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Improve EC efficiency.
[thirdparty/openssl.git] / crypto / ec / ec_mult.c
1 /* crypto/ec/ec_mult.c */
2 /* ====================================================================
3 * Copyright (c) 1998-2001 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 #include <openssl/err.h>
57
58 #include "ec_lcl.h"
59
60
61 /* TODO: optional precomputation of multiples of the generator */
62
63
64 #if 1
65 /*
66 * wNAF-based interleaving multi-exponentation method
67 */
68
69
70
71 /* Determine the width-(w+1) Non-Adjacent Form of 'scalar'.
72 * This is an array r[] of values that are either zero or odd with an
73 * absolute value less than 2^w satisfying
74 * scalar = \sum_j r[j]*2^j
75 * where at most one of any w+1 consecutive digits is non-zero.
76 */
77 static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len, BN_CTX *ctx)
78 {
79 BIGNUM *c;
80 int ok = 0;
81 signed char *r = NULL;
82 int sign = 1;
83 int bit, next_bit, mask;
84 size_t len, j;
85
86 BN_CTX_start(ctx);
87 c = BN_CTX_get(ctx);
88 if (c == NULL) goto err;
89
90 if (w <= 0 || w > 7) /* 'unsigned char' can represent integers with absolute values less than 2^7 */
91 {
92 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
93 goto err;
94 }
95 bit = 1 << w; /* at most 128 */
96 next_bit = bit << 1; /* at most 256 */
97 mask = next_bit - 1; /* at most 255 */
98
99 if (!BN_copy(c, scalar)) goto err;
100 if (c->neg)
101 {
102 sign = -1;
103 c->neg = 0;
104 }
105
106 len = BN_num_bits(c) + 1; /* wNAF may be one digit longer than binary representation */
107 r = OPENSSL_malloc(len);
108 if (r == NULL) goto err;
109
110 j = 0;
111 while (!BN_is_zero(c))
112 {
113 int u = 0;
114
115 if (BN_is_odd(c))
116 {
117 if (c->d == NULL || c->top == 0)
118 {
119 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
120 goto err;
121 }
122 u = c->d[0] & mask;
123 if (u & bit)
124 {
125 u -= next_bit;
126 /* u < 0 */
127 if (!BN_add_word(c, -u)) goto err;
128 }
129 else
130 {
131 /* u > 0 */
132 if (!BN_sub_word(c, u)) goto err;
133 }
134
135 if (u <= -bit || u >= bit || !(u & 1) || c->neg)
136 {
137 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
138 goto err;
139 }
140 }
141
142 r[j++] = sign * u;
143
144 if (BN_is_odd(c))
145 {
146 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
147 goto err;
148 }
149 if (!BN_rshift1(c, c)) goto err;
150 }
151
152 if (j > len)
153 {
154 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
155 goto err;
156 }
157 len = j;
158 ok = 1;
159
160 err:
161 BN_CTX_end(ctx);
162 if (!ok)
163 {
164 OPENSSL_free(r);
165 r = NULL;
166 }
167 if (ok)
168 *ret_len = len;
169 return r;
170 }
171
172
173 /* TODO: table should be optimised for the wNAF-based implementation */
174 #define EC_window_bits_for_scalar_size(b) \
175 ((b) >= 2000 ? 6 : \
176 (b) >= 800 ? 5 : \
177 (b) >= 300 ? 4 : \
178 (b) >= 70 ? 3 : \
179 (b) >= 20 ? 2 : \
180 1)
181
182 /* Compute
183 * \sum scalars[i]*points[i],
184 * also including
185 * scalar*generator
186 * in the addition if scalar != NULL
187 */
188 int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
189 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
190 {
191 BN_CTX *new_ctx = NULL;
192 EC_POINT *generator = NULL;
193 EC_POINT *tmp = NULL;
194 size_t totalnum;
195 size_t i, j;
196 int k;
197 int r_is_inverted = 0;
198 int r_is_at_infinity = 1;
199 size_t *wsize = NULL; /* individual window sizes */
200 size_t *wNAF_len = NULL;
201 size_t max_len = 0;
202 signed char **wNAF = NULL; /* individual wNAFs */
203 size_t num_val;
204 EC_POINT **val = NULL; /* precomputation */
205 EC_POINT **v;
206 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */
207 int ret = 0;
208
209 if (scalar != NULL)
210 {
211 generator = EC_GROUP_get0_generator(group);
212 if (generator == NULL)
213 {
214 ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
215 return 0;
216 }
217 }
218
219 for (i = 0; i < num; i++)
220 {
221 if (group->meth != points[i]->meth)
222 {
223 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
224 return 0;
225 }
226 }
227
228 totalnum = num + (scalar != NULL);
229
230 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]);
231 wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]);
232 wNAF = OPENSSL_malloc(totalnum * sizeof wNAF[0] + 1);
233 if (wNAF != NULL)
234 {
235 wNAF[0] = NULL; /* preliminary pivot */
236 }
237 if (wsize == NULL || wNAF_len == NULL || wNAF == NULL) goto err;
238
239 /* num_val := total number of points to precompute */
240 num_val = 0;
241 for (i = 0; i < totalnum; i++)
242 {
243 size_t bits;
244
245 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
246 wsize[i] = EC_window_bits_for_scalar_size(bits);
247 num_val += 1u << (wsize[i] - 1);
248 }
249
250 /* all precomputed points go into a single array 'val',
251 * 'val_sub[i]' is a pointer to the subarray for the i-th point */
252 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
253 if (val == NULL) goto err;
254 val[num_val] = NULL; /* pivot element */
255
256 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
257 if (val_sub == NULL) goto err;
258
259 /* allocate points for precomputation */
260 v = val;
261 for (i = 0; i < totalnum; i++)
262 {
263 val_sub[i] = v;
264 for (j = 0; j < (1u << (wsize[i] - 1)); j++)
265 {
266 *v = EC_POINT_new(group);
267 if (*v == NULL) goto err;
268 v++;
269 }
270 }
271 if (!(v == val + num_val))
272 {
273 ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
274 goto err;
275 }
276
277 if (ctx == NULL)
278 {
279 ctx = new_ctx = BN_CTX_new();
280 if (ctx == NULL)
281 goto err;
282 }
283
284 tmp = EC_POINT_new(group);
285 if (tmp == NULL) goto err;
286
287 /* prepare precomputed values:
288 * val_sub[i][0] := points[i]
289 * val_sub[i][1] := 3 * points[i]
290 * val_sub[i][2] := 5 * points[i]
291 * ...
