Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1 | /* Originally written by Bodo Moeller for the OpenSSL project. |
| 2 | * ==================================================================== |
| 3 | * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in |
| 14 | * the documentation and/or other materials provided with the |
| 15 | * distribution. |
| 16 | * |
| 17 | * 3. All advertising materials mentioning features or use of this |
| 18 | * software must display the following acknowledgment: |
| 19 | * "This product includes software developed by the OpenSSL Project |
| 20 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
| 21 | * |
| 22 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| 23 | * endorse or promote products derived from this software without |
| 24 | * prior written permission. For written permission, please contact |
| 25 | * openssl-core@openssl.org. |
| 26 | * |
| 27 | * 5. Products derived from this software may not be called "OpenSSL" |
| 28 | * nor may "OpenSSL" appear in their names without prior written |
| 29 | * permission of the OpenSSL Project. |
| 30 | * |
| 31 | * 6. Redistributions of any form whatsoever must retain the following |
| 32 | * acknowledgment: |
| 33 | * "This product includes software developed by the OpenSSL Project |
| 34 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
| 35 | * |
| 36 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| 37 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 38 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 39 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| 40 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 41 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 42 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| 43 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 44 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 45 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 46 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| 47 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| 48 | * ==================================================================== |
| 49 | * |
| 50 | * This product includes cryptographic software written by Eric Young |
| 51 | * (eay@cryptsoft.com). This product includes software written by Tim |
| 52 | * Hudson (tjh@cryptsoft.com). |
| 53 | * |
| 54 | */ |
| 55 | /* ==================================================================== |
| 56 | * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. |
| 57 | * |
| 58 | * Portions of the attached software ("Contribution") are developed by |
| 59 | * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project. |
| 60 | * |
| 61 | * The Contribution is licensed pursuant to the OpenSSL open source |
| 62 | * license provided above. |
| 63 | * |
| 64 | * The elliptic curve binary polynomial software is originally written by |
| 65 | * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems |
| 66 | * Laboratories. */ |
| 67 | |
| 68 | #include <openssl/ec.h> |
| 69 | |
| 70 | #include <string.h> |
| 71 | |
| 72 | #include <openssl/bn.h> |
| 73 | #include <openssl/err.h> |
| 74 | #include <openssl/mem.h> |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 75 | #include <openssl/thread.h> |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 76 | |
| 77 | #include "internal.h" |
| 78 | |
| 79 | |
| 80 | /* This file implements the wNAF-based interleaving multi-exponentation method |
| 81 | * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>); |
| 82 | * for multiplication with precomputation, we use wNAF splitting |
| 83 | * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>). |
| 84 | * */ |
| 85 | |
| 86 | /* structure for precomputed multiples of the generator */ |
| 87 | typedef struct ec_pre_comp_st { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 88 | size_t blocksize; /* block size for wNAF splitting */ |
| 89 | size_t numblocks; /* max. number of blocks for which we have precomputation */ |
| 90 | size_t w; /* window size */ |
| 91 | EC_POINT **points; /* array with pre-calculated multiples of generator: |
| 92 | * 'num' pointers to EC_POINT objects followed by a NULL */ |
| 93 | size_t num; /* numblocks * 2^(w-1) */ |
| 94 | int references; |
| 95 | } EC_PRE_COMP; |
