]>
Commit | Line | Data |
---|---|---|
65e81670 | 1 | /* crypto/ec/ec_mult.c */ |
35b73a1f | 2 | /* |
37c660ff | 3 | * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project. |
35b73a1f | 4 | */ |
65e81670 | 5 | /* ==================================================================== |
19f6c524 | 6 | * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. |
65e81670 BM |
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 | */ | |
7793f30e BM |
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 | */ | |
65e81670 | 63 | |
73e45b2d | 64 | |
84b08eee | 65 | |
28f573a2 | 66 | #include <string.h> |
48fe4d62 BM |
67 | #include <openssl/err.h> |
68 | ||
5784a521 | 69 | #include "internal/bn_int.h" |
65e81670 | 70 | #include "ec_lcl.h" |
48fe4d62 BM |
71 | |
72 | ||
37c660ff BM |
73 | /* |
74 | * This file implements the wNAF-based interleaving multi-exponentation method | |
75 | * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>); | |
76 | * for multiplication with precomputation, we use wNAF splitting | |
77 | * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>). | |
78 | */ | |
48fe4d62 BM |
79 | |
80 | ||
f916052e | 81 | |
37c660ff BM |
82 | |
83 | /* structure for precomputed multiples of the generator */ | |
84 | typedef struct ec_pre_comp_st { | |
85 | const EC_GROUP *group; /* parent EC_GROUP object */ | |
86 | size_t blocksize; /* block size for wNAF splitting */ | |
87 | size_t numblocks; /* max. number of blocks for which we have precomputation */ | |
88 | size_t w; /* window size */ | |
89 | EC_POINT **points; /* array with pre-calculated multiples of generator: | |
90 | * 'num' pointers to EC_POINT objects followed by a NULL */ | |
91 | size_t num; /* numblocks * 2^(w-1) */ | |
ba729265 | 92 | int references; |
37c660ff BM |
93 | } EC_PRE_COMP; |
94 | ||
95 | /* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */ | |
96 | static void *ec_pre_comp_dup(void *); | |
97 | static void ec_pre_comp_free(void *); | |
98 | static void ec_pre_comp_clear_free(void *); | |
99 | ||
100 | static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group) | |
101 | { | |
102 | EC_PRE_COMP *ret = NULL; | |
103 | ||
104 | if (!group) | |
105 | return NULL; | |
106 | ||
107 | ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); | |
108 | if (!ret) | |
19f6c524 BM |
109 | { |
110 | ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE); | |
37c660ff | 111 | return ret; |
19f6c524 | 112 | } |
37c660ff BM |
113 | ret->group = group; |
114 | ret->blocksize = 8; /* default */ | |
115 | ret->numblocks = 0; | |
116 | ret->w = 4; /* default */ | |
117 | ret->points = NULL; | |
118 | ret->num = 0; | |
ba729265 | 119 | ret->references = 1; |
37c660ff BM |
120 | return ret; |
121 | } | |
122 | ||
123 | static void *ec_pre_comp_dup(void *src_) | |
124 | { | |
ba729265 | 125 | EC_PRE_COMP *src = src_; |
37c660ff | 126 | |
ba729265 | 127 | /* no need to actually copy, these objects never change! */ |
37c660ff | 128 | |
ba729265 | 129 | CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP); |
37c660ff | 130 | |
ba729265 | 131 | return src_; |
37c660ff BM |
132 | } |
133 | ||
134 | static void ec_pre_comp_free(void *pre_) | |
135 | { | |
ba729265 | 136 | int i; |
37c660ff BM |
137 | EC_PRE_COMP *pre = pre_; |
138 | ||
139 | if (!pre) | |
140 | return; | |
ba729265 BM |
141 | |
142 | i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); | |
143 | if (i > 0) | |
144 | return; | |
145 | ||
37c660ff BM |
146 | if (pre->points) |
147 | { | |
ba729265 | 148 | EC_POINT **p; |
37c660ff | 149 | |
ba729265 BM |