292 */
293 for (i = 0; i < totalnum; i++)
294 {
295 if (i < num)
296 {
297 if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err;
298 }
299 else
300 {
301 if (!EC_POINT_copy(val_sub[i][0], generator)) goto err;
302 }
303
304 if (wsize[i] > 1)
305 {
306 if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err;
307 for (j = 1; j < (1u << (wsize[i] - 1)); j++)
308 {
309 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
310 }
311 }
312
313 wNAF[i + 1] = NULL; /* make sure we always have a pivot */
314 wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i], ctx);
315 if (wNAF[i] == NULL) goto err;
316 if (wNAF_len[i] > max_len)
317 max_len = wNAF_len[i];
318 }
319
320 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
321 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err;
322 #endif
323
324 r_is_at_infinity = 1;
325
326 for (k = max_len - 1; k >= 0; k--)
327 {
328 if (!r_is_at_infinity)
329 {
330 if (!EC_POINT_dbl(group, r, r, ctx)) goto err;
331 }
332
333 for (i = 0; i < totalnum; i++)
334 {
335 if (wNAF_len[i] > k)
336 {
337 int digit = wNAF[i][k];
338 int is_neg;
339
340 if (digit)
341 {
342 is_neg = digit < 0;
343
344 if (is_neg)
345 digit = -digit;
346
347 if (is_neg != r_is_inverted)
348 {
349 if (!r_is_at_infinity)
350 {
351 if (!EC_POINT_invert(group, r, ctx)) goto err;
352 }
353 r_is_inverted = !r_is_inverted;
354 }
355
356 /* digit > 0 */
357
358 if (r_is_at_infinity)
359 {
360 if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) goto err;
361 r_is_at_infinity = 0;
362 }
363 else
364 {
365 if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) goto err;
366 }
367 }
368 }
369 }
370 }
371
372 if (r_is_at_infinity)
373 {
374 if (!EC_POINT_set_to_infinity(group, r)) goto err;
375 }
376 else
377 {
378 if (r_is_inverted)
379 if (!EC_POINT_invert(group, r, ctx)) goto err;
380 }
381
382 ret = 1;
383
384 err:
385 if (new_ctx != NULL)
386 BN_CTX_free(new_ctx);
387 if (tmp != NULL)
388 EC_POINT_free(tmp);
389 if (wsize != NULL)
390 OPENSSL_free(wsize);
391 if (wNAF_len != NULL)
392 OPENSSL_free(wNAF_len);
393 if (wNAF != NULL)
394 {
395 signed char **w;
396
397 for (w = wNAF; *w != NULL; w++)
398 OPENSSL_free(*w);
399
400 OPENSSL_free(wNAF);
401 }
402 if (val != NULL)
403 {
404 for (v = val; *v != NULL; v++)
405 EC_POINT_clear_free(*v);
406
407 OPENSSL_free(val);
408 }
409 if (val_sub != NULL)
410 {
411 OPENSSL_free(val_sub);
412 }
413 return ret;
414 }
415
416 #else
417
418 /*
419 * Basic interleaving multi-exponentation method
420 */
421
422
423
424 #define EC_window_bits_for_scalar_size(b) \
425 ((b) >= 2000 ? 6 : \
426 (b) >= 800 ? 5 : \
427 (b) >= 300 ? 4 : \
428 (b) >= 70 ? 3 : \
429 (b) >= 20 ? 2 : \
430 1)
431 /* For window size 'w' (w >= 2), we compute the odd multiples
432 * 1*P .. (2^w-1)*P.
433 * This accounts for 2^(w-1) point additions (neglecting constants),
434 * each of which requires 16 field multiplications (4 squarings
435 * and 12 general multiplications) in the case of curves defined
436 * over GF(p), which are the only curves we have so far.