| 96 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 97 | static EC_PRE_COMP *ec_pre_comp_new(void) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 98 | EC_PRE_COMP *ret = NULL; |
| 99 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 100 | ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); |
| 101 | if (!ret) { |
| 102 | OPENSSL_PUT_ERROR(EC, ec_pre_comp_new, ERR_R_MALLOC_FAILURE); |
| 103 | return ret; |
| 104 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 105 | ret->blocksize = 8; /* default */ |
| 106 | ret->numblocks = 0; |
| 107 | ret->w = 4; /* default */ |
| 108 | ret->points = NULL; |
| 109 | ret->num = 0; |
| 110 | ret->references = 1; |
| 111 | return ret; |
| 112 | } |
| 113 | |
| 114 | void *ec_pre_comp_dup(EC_PRE_COMP *pre_comp) { |
| 115 | if (pre_comp == NULL) { |
| 116 | return NULL; |
| 117 | } |
| 118 | |
| 119 | CRYPTO_add(&pre_comp->references, 1, CRYPTO_LOCK_EC_PRE_COMP); |
| 120 | return pre_comp; |
| 121 | } |
| 122 | |
| 123 | void ec_pre_comp_free(EC_PRE_COMP *pre_comp) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 124 | if (pre_comp == NULL || |
| 125 | CRYPTO_add(&pre_comp->references, -1, CRYPTO_LOCK_EC_PRE_COMP) > 0) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 126 | return; |
| 127 | } |
| 128 | |
| 129 | if (pre_comp->points) { |
| 130 | EC_POINT **p; |
| 131 | |
| 132 | for (p = pre_comp->points; *p != NULL; p++) { |
| 133 | EC_POINT_free(*p); |
| 134 | } |
| 135 | OPENSSL_free(pre_comp->points); |
| 136 | } |
| 137 | OPENSSL_free(pre_comp); |
| 138 | } |
| 139 | |
| 140 | |
| 141 | /* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. |
| 142 | * This is an array r[] of values that are either zero or odd with an |
| 143 | * absolute value less than 2^w satisfying |
| 144 | * scalar = \sum_j r[j]*2^j |
| 145 | * where at most one of any w+1 consecutive digits is non-zero |
| 146 | * with the exception that the most significant digit may be only |
| 147 | * w-1 zeros away from that next non-zero digit. |
| 148 | */ |
| 149 | static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len) { |
| 150 | int window_val; |
| 151 | int ok = 0; |
| 152 | signed char *r = NULL; |
| 153 | int sign = 1; |
| 154 | int bit, next_bit, mask; |
| 155 | size_t len = 0, j; |
| 156 | |
| 157 | if (BN_is_zero(scalar)) { |
| 158 | r = OPENSSL_malloc(1); |
| 159 | if (!r) { |
| 160 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_MALLOC_FAILURE); |
| 161 | goto err; |
| 162 | } |
| 163 | r[0] = 0; |
| 164 | *ret_len = 1; |
| 165 | return r; |
| 166 | } |
| 167 | |
| 168 | if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute |
| 169 | values less than 2^7 */ |
| 170 | { |
| 171 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 172 | goto err; |
| 173 | } |
| 174 | bit = 1 << w; /* at most 128 */ |
| 175 | next_bit = bit << 1; /* at most 256 */ |
| 176 | mask = next_bit - 1; /* at most 255 */ |
| 177 | |
| 178 | if (BN_is_negative(scalar)) { |
| 179 | sign = -1; |
| 180 | } |
| 181 | |
| 182 | if (scalar->d == NULL || scalar->top == 0) { |
| 183 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 184 | goto err; |
| 185 | } |
| 186 | |
| 187 | len = BN_num_bits(scalar); |
| 188 | r = OPENSSL_malloc( |
| 189 | len + |
| 190 | 1); /* modified wNAF may be one digit longer than binary representation |
| 191 | * (*ret_len will be set to the actual length, i.e. at most |
| 192 | * BN_num_bits(scalar) + 1) */ |
| 193 | if (r == NULL) { |
| 194 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_MALLOC_FAILURE); |
| 195 | goto err; |
| 196 | } |
| 197 | window_val = scalar->d[0] & mask; |
| 198 | j = 0; |
| 199 | while ((window_val != 0) || |
| 200 | (j + w + 1 < len)) /* if j+w+1 >= len, window_val will not increase */ |
| 201 | { |
| 202 | int digit = 0; |
| 203 | |
| 204 | /* 0 <= window_val <= 2^(w+1) */ |
| 205 | |
| 206 | if (window_val & 1) { |
| 207 | /* 0 < window_val < 2^(w+1) */ |
| 208 | |
| 209 | if (window_val & bit) { |
| 210 | digit = window_val - next_bit; /* -2^w < digit < 0 */ |
| 211 | |
| 212 | #if 1 /* modified wNAF */ |
| 213 | if (j + w + 1 >= len) { |
| 214 | /* special case for generating modified wNAFs: |
| 215 | * no new bits will be added into window_val, |
| 216 | * so using a positive digit here will decrease |
| 217 | * the total length of the representation */ |
| 218 | |
| 219 | digit = window_val & (mask >> 1); /* 0 < digit < 2^w */ |
