(ctx); | |
| 798 if (order == NULL) goto err; | |
| 799 | |
| 800 if (!EC_GROUP_get_order(group, order, ctx)) goto err; | |
| 801 if (BN_is_zero(order)) | |
| 802 { | |
| 803 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER); | |
| 804 goto err; | |
| 805 } | |
| 806 | |
| 807 bits = BN_num_bits(order); | |
| 808 /* The following parameters mean we precompute (approximately) | |
| 809 * one point per bit. | |
| 810 * | |
| 811 * TBD: The combination 8, 4 is perfect for 160 bits; for other | |
| 812 * bit lengths, other parameter combinations might provide better | |
| 813 * efficiency. | |
| 814 */ | |
| 815 blocksize = 8; | |
| 816 w = 4; | |
| 817 if (EC_window_bits_for_scalar_size(bits) > w) | |
| 818 { | |
| 819 /* let's not make the window too small ... */ | |
| 820 w = EC_window_bits_for_scalar_size(bits); | |
| 821 } | |
| 822 | |
| 823 numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks
to use for wNAF splitting */ | |
| 824 | |
| 825 pre_points_per_block = (size_t)1 << (w - 1); | |
| 826 num = pre_points_per_block * numblocks; /* number of points to compute a
nd store */ | |
| 827 | |
| 828 points = OPENSSL_malloc(sizeof (EC_POINT*)*(num + 1)); | |
| 829 if (!points) | |
| 830 { | |
| 831 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); | |
| 832 goto err; | |
| 833 } | |
| 834 | |
| 835 var = points; | |
| 836 var[num] = NULL; /* pivot */ | |
| 837 for (i = 0; i < num; i++) | |
| 838 { | |
| 839 if ((var[i] = EC_POINT_new(group)) == NULL) | |
| 840 { | |
| 841 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE
); | |
| 842 goto err; | |
| 843 } | |
| 844 } | |
| 845 | |
| 846 if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) | |
| 847 { | |
| 848 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); | |
| 849 goto err; | |
| 850 } | |
| 851 | |
| 852 if (!EC_POINT_copy(base, generator)) | |
| 853 goto err; | |
| 854 | |
| 855 /* do the precomputation */ | |
| 856 for (i = 0; i < numblocks; i++) | |
| 857 { | |
| 858 size_t j; | |
| 859 | |
| 860 if (!EC_POINT_dbl(group, tmp_point, base, ctx)) | |
| 861 goto err; | |
| 862 | |
| 863 if (!EC_POINT_copy(*var++, base)) | |
| 864 goto err; | |
| 865 | |
| 866 for (j = 1; j < pre_points_per_block; j++, var++) | |
| 867 { | |
| 868 /* calculate odd multiples of the current base point */ | |
| 869 if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ct
x)) | |
| 870 goto err; | |
| 871 } | |
| 872 | |
| 873 if (i < numblocks - 1) | |
| 874 { | |
| 875 /* get the next base (multiply current one by 2^blocksiz
e) */ | |
| 876 size_t k; | |
| 877 | |
| 878 if (blocksize <= 2) | |
| 879 { | |
| 880 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERN
AL_ERROR); | |
| 881 goto err; | |
| 882 } | |
| 883 | |
| 884 if (!EC_POINT_dbl(group, base, tmp_point, ctx)) | |
| 885 goto err; | |
| 886 for (k = 2; k < blocksize; k++) | |
| 887 { | |
| 888 if (!EC_POINT_dbl(group,base,base,ctx)) | |
| 889 goto err; | |
| 890 } | |
| 891 } | |
| 892 } | |
| 893 | |
| 894 if (!EC_POINTs_make_affine(group, num, points, ctx)) | |
| 895 goto err; | |
| 896 | |
| 897 pre_comp->group = group; | |
| 898 pre_comp->blocksize = blocksize; | |
| 899 pre_comp->numblocks = numblocks; | |
| 900 pre_comp->w = w; | |
| 901 pre_comp->points = points; | |
| 902 points = NULL; | |
| 903 pre_comp->num = num; | |
| 904 | |
| 905 if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp, | |
| 906 ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free)) | |
| 907 goto err; | |
| 908 pre_comp = NULL; | |
| 909 | |
| 910 ret = 1; | |
| 911 err: | |
| 912 if (ctx != NULL) | |
| 913 BN_CTX_end(ctx); | |
| 914 if (new_ctx != NULL) | |
| 915 BN_CTX_free(new_ctx); | |
| 916 if (pre_comp) | |
| 917 ec_pre_comp_free(pre_comp); | |
| 918 if (points) | |
| 919 { | |
| 920 EC_POINT **p; | |
| 921 | |
| 922 for (p = points; *p != NULL; p++) | |
| 923 EC_POINT_free(*p); | |
| 924 OPENSSL_free(points); | |
| 925 } | |
| 926 if (tmp_point) | |
| 927 EC_POINT_free(tmp_point); | |
| 928 if (base) | |
| 929 EC_POINT_free(base); | |
| 930 return ret; | |
| 931 } | |
| 932 | |
| 933 | |
| 934 int ec_wNAF_have_precompute_mult(const EC_GROUP *group) | |
| 935 { | |
| 936 if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_
free, ec_pre_comp_clear_free) != NULL) | |
| 937 return 1; | |
| 938 else | |
| 939 return 0; | |
| 940 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 2072073002:
Delete bundled copy of OpenSSL and replace with README. (Closed)
Base URL: https://chromium.googlesource.com/chromium/deps/openssl@master