150 | for (p = pre->points; *p != NULL; p++) |
151 | EC_POINT_free(*p); | |
37c660ff BM |
152 | OPENSSL_free(pre->points); |
153 | } | |
154 | OPENSSL_free(pre); | |
155 | } | |
156 | ||
157 | static void ec_pre_comp_clear_free(void *pre_) | |
158 | { | |
ba729265 | 159 | int i; |
37c660ff BM |
160 | EC_PRE_COMP *pre = pre_; |
161 | ||
162 | if (!pre) | |
163 | return; | |
ba729265 BM |
164 | |
165 | i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); | |
166 | if (i > 0) | |
167 | return; | |
168 | ||
37c660ff BM |
169 | if (pre->points) |
170 | { | |
171 | EC_POINT **p; | |
172 | ||
173 | for (p = pre->points; *p != NULL; p++) | |
c94f7f65 | 174 | { |
37c660ff | 175 | EC_POINT_clear_free(*p); |
c94f7f65 BM |
176 | OPENSSL_cleanse(p, sizeof *p); |
177 | } | |
37c660ff BM |
178 | OPENSSL_free(pre->points); |
179 | } | |
c94f7f65 | 180 | OPENSSL_cleanse(pre, sizeof *pre); |
37c660ff BM |
181 | OPENSSL_free(pre); |
182 | } | |
183 | ||
184 | ||
3ba1f111 BM |
185 | |
186 | ||
3ba1f111 | 187 | |
3ba1f111 BM |
188 | |
189 | ||
c05940ed BM |
190 | /* TODO: table should be optimised for the wNAF-based implementation, |
191 | * sometimes smaller windows will give better performance | |
192 | * (thus the boundaries should be increased) | |
193 | */ | |
3ba1f111 | 194 | #define EC_window_bits_for_scalar_size(b) \ |
513c01a5 RL |
195 | ((size_t) \ |
196 | ((b) >= 2000 ? 6 : \ | |
197 | (b) >= 800 ? 5 : \ | |
198 | (b) >= 300 ? 4 : \ | |
199 | (b) >= 70 ? 3 : \ | |
200 | (b) >= 20 ? 2 : \ | |
201 | 1)) | |
3ba1f111 BM |
202 | |
203 | /* Compute | |
204 | * \sum scalars[i]*points[i], | |
205 | * also including | |
206 | * scalar*generator | |
207 | * in the addition if scalar != NULL | |
208 | */ | |
7793f30e | 209 | int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, |
3ba1f111 BM |
210 | size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx) |
211 | { | |
212 | BN_CTX *new_ctx = NULL; | |
9dd84053 | 213 | const EC_POINT *generator = NULL; |
3ba1f111 BM |
214 | EC_POINT *tmp = NULL; |
215 | size_t totalnum; | |
37c660ff BM |
216 | size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */ |
217 | size_t pre_points_per_block = 0; | |
3ba1f111 BM |
218 | size_t i, j; |
219 | int k; | |
220 | int r_is_inverted = 0; | |
221 | int r_is_at_infinity = 1; | |
222 | size_t *wsize = NULL; /* individual window sizes */ | |
c78515f5 | 223 | signed char **wNAF = NULL; /* individual wNAFs */ |
3ba1f111 BM |
224 | size_t *wNAF_len = NULL; |
225 | size_t max_len = 0; | |
3ba1f111 BM |
226 | size_t num_val; |
227 | EC_POINT **val = NULL; /* precomputation */ | |
228 | EC_POINT **v; | |
37c660ff | 229 | EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */ |
ba729265 | 230 | const EC_PRE_COMP *pre_comp = NULL; |
37c660ff BM |
231 | int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars, |
232 | * i.e. precomputation is not available */ | |
3ba1f111 BM |
233 | int ret = 0; |
234 | ||
37c660ff | 235 | if (group->meth != r->meth) |
3ba1f111 | 236 | { |
37c660ff BM |
237 | ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); |
238 | return 0; | |
3ba1f111 | 239 | } |
37c660ff BM |
240 | |
241 | if ((scalar == NULL) && (num == 0)) | |
242 | { | |
243 | return EC_POINT_set_to_infinity(group, r); | |
244 | } | |
245 | ||
3ba1f111 BM |
246 | for (i = 0; i < num; i++) |
247 | { | |
248 | if (group->meth != points[i]->meth) | |
249 | { | |
7793f30e | 250 | ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); |
3ba1f111 BM |
251 | return 0; |
252 | } | |
253 | } | |
254 | ||
37c660ff BM |
255 | if (ctx == NULL) |