| 220 | } |
| 221 | #endif |
| 222 | } else { |
| 223 | digit = window_val; /* 0 < digit < 2^w */ |
| 224 | } |
| 225 | |
| 226 | if (digit <= -bit || digit >= bit || !(digit & 1)) { |
| 227 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 228 | goto err; |
| 229 | } |
| 230 | |
| 231 | window_val -= digit; |
| 232 | |
| 233 | /* now window_val is 0 or 2^(w+1) in standard wNAF generation; |
| 234 | * for modified window NAFs, it may also be 2^w |
| 235 | */ |
| 236 | if (window_val != 0 && window_val != next_bit && window_val != bit) { |
| 237 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 238 | goto err; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | r[j++] = sign * digit; |
| 243 | |
| 244 | window_val >>= 1; |
| 245 | window_val += bit * BN_is_bit_set(scalar, j + w); |
| 246 | |
| 247 | if (window_val > next_bit) { |
| 248 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 249 | goto err; |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | if (j > len + 1) { |
| 254 | OPENSSL_PUT_ERROR(EC, compute_wNAF, ERR_R_INTERNAL_ERROR); |
| 255 | goto err; |
| 256 | } |
| 257 | len = j; |
| 258 | ok = 1; |
| 259 | |
| 260 | err: |
| 261 | if (!ok) { |
| 262 | OPENSSL_free(r); |
| 263 | r = NULL; |
| 264 | } |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 265 | if (ok) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 266 | *ret_len = len; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 267 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 268 | return r; |
| 269 | } |
| 270 | |
| 271 | |
| 272 | /* TODO: table should be optimised for the wNAF-based implementation, |
| 273 | * sometimes smaller windows will give better performance |
| 274 | * (thus the boundaries should be increased) |
| 275 | */ |
| 276 | #define EC_window_bits_for_scalar_size(b) \ |
| 277 | ((size_t)((b) >= 2000 ? 6 : (b) >= 800 ? 5 : (b) >= 300 \ |
| 278 | ? 4 \ |
| 279 | : (b) >= 70 ? 3 : (b) >= 20 \ |
| 280 | ? 2 \ |
| 281 | : 1)) |
| 282 | |
| 283 | /* Compute |
| 284 | * \sum scalars[i]*points[i], |
| 285 | * also including |
| 286 | * scalar*generator |
| 287 | * in the addition if scalar != NULL |
| 288 | */ |
| 289 | int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, |
| 290 | size_t num, const EC_POINT *points[], const BIGNUM *scalars[], |
| 291 | BN_CTX *ctx) { |
| 292 | BN_CTX *new_ctx = NULL; |
| 293 | const EC_POINT *generator = NULL; |
| 294 | EC_POINT *tmp = NULL; |
| 295 | size_t totalnum; |
| 296 | size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */ |
| 297 | size_t pre_points_per_block = 0; |
| 298 | size_t i, j; |
| 299 | int k; |
| 300 | int r_is_inverted = 0; |
| 301 | int r_is_at_infinity = 1; |
| 302 | size_t *wsize = NULL; /* individual window sizes */ |
| 303 | signed char **wNAF = NULL; /* individual wNAFs */ |
| 304 | size_t *wNAF_len = NULL; |
| 305 | size_t max_len = 0; |
| 306 | size_t num_val; |
| 307 | EC_POINT **val = NULL; /* precomputation */ |
| 308 | EC_POINT **v; |
| 309 | EC_POINT ***val_sub = |
| 310 | NULL; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */ |
| 311 | const EC_PRE_COMP *pre_comp = NULL; |
| 312 | int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treated like |
| 313 | * other scalars, |
| 314 | * i.e. precomputation is not available */ |
| 315 | int ret = 0; |
| 316 | |
| 317 | if (group->meth != r->meth) { |
| 318 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, EC_R_INCOMPATIBLE_OBJECTS); |
| 319 | return 0; |
| 320 | } |
| 321 | |
| 322 | if ((scalar == NULL) && (num == 0)) { |
| 323 | return EC_POINT_set_to_infinity(group, r); |
| 324 | } |
| 325 | |
| 326 | for (i = 0; i < num; i++) { |
| 327 | if (group->meth != points[i]->meth) { |
| 328 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, EC_R_INCOMPATIBLE_OBJECTS); |
| 329 | return 0; |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | if (ctx == NULL) { |
| 334 | ctx = new_ctx = BN_CTX_new(); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 335 | if (ctx == NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 336 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 337 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 338 | } |
| 339 | |
| 340 | if (scalar != NULL) { |
| 341 | generator = EC_GROUP_get0_generator(group); |
| 342 | if (generator == NULL) { |
| 343 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, EC_R_UNDEFINED_GENERATOR); |
| 344 | goto err; |
| 345 | } |
| 346 | |
| 347 | /* look if we can use precomputed multiples of generator */ |
| 348 | |
| 349 | pre_comp = group->pre_comp; |
| 350 | |
| 351 | if (pre_comp && pre_comp->numblocks && |
| 352 | (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0)) { |
| 353 | blocksize = pre_comp->blocksize; |
| 354 | |
| 355 | /* determine maximum number of blocks that wNAF splitting may yield |
| 356 | * (NB: maximum wNAF length is bit length plus one) */ |
| 357 | numblocks = (BN_num_bits(scalar) / blocksize) + 1; |
| 358 | |
| 359 | /* we cannot use more blocks than we have precomputation for */ |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 360 | if (numblocks > pre_comp->numblocks) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 361 | numblocks = pre_comp->numblocks; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 362 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 363 | |
| 364 | pre_points_per_block = (size_t)1 << (pre_comp->w - 1); |
| 365 | |
| 366 | /* check that pre_comp looks sane */ |
| 367 | if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) { |
| 368 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 369 | goto err; |
| 370 | } |
| 371 | } else { |
| 372 | /* can't use precomputation */ |
| 373 | pre_comp = NULL; |
| 374 | numblocks = 1; |
| 375 | num_scalar = 1; /* treat 'scalar' like 'num'-th element of 'scalars' */ |
| 376 | } |
| 377 | } |
| 378 | |
| 379 | totalnum = num + numblocks; |
| 380 | |
| 381 | wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); |
| 382 | wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); |
| 383 | wNAF = OPENSSL_malloc((totalnum + 1) * |
| 384 | sizeof wNAF[0]); /* includes space for pivot */ |
| 385 | val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); |
| 386 | |
| 387 | /* Ensure wNAF is initialised in case we end up going to err. */ |
| 388 | if (wNAF) { |
| 389 | wNAF[0] = NULL; /* preliminary pivot */ |
| 390 | } |
| 391 | |
| 392 | if (!wsize || !wNAF_len || !wNAF || !val_sub) { |
| 393 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_MALLOC_FAILURE); |
| 394 | goto err; |
| 395 | } |
| 396 | |
| 397 | /* num_val will be the total number of temporarily precomputed points */ |
| 398 | num_val = 0; |
| 399 | |
| 400 | for (i = 0; i < num + num_scalar; i++) { |
| 401 | size_t bits; |
| 402 | |
| 403 | bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); |
| 404 | wsize[i] = EC_window_bits_for_scalar_size(bits); |
| 405 | num_val += (size_t)1 << (wsize[i] - 1); |
| 406 | wNAF[i + 1] = NULL; /* make sure we always have a pivot */ |
| 407 | wNAF[i] = |
| 408 | compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 409 | if (wNAF[i] == NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 410 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 411 | } |
| 412 | if (wNAF_len[i] > max_len) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 413 | max_len = wNAF_len[i]; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 414 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 415 | } |
| 416 | |
| 417 | if (numblocks) { |
| 418 | /* we go here iff scalar != NULL */ |
| 419 | |
| 420 | if (pre_comp == NULL) { |
| 421 | if (num_scalar != 1) { |
| 422 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 423 | goto err; |
| 424 | } |
| 425 | /* we have already generated a wNAF for 'scalar' */ |
| 426 | } else { |
| 427 | signed char *tmp_wNAF = NULL; |
| 428 | size_t tmp_len = 0; |
| 429 | |
| 430 | if (num_scalar != 0) { |
| 431 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 432 | goto err; |
| 433 | } |
| 434 | |
| 435 | /* use the window size for which we have precomputation */ |
| 436 | wsize[num] = pre_comp->w; |
| 437 | tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 438 | if (!tmp_wNAF) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 439 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 440 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 441 | |
| 442 | if (tmp_len <= max_len) { |
| 443 | /* One of the other wNAFs is at least as long |
| 444 | * as the wNAF belonging to the generator, |
| 445 | * so wNAF splitting will not buy us anything. */ |
| 446 | |
| 447 | numblocks = 1; /* don't use wNAF splitting */ |
| 448 | totalnum = num + numblocks; |