256 | { | |
257 | ctx = new_ctx = BN_CTX_new(); | |
258 | if (ctx == NULL) | |
259 | goto err; | |
260 | } | |
3ba1f111 | 261 | |
37c660ff | 262 | if (scalar != NULL) |
3ba1f111 | 263 | { |
37c660ff BM |
264 | generator = EC_GROUP_get0_generator(group); |
265 | if (generator == NULL) | |
266 | { | |
267 | ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR); | |
268 | goto err; | |
269 | } | |
270 | ||
271 | /* look if we can use precomputed multiples of generator */ | |
272 | ||
9dd84053 | 273 | pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free); |
37c660ff BM |
274 | |
275 | if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0)) | |
276 | { | |
277 | blocksize = pre_comp->blocksize; | |
278 | ||
279 | /* determine maximum number of blocks that wNAF splitting may yield | |
280 | * (NB: maximum wNAF length is bit length plus one) */ | |
281 | numblocks = (BN_num_bits(scalar) / blocksize) + 1; | |
282 | ||
283 | /* we cannot use more blocks than we have precomputation for */ | |
284 | if (numblocks > pre_comp->numblocks) | |
285 | numblocks = pre_comp->numblocks; | |
286 | ||
194274cb | 287 | pre_points_per_block = (size_t)1 << (pre_comp->w - 1); |
37c660ff BM |
288 | |
289 | /* check that pre_comp looks sane */ | |
290 | if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) | |
291 | { | |
292 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
293 | goto err; | |
294 | } | |
295 | } | |
296 | else | |
297 | { | |
298 | /* can't use precomputation */ | |
299 | pre_comp = NULL; | |
300 | numblocks = 1; | |
301 | num_scalar = 1; /* treat 'scalar' like 'num'-th element of 'scalars' */ | |
302 | } | |
3ba1f111 | 303 | } |
37c660ff BM |
304 | |
305 | totalnum = num + numblocks; | |
306 | ||
307 | wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); | |
308 | wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); | |
309 | wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes space for pivot */ | |
310 | val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); | |
e04d426b MC |
311 | |
312 | /* Ensure wNAF is initialised in case we end up going to err */ | |
313 | if (wNAF) wNAF[0] = NULL; /* preliminary pivot */ | |
314 | ||
37c660ff | 315 | if (!wsize || !wNAF_len || !wNAF || !val_sub) |
19f6c524 BM |
316 | { |
317 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); | |
37c660ff | 318 | goto err; |
19f6c524 | 319 | } |
3ba1f111 | 320 | |
37c660ff | 321 | /* num_val will be the total number of temporarily precomputed points */ |
3ba1f111 | 322 | num_val = 0; |
37c660ff BM |
323 | |
324 | for (i = 0; i < num + num_scalar; i++) | |
3ba1f111 BM |
325 | { |
326 | size_t bits; | |
327 | ||
328 | bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); | |
329 | wsize[i] = EC_window_bits_for_scalar_size(bits); | |
194274cb | 330 | num_val += (size_t)1 << (wsize[i] - 1); |
37c660ff | 331 | wNAF[i + 1] = NULL; /* make sure we always have a pivot */ |
5784a521 | 332 | wNAF[i] = bn_compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]); |
37c660ff BM |
333 | if (wNAF[i] == NULL) |
334 | goto err; | |
335 | if (wNAF_len[i] > max_len) | |
336 | max_len = wNAF_len[i]; | |
3ba1f111 BM |
337 | } |
338 | ||
37c660ff BM |
339 | if (numblocks) |
340 | { | |
341 | /* we go here iff scalar != NULL */ | |
342 | ||
343 | if (pre_comp == NULL) | |
344 | { | |
345 | if (num_scalar != 1) | |
346 | { | |
347 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
348 | goto err; | |
349 | } | |
350 | /* we have already generated a wNAF for 'scalar' */ | |
351 | } | |
352 | else | |
353 | { | |