| 449 | wNAF[num] = tmp_wNAF; |
| 450 | wNAF[num + 1] = NULL; |
| 451 | wNAF_len[num] = tmp_len; |
| 452 | /* pre_comp->points starts with the points that we need here: */ |
| 453 | val_sub[num] = pre_comp->points; |
| 454 | } else { |
| 455 | /* don't include tmp_wNAF directly into wNAF array |
| 456 | * - use wNAF splitting and include the blocks */ |
| 457 | |
| 458 | signed char *pp; |
| 459 | EC_POINT **tmp_points; |
| 460 | |
| 461 | if (tmp_len < numblocks * blocksize) { |
| 462 | /* possibly we can do with fewer blocks than estimated */ |
| 463 | numblocks = (tmp_len + blocksize - 1) / blocksize; |
| 464 | if (numblocks > pre_comp->numblocks) { |
| 465 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 466 | goto err; |
| 467 | } |
| 468 | totalnum = num + numblocks; |
| 469 | } |
| 470 | |
| 471 | /* split wNAF in 'numblocks' parts */ |
| 472 | pp = tmp_wNAF; |
| 473 | tmp_points = pre_comp->points; |
| 474 | |
| 475 | for (i = num; i < totalnum; i++) { |
| 476 | if (i < totalnum - 1) { |
| 477 | wNAF_len[i] = blocksize; |
| 478 | if (tmp_len < blocksize) { |
| 479 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 480 | goto err; |
| 481 | } |
| 482 | tmp_len -= blocksize; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 483 | } else { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 484 | /* last block gets whatever is left |
| 485 | * (this could be more or less than 'blocksize'!) */ |
| 486 | wNAF_len[i] = tmp_len; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 487 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 488 | |
| 489 | wNAF[i + 1] = NULL; |
| 490 | wNAF[i] = OPENSSL_malloc(wNAF_len[i]); |
| 491 | if (wNAF[i] == NULL) { |
| 492 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_MALLOC_FAILURE); |
| 493 | OPENSSL_free(tmp_wNAF); |
| 494 | goto err; |
| 495 | } |
| 496 | memcpy(wNAF[i], pp, wNAF_len[i]); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 497 | if (wNAF_len[i] > max_len) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 498 | max_len = wNAF_len[i]; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 499 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 500 | |
| 501 | if (*tmp_points == NULL) { |
| 502 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 503 | OPENSSL_free(tmp_wNAF); |
| 504 | goto err; |
| 505 | } |
| 506 | val_sub[i] = tmp_points; |
| 507 | tmp_points += pre_points_per_block; |
| 508 | pp += blocksize; |
| 509 | } |
| 510 | OPENSSL_free(tmp_wNAF); |
| 511 | } |
| 512 | } |
| 513 | } |
| 514 | |
| 515 | /* All points we precompute now go into a single array 'val'. |
| 516 | * 'val_sub[i]' is a pointer to the subarray for the i-th point, |
| 517 | * or to a subarray of 'pre_comp->points' if we already have precomputation. |
| 518 | */ |
| 519 | val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); |
| 520 | if (val == NULL) { |
| 521 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_MALLOC_FAILURE); |
| 522 | goto err; |
| 523 | } |
| 524 | val[num_val] = NULL; /* pivot element */ |
| 525 | |
| 526 | /* allocate points for precomputation */ |
| 527 | v = val; |
| 528 | for (i = 0; i < num + num_scalar; i++) { |
| 529 | val_sub[i] = v; |
| 530 | for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) { |
| 531 | *v = EC_POINT_new(group); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 532 | if (*v == NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 533 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 534 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 535 | v++; |
| 536 | } |
| 537 | } |
| 538 | if (!(v == val + num_val)) { |
| 539 | OPENSSL_PUT_ERROR(EC, ec_wNAF_mul, ERR_R_INTERNAL_ERROR); |
| 540 | goto err; |
| 541 | } |
| 542 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 543 | if (!(tmp = EC_POINT_new(group))) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 544 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 545 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 546 | |
| 547 | /* prepare precomputed values: |
| 548 | * val_sub[i][0] := points[i] |
| 549 | * val_sub[i][1] := 3 * points[i] |
| 550 | * val_sub[i][2] := 5 * points[i] |
| 551 | * ... |
| 552 | */ |
| 553 | for (i = 0; i < num + num_scalar; i++) { |