354 | signed char *tmp_wNAF = NULL; | |
355 | size_t tmp_len = 0; | |
356 | ||
357 | if (num_scalar != 0) | |
358 | { | |
359 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
360 | goto err; | |
361 | } | |
362 | ||
363 | /* use the window size for which we have precomputation */ | |
364 | wsize[num] = pre_comp->w; | |
5784a521 | 365 | tmp_wNAF = bn_compute_wNAF(scalar, wsize[num], &tmp_len); |
37c660ff BM |
366 | if (!tmp_wNAF) |
367 | goto err; | |
368 | ||
369 | if (tmp_len <= max_len) | |
370 | { | |
371 | /* One of the other wNAFs is at least as long | |
372 | * as the wNAF belonging to the generator, | |
373 | * so wNAF splitting will not buy us anything. */ | |
374 | ||
375 | numblocks = 1; | |
376 | totalnum = num + 1; /* don't use wNAF splitting */ | |
377 | wNAF[num] = tmp_wNAF; | |
378 | wNAF[num + 1] = NULL; | |
379 | wNAF_len[num] = tmp_len; | |
380 | if (tmp_len > max_len) | |
381 | max_len = tmp_len; | |
382 | /* pre_comp->points starts with the points that we need here: */ | |
383 | val_sub[num] = pre_comp->points; | |
384 | } | |
385 | else | |
386 | { | |
387 | /* don't include tmp_wNAF directly into wNAF array | |
388 | * - use wNAF splitting and include the blocks */ | |
389 | ||
390 | signed char *pp; | |
391 | EC_POINT **tmp_points; | |
392 | ||
393 | if (tmp_len < numblocks * blocksize) | |
394 | { | |
395 | /* possibly we can do with fewer blocks than estimated */ | |
396 | numblocks = (tmp_len + blocksize - 1) / blocksize; | |
397 | if (numblocks > pre_comp->numblocks) | |
398 | { | |
399 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
400 | goto err; | |
401 | } | |
402 | totalnum = num + numblocks; | |
403 | } | |
404 | ||
405 | /* split wNAF in 'numblocks' parts */ | |
406 | pp = tmp_wNAF; | |
407 | tmp_points = pre_comp->points; | |
408 | ||
409 | for (i = num; i < totalnum; i++) | |
410 | { | |
411 | if (i < totalnum - 1) | |
412 | { | |
413 | wNAF_len[i] = blocksize; | |
414 | if (tmp_len < blocksize) | |
415 | { | |
416 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
417 | goto err; | |
418 | } | |
419 | tmp_len -= blocksize; | |
420 | } | |
421 | else | |
422 | /* last block gets whatever is left | |
423 | * (this could be more or less than 'blocksize'!) */ | |
424 | wNAF_len[i] = tmp_len; | |
425 | ||
426 | wNAF[i + 1] = NULL; | |
427 | wNAF[i] = OPENSSL_malloc(wNAF_len[i]); | |
428 | if (wNAF[i] == NULL) | |
429 | { | |
19f6c524 | 430 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); |
37c660ff BM |
431 | OPENSSL_free(tmp_wNAF); |
432 | goto err; | |
433 | } | |
434 | memcpy(wNAF[i], pp, wNAF_len[i]); | |
435 | if (wNAF_len[i] > max_len) | |
436 | max_len = wNAF_len[i]; | |
437 | ||
438 | if (*tmp_points == NULL) | |
439 | { | |
440 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); | |
441 | OPENSSL_free(tmp_wNAF); | |
442 | goto err; | |
443 | } | |
444 | val_sub[i] = tmp_points; | |
445 | tmp_points += pre_points_per_block; | |
446 | pp += blocksize; | |
447 | } | |
448 | OPENSSL_free(tmp_wNAF); | |
449 | } | |
450 | } | |
451 | } | |
452 | ||
453 | /* All points we precompute now go into a single array 'val'. | |
454 | * 'val_sub[i]' is a pointer to the subarray for the i-th point, | |
455 | * or to a subarray of 'pre_comp->points' if we already have precomputation. */ | |
3ba1f111 | 456 | val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); |
19f6c524 BM |
457 | if (val == NULL) |
458 | { | |
459 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); | |
460 | goto err; | |
461 | } | |
3ba1f111 BM |
462 | val[num_val] = NULL; /* pivot element */ |
463 | ||
3ba1f111 BM |
464 | /* allocate points for precomputation */ |
465 | v = val; | |
37c660ff | 466 | for (i = 0; i < num + num_scalar; i++) |
3ba1f111 BM |
467 | { |
468 | val_sub[i] = v; | |
194274cb | 469 | for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) |
3ba1f111 BM |
470 | { |
471 | *v = EC_POINT_new(group); | |
472 | if (*v == NULL) goto err; | |
473 | v++; | |
474 | } | |
475 | } | |
476 | if (!(v == val + num_val)) | |
477 | { | |
7793f30e | 478 | ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); |
3ba1f111 BM |
479 | goto err; |
480 | } | |
481 | ||
37c660ff BM |
482 | if (!(tmp = EC_POINT_new(group))) |
483 | goto err; | |
3ba1f111 BM |
484 | |
485 | /* prepare precomputed values: | |
486 | * val_sub[i][0] := points[i] | |
487 | * val_sub[i][1] := 3 * points[i] | |
488 | * val_sub[i][2] := 5 * points[i] | |
489 | * ... | |
490 | */ | |
37c660ff | 491 | for (i = 0; i < num + num_scalar; i++) |
3ba1f111 BM |
492 | { |
493 | if (i < num) | |
494 | { | |
495 | if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err; | |
496 | } | |
497 | else | |
498 | { | |
499 | if (!EC_POINT_copy(val_sub[i][0], generator)) goto err; | |
500 | } | |
501 | ||
502 | if (wsize[i] > 1) | |
503 | { | |
504 | if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err; | |
194274cb | 505 | for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) |
3ba1f111 BM |
506 | { |
507 | if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err; | |
508 | } | |
509 | } | |
3ba1f111 BM |
510 | } |
511 | ||
512 | #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ | |
37c660ff BM |
513 | if (!EC_POINTs_make_affine(group, num_val, val, ctx)) |
514 | goto err; | |
3ba1f111 BM |
515 | #endif |
516 | ||
517 | r_is_at_infinity = 1; | |
518 | ||
519 | for (k = max_len - 1; k >= 0; k--) | |
520 | { | |
521 | if (!r_is_at_infinity) | |
522 | { | |
523 | if (!EC_POINT_dbl(group, r, r, ctx)) goto err; | |
524 | } | |
525 | ||
526 | for (i = 0; i < totalnum; i++) | |
527 | { | |
b77fcddb | 528 | if (wNAF_len[i] > (size_t)k) |
3ba1f111 BM |
529 | { |
530 | int digit = wNAF[i][k]; | |
531 | int is_neg; | |
532 | ||
533 | if (digit) | |
534 | { | |
535 | is_neg = digit < 0; | |
536 | ||
537 | if (is_neg) | |
538 | digit = -digit; | |
539 | ||
540 | if (is_neg != r_is_inverted) | |
541 | { | |
542 | if (!r_is_at_infinity) | |
543 | { | |
544 | if (!EC_POINT_invert(group, r, ctx)) goto err; | |
545 | } | |
546 | r_is_inverted = !r_is_inverted; | |
547 | } | |
548 | ||
549 | /* digit > 0 */ | |
550 | ||
551 | if (r_is_at_infinity) | |
552 | { | |
553 | if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) goto err; | |
554 | r_is_at_infinity = 0; | |
555 | } | |
556 | else | |
557 | { | |
558 | if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) goto err; | |
559 | } | |
560 | } | |
561 | } | |
562 | } | |
563 | } | |
564 | ||
565 | if (r_is_at_infinity) | |
566 | { | |
567 | if (!EC_POINT_set_to_infinity(group, r)) goto err; | |
568 | } | |
569 | else | |
570 | { | |
571 | if (r_is_inverted) | |
572 | if (!EC_POINT_invert(group, r, ctx)) goto err; | |
573 | } | |
574 | ||
575 | ret = 1; | |
576 | ||
577 | err: | |
578 | if (new_ctx != NULL) | |
579 | BN_CTX_free(new_ctx); | |
580 | if (tmp != NULL) | |
581 | EC_POINT_free(tmp); | |
582 | if (wsize != NULL) | |
583 | OPENSSL_free(wsize); | |
584 | if (wNAF_len != NULL) | |
585 | OPENSSL_free(wNAF_len); | |
586 | if (wNAF != NULL) | |
587 | { | |
588 | signed char **w; | |
589 | ||
590 | for (w = wNAF; *w != NULL; w++) | |