| 554 | if (i < num) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 555 | if (!EC_POINT_copy(val_sub[i][0], points[i])) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 556 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 557 | } |
| 558 | } else if (!EC_POINT_copy(val_sub[i][0], generator)) { |
| 559 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 560 | } |
| 561 | |
| 562 | if (wsize[i] > 1) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 563 | if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 564 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 565 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 566 | for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 567 | if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 568 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 569 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 570 | } |
| 571 | } |
| 572 | } |
| 573 | |
| 574 | #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 575 | if (!EC_POINTs_make_affine(group, num_val, val, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 576 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 577 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 578 | #endif |
| 579 | |
| 580 | r_is_at_infinity = 1; |
| 581 | |
| 582 | for (k = max_len - 1; k >= 0; k--) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 583 | if (!r_is_at_infinity && !EC_POINT_dbl(group, r, r, ctx)) { |
| 584 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 585 | } |
| 586 | |
| 587 | for (i = 0; i < totalnum; i++) { |
| 588 | if (wNAF_len[i] > (size_t)k) { |
| 589 | int digit = wNAF[i][k]; |
| 590 | int is_neg; |
| 591 | |
| 592 | if (digit) { |
| 593 | is_neg = digit < 0; |
| 594 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 595 | if (is_neg) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 596 | digit = -digit; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 597 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 598 | |
| 599 | if (is_neg != r_is_inverted) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 600 | if (!r_is_at_infinity && !EC_POINT_invert(group, r, ctx)) { |
| 601 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 602 | } |
| 603 | r_is_inverted = !r_is_inverted; |
| 604 | } |
| 605 | |
| 606 | /* digit > 0 */ |
| 607 | |
| 608 | if (r_is_at_infinity) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 609 | if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 610 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 611 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 612 | r_is_at_infinity = 0; |
| 613 | } else { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 614 | if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 615 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 616 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 617 | } |
| 618 | } |
| 619 | } |
| 620 | } |
| 621 | } |
| 622 | |
| 623 | if (r_is_at_infinity) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 624 | if (!EC_POINT_set_to_infinity(group, r)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 625 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 626 | } |
| 627 | } else if (r_is_inverted && !EC_POINT_invert(group, r, ctx)) { |
| 628 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 629 | } |
| 630 | |
| 631 | ret = 1; |
| 632 | |
| 633 | err: |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 634 | BN_CTX_free(new_ctx); |
| 635 | EC_POINT_free(tmp); |
| 636 | OPENSSL_free(wsize); |
| 637 | OPENSSL_free(wNAF_len); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 638 | if (wNAF != NULL) { |
| 639 | signed char **w; |
| 640 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 641 | for (w = wNAF; *w != NULL; w++) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 642 | OPENSSL_free(*w); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 643 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 644 | |
| 645 | OPENSSL_free(wNAF); |
| 646 | } |
| 647 | if (val != NULL) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 648 | for (v = val; *v != NULL; v++) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 649 | EC_POINT_clear_free(*v); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 650 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 651 | |
| 652 | OPENSSL_free(val); |
| 653 | } |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 654 | OPENSSL_free(val_sub); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 655 | return ret; |
| 656 | } |
| 657 | |
| 658 | |
| 659 | /* ec_wNAF_precompute_mult() |
| 660 | * creates an EC_PRE_COMP object with preprecomputed multiples of the generator |
| 661 | * for use with wNAF splitting as implemented in ec_wNAF_mul(). |
| 662 | * |
| 663 | * 'pre_comp->points' is an array of multiples of the generator |
| 664 | * of the following form: |
| 665 | * points[0] = generator; |
| 666 | * points[1] = 3 * generator; |
| 667 | * ... |
| 668 | * points[2^(w-1)-1] = (2^(w-1)-1) * generator; |
| 669 | * points[2^(w-1)] = 2^blocksize * generator; |
| 670 | * points[2^(w-1)+1] = 3 * 2^blocksize * generator; |
| 671 | * ... |
| 672 | * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) * |
| 673 | *generator |
| 674 | * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) * |
| 675 | *generator |
| 676 | * ... |
| 677 | * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) * |
| 678 | *generator |
| 679 | * points[2^(w-1)*numblocks] = NULL |
| 680 | */ |
| 681 | int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx) { |
| 682 | const EC_POINT *generator; |
| 683 | EC_POINT *tmp_point = NULL, *base = NULL, **var; |
| 684 | BN_CTX *new_ctx = NULL; |
| 685 | BIGNUM *order; |
| 686 | size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num; |
| 687 | EC_POINT **points = NULL; |
| 688 | EC_PRE_COMP *pre_comp; |
| 689 | int ret = 0; |
| 690 | |
| 691 | /* if there is an old EC_PRE_COMP object, throw it away */ |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 692 | ec_pre_comp_free(group->pre_comp); |
| 693 | group->pre_comp = NULL; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 694 | |
| 695 | generator = EC_GROUP_get0_generator(group); |
| 696 | if (generator == NULL) { |
| 697 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, EC_R_UNDEFINED_GENERATOR); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 698 | return 0; |
| 699 | } |
| 700 | |
| 701 | pre_comp = ec_pre_comp_new(); |
| 702 | if (pre_comp == NULL) { |
| 703 | return 0; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 704 | } |
| 705 | |
| 706 | if (ctx == NULL) { |
| 707 | ctx = new_ctx = BN_CTX_new(); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 708 | if (ctx == NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 709 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 710 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 711 | } |
| 712 | |
| 713 | BN_CTX_start(ctx); |
| 714 | order = BN_CTX_get(ctx); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 715 | if (order == NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 716 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 717 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 718 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 719 | if (!EC_GROUP_get_order(group, order, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 720 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 721 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 722 | if (BN_is_zero(order)) { |
| 723 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, EC_R_UNKNOWN_ORDER); |
| 724 | goto err; |
| 725 | } |
| 726 | |
| 727 | bits = BN_num_bits(order); |
| 728 | /* The following parameters mean we precompute (approximately) |
| 729 | * one point per bit. |
| 730 | * |
| 731 | * TBD: The combination 8, 4 is perfect for 160 bits; for other |
| 732 | * bit lengths, other parameter combinations might provide better |
| 733 | * efficiency. |
| 734 | */ |
| 735 | blocksize = 8; |
| 736 | w = 4; |
| 737 | if (EC_window_bits_for_scalar_size(bits) > w) { |
| 738 | /* let's not make the window too small ... */ |
| 739 | w = EC_window_bits_for_scalar_size(bits); |
| 740 | } |
| 741 | |
| 742 | numblocks = (bits + blocksize - 1) / |
| 743 | blocksize; /* max. number of blocks to use for wNAF splitting */ |
| 744 | |
| 745 | pre_points_per_block = (size_t)1 << (w - 1); |
| 746 | num = pre_points_per_block * |
| 747 | numblocks; /* number of points to compute and store */ |
| 748 | |
| 749 | points = OPENSSL_malloc(sizeof(EC_POINT *) * (num + 1)); |
| 750 | if (!points) { |
| 751 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, ERR_R_MALLOC_FAILURE); |
| 752 | goto err; |
| 753 | } |
| 754 | |
| 755 | var = points; |
| 756 | var[num] = NULL; /* pivot */ |