591 | OPENSSL_free(*w); | |
592 | ||
593 | OPENSSL_free(wNAF); | |
594 | } | |
595 | if (val != NULL) | |
596 | { | |
597 | for (v = val; *v != NULL; v++) | |
598 | EC_POINT_clear_free(*v); | |
599 | ||
600 | OPENSSL_free(val); | |
601 | } | |
602 | if (val_sub != NULL) | |
603 | { | |
604 | OPENSSL_free(val_sub); | |
605 | } | |
606 | return ret; | |
607 | } | |
608 | ||
38374911 | 609 | |
37c660ff BM |
610 | /* ec_wNAF_precompute_mult() |
611 | * creates an EC_PRE_COMP object with preprecomputed multiples of the generator | |
612 | * for use with wNAF splitting as implemented in ec_wNAF_mul(). | |
613 | * | |
614 | * 'pre_comp->points' is an array of multiples of the generator | |
615 | * of the following form: | |
616 | * points[0] = generator; | |
617 | * points[1] = 3 * generator; | |
618 | * ... | |
619 | * points[2^(w-1)-1] = (2^(w-1)-1) * generator; | |
620 | * points[2^(w-1)] = 2^blocksize * generator; | |
621 | * points[2^(w-1)+1] = 3 * 2^blocksize * generator; | |
622 | * ... | |
623 | * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) * generator | |
624 | * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) * generator | |
625 | * ... | |
626 | * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) * generator | |
627 | * points[2^(w-1)*numblocks] = NULL | |
7793f30e | 628 | */ |
7793f30e | 629 | int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx) |
38374911 BM |
630 | { |
631 | const EC_POINT *generator; | |
37c660ff | 632 | EC_POINT *tmp_point = NULL, *base = NULL, **var; |
38374911 BM |
633 | BN_CTX *new_ctx = NULL; |
634 | BIGNUM *order; | |
37c660ff BM |
635 | size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num; |
636 | EC_POINT **points = NULL; | |
ba729265 | 637 | EC_PRE_COMP *pre_comp; |
38374911 BM |
638 | int ret = 0; |
639 | ||
ba729265 | 640 | /* if there is an old EC_PRE_COMP object, throw it away */ |
9dd84053 | 641 | EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free); |
ba729265 BM |
642 | |
643 | if ((pre_comp = ec_pre_comp_new(group)) == NULL) | |
644 | return 0; | |
37c660ff | 645 | |
38374911 BM |
646 | generator = EC_GROUP_get0_generator(group); |
647 | if (generator == NULL) | |
648 | { | |
7793f30e | 649 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR); |
37c660ff | 650 | goto err; |
38374911 BM |
651 | } |
652 | ||
653 | if (ctx == NULL) | |
654 | { | |
655 | ctx = new_ctx = BN_CTX_new(); | |
656 | if (ctx == NULL) | |
37c660ff | 657 | goto err; |
38374911 BM |
658 | } |
659 | ||
660 | BN_CTX_start(ctx); | |
661 | order = BN_CTX_get(ctx); | |
662 | if (order == NULL) goto err; | |
663 | ||
37c660ff | 664 | if (!EC_GROUP_get_order(group, order, ctx)) goto err; |
38374911 BM |
665 | if (BN_is_zero(order)) |
666 | { | |
7793f30e | 667 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER); |
38374911 BM |
668 | goto err; |
669 | } | |
670 | ||
37c660ff | 671 | bits = BN_num_bits(order); |
82871eaa BM |
672 | /* The following parameters mean we precompute (approximately) |
673 | * one point per bit. | |
674 | * | |
675 | * TBD: The combination 8, 4 is perfect for 160 bits; for other | |
676 | * bit lengths, other parameter combinations might provide better | |
677 | * efficiency. | |
678 | */ | |
37c660ff BM |
679 | blocksize = 8; |
680 | w = 4; | |
681 | if (EC_window_bits_for_scalar_size(bits) > w) | |
682 | { | |
683 | /* let's not make the window too small ... */ | |
684 | w = EC_window_bits_for_scalar_size(bits); | |
685 | } | |
686 | ||
687 | numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks to use for wNAF splitting */ | |
688 | ||
194274cb | 689 | pre_points_per_block = (size_t)1 << (w - 1); |
37c660ff BM |
690 | num = pre_points_per_block * numblocks; /* number of points to compute and store */ |
691 | ||
692 | points = OPENSSL_malloc(sizeof (EC_POINT*)*(num + 1)); | |
693 | if (!points) | |
694 | { | |
695 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); | |
696 | goto err; | |
697 | } | |
698 | ||
699 | var = points; | |
700 | var[num] = NULL; /* pivot */ | |
701 | for (i = 0; i < num; i++) | |
702 | { | |
703 | if ((var[i] = EC_POINT_new(group)) == NULL) | |
704 | { | |
705 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); | |
706 | goto err; | |
707 | } | |
708 | } | |
38374911 | 709 | |
37c660ff BM |
710 | if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) |
711 | { | |
712 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); | |
713 | goto err; | |
714 | } | |
715 | ||
716 | if (!EC_POINT_copy(base, generator)) | |
717 | goto err; | |
718 | ||
719 | /* do the precomputation */ | |
720 | for (i = 0; i < numblocks; i++) | |
721 | { | |
722 | size_t j; | |
723 | ||
724 | if (!EC_POINT_dbl(group, tmp_point, base, ctx)) | |
725 | goto err; | |
726 | ||
727 | if (!EC_POINT_copy(*var++, base)) | |
728 | goto err; | |
729 | ||
730 | for (j = 1; j < pre_points_per_block; j++, var++) | |
731 | { | |
732 | /* calculate odd multiples of the current base point */ | |
733 | if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx)) | |
734 | goto err; | |
735 | } | |
736 | ||
737 | if (i < numblocks - 1) | |
738 | { | |
739 | /* get the next base (multiply current one by 2^blocksize) */ | |
740 | size_t k; | |
741 | ||
742 | if (blocksize <= 2) | |
743 | { | |
744 | ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERNAL_ERROR); | |
745 | goto err; | |
746 | } | |
747 | ||
748 | if (!EC_POINT_dbl(group, base, tmp_point, ctx)) | |
749 | goto err; | |
750 | for (k = 2; k < blocksize; k++) | |
751 | { | |
752 | if (!EC_POINT_dbl(group,base,base,ctx)) | |
753 | goto err; | |
754 | } | |
755 | } | |
756 | } | |
757 | ||
758 | if (!EC_POINTs_make_affine(group, num, points, ctx)) | |
759 | goto err; | |
38374911 | 760 | |
37c660ff BM |
761 | pre_comp->group = group; |
762 | pre_comp->blocksize = blocksize; | |
763 | pre_comp->numblocks = numblocks; | |
764 | pre_comp->w = w; | |
37c660ff BM |
765 | pre_comp->points = points; |
766 | points = NULL; | |
767 | pre_comp->num = num; | |
768 | ||
9dd84053 | 769 | if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp, |
ba729265 BM |
770 | ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free)) |
771 | goto err; | |
772 | pre_comp = NULL; | |
37c660ff BM |
773 | |
774 | ret = 1; | |
38374911 | 775 | err: |
eeb821f7 NL |
776 | if (ctx != NULL) |
777 | BN_CTX_end(ctx); | |
38374911 BM |
778 | if (new_ctx != NULL) |
779 | BN_CTX_free(new_ctx); | |
ba729265 BM |
780 | if (pre_comp) |
781 | ec_pre_comp_free(pre_comp); | |
37c660ff BM |
782 | if (points) |
783 | { | |
784 | EC_POINT **p; | |
785 | ||
786 | for (p = points; *p != NULL; p++) | |
787 | EC_POINT_free(*p); | |
788 | OPENSSL_free(points); | |
789 | } | |
790 | if (tmp_point) | |
791 | EC_POINT_free(tmp_point); | |
792 | if (base) | |
793 | EC_POINT_free(base); | |
38374911 BM |
794 | return ret; |
795 | } | |
7793f30e BM |
796 | |
797 | ||
37c660ff | 798 | int ec_wNAF_have_precompute_mult(const EC_GROUP *group) |
7793f30e | 799 | { |
9dd84053 | 800 | if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL) |
7793f30e | 801 | return 1; |
37c660ff BM |
802 | else |
803 | return 0; | |
7793f30e | 804 | } |