| 757 | for (i = 0; i < num; i++) { |
| 758 | if ((var[i] = EC_POINT_new(group)) == NULL) { |
| 759 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, ERR_R_MALLOC_FAILURE); |
| 760 | goto err; |
| 761 | } |
| 762 | } |
| 763 | |
| 764 | if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) { |
| 765 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, ERR_R_MALLOC_FAILURE); |
| 766 | goto err; |
| 767 | } |
| 768 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 769 | if (!EC_POINT_copy(base, generator)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 770 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 771 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 772 | |
| 773 | /* do the precomputation */ |
| 774 | for (i = 0; i < numblocks; i++) { |
| 775 | size_t j; |
| 776 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 777 | if (!EC_POINT_dbl(group, tmp_point, base, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 778 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 779 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 780 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 781 | if (!EC_POINT_copy(*var++, base)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 782 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 783 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 784 | |
| 785 | for (j = 1; j < pre_points_per_block; j++, var++) { |
| 786 | /* calculate odd multiples of the current base point */ |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 787 | if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 788 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 789 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 790 | } |
| 791 | |
| 792 | if (i < numblocks - 1) { |
| 793 | /* get the next base (multiply current one by 2^blocksize) */ |
| 794 | size_t k; |
| 795 | |
| 796 | if (blocksize <= 2) { |
| 797 | OPENSSL_PUT_ERROR(EC, ec_wNAF_precompute_mult, ERR_R_INTERNAL_ERROR); |
| 798 | goto err; |
| 799 | } |
| 800 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 801 | if (!EC_POINT_dbl(group, base, tmp_point, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 802 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 803 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 804 | for (k = 2; k < blocksize; k++) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 805 | if (!EC_POINT_dbl(group, base, base, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 806 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 807 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 808 | } |
| 809 | } |
| 810 | } |
| 811 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 812 | if (!EC_POINTs_make_affine(group, num, points, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 813 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 814 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 815 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 816 | pre_comp->blocksize = blocksize; |
| 817 | pre_comp->numblocks = numblocks; |
| 818 | pre_comp->w = w; |
| 819 | pre_comp->points = points; |
| 820 | points = NULL; |
| 821 | pre_comp->num = num; |
| 822 | |
| 823 | group->pre_comp = pre_comp; |
| 824 | pre_comp = NULL; |
| 825 | |
| 826 | ret = 1; |
| 827 | |
| 828 | err: |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 829 | if (ctx != NULL) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 830 | BN_CTX_end(ctx); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 831 | } |
| 832 | BN_CTX_free(new_ctx); |
| 833 | ec_pre_comp_free(pre_comp); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 834 | if (points) { |
| 835 | EC_POINT **p; |
| 836 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 837 | for (p = points; *p != NULL; p++) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 838 | EC_POINT_free(*p); |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 839 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 840 | OPENSSL_free(points); |
| 841 | } |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame^] | 842 | EC_POINT_free(tmp_point); |
| 843 | EC_POINT_free(base); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 844 | return ret; |
| 845 | } |
| 846 | |
| 847 | |
| 848 | int ec_wNAF_have_precompute_mult(const EC_GROUP *group) { |
| 849 | return group->pre_comp != NULL; |
| 850 | } |