437 *
438 * Converting these precomputed points into affine form takes
439 * three field multiplications for inverting Z and one squaring
440 * and three multiplications for adjusting X and Y, i.e.
441 * 7 multiplications in total (1 squaring and 6 general multiplications),
442 * again except for constants.
443 *
444 * The average number of windows for a 'b' bit scalar is roughly
445 * b/(w+1).
446 * Each of these windows (except possibly for the first one, but
447 * we are ignoring constants anyway) requires one point addition.
448 * As the precomputed table stores points in affine form, these
449 * additions take only 11 field multiplications each (3 squarings
450 * and 8 general multiplications).
451 *
452 * So the total workload, except for constants, is
453 *
454 * 2^(w-1)*[5 squarings + 18 multiplications]
455 * + (b/(w+1))*[3 squarings + 8 multiplications]
456 *
457 * If we assume that 10 squarings are as costly as 9 multiplications,
458 * our task is to find the 'w' that, given 'b', minimizes
459 *
460 * 2^(w-1)*(5*9 + 18*10) + (b/(w+1))*(3*9 + 8*10)
461 * = 2^(w-1)*225 + (b/(w+1))*107.
462 *
463 * Thus optimal window sizes should be roughly as follows:
464 *
465 * w >= 6 if b >= 1414
466 * w = 5 if 1413 >= b >= 505
467 * w = 4 if 504 >= b >= 169
468 * w = 3 if 168 >= b >= 51
469 * w = 2 if 50 >= b >= 13
470 * w = 1 if 12 >= b
471 *
472 * If we assume instead that squarings are exactly as costly as
473 * multiplications, we have to minimize
474 * 2^(w-1)*23 + (b/(w+1))*11.
475 *
476 * This gives us the following (nearly unchanged) table of optimal
477 * windows sizes:
478 *
479 * w >= 6 if b >= 1406
480 * w = 5 if 1405 >= b >= 502
481 * w = 4 if 501 >= b >= 168
482 * w = 3 if 167 >= b >= 51
483 * w = 2 if 50 >= b >= 13
484 * w = 1 if 12 >= b
485 *
486 * Note that neither table tries to take into account memory usage
487 * (allocation overhead, code locality etc.). Actual timings with
488 * NIST curves P-192, P-224, and P-256 with scalars of 192, 224,
489 * and 256 bits, respectively, show that w = 3 (instead of 4) is
490 * preferrable; timings with NIST curve P-384 and 384-bit scalars
491 * confirm that w = 4 is optimal for this case; and timings with
492 * NIST curve P-521 and 521-bit scalars show that w = 4 (instead
493 * of 5) is preferrable. So we generously round up all the
494 * boundaries and use the following table:
495 *
496 * w >= 6 if b >= 2000
497 * w = 5 if 1999 >= b >= 800
498 * w = 4 if 799 >= b >= 300
499 * w = 3 if 299 >= b >= 70
500 * w = 2 if 69 >= b >= 20
501 * w = 1 if 19 >= b
502 */
503
504 int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
505 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
506 {
507 BN_CTX *new_ctx = NULL;
508 EC_POINT *generator = NULL;
509 EC_POINT *tmp = NULL;
510 size_t totalnum;
511 size_t i, j;
512 int k, t;
513 int r_is_at_infinity = 1;
514 size_t max_bits = 0;
515 size_t *wsize = NULL; /* individual window sizes */
516 unsigned long *wbits = NULL; /* individual window contents */
517 int *wpos = NULL; /* position of bottom bit of current individual windows
518 * (wpos[i] is valid if wbits[i] != 0) */
519 size_t num_val;
520 EC_POINT **val = NULL; /* precomputation */
521 EC_POINT **v;
522 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */
523 int ret = 0;
524
525 if (scalar != NULL)
526 {
527 generator = EC_GROUP_get0_generator(group);
528 if (generator == NULL)
529 {
530 ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
531 return 0;
532 }
533 }
534
535 for (i = 0; i < num; i++)
536 {
537 if (group->meth != points[i]->meth)
538 {
539 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
540 return 0;
541 }
542 }
543
544 totalnum = num + (scalar != NULL);
545
546 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]);
547 wbits = OPENSSL_malloc(totalnum * sizeof wbits[0]);
548 wpos = OPENSSL_malloc(totalnum * sizeof wpos[0]);
549 if (wsize == NULL || wbits == NULL || wpos == NULL) goto err;
550
551 /* num_val := total number of points to precompute */
552 num_val = 0;
553 for (i = 0; i < totalnum; i++)
554 {
555 size_t bits;
556
557 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
558 wsize[i] = EC_window_bits_for_scalar_size(bits);
559 num_val += 1u << (wsize[i] - 1);
560 if (bits > max_bits)
561 max_bits = bits;
562 wbits[i] = 0;
563 wpos[i] = 0;
564 }
565
566 /* all precomputed points go into a single array 'val',
567 * 'val_sub[i]' is a pointer to the subarray for the i-th point */
568 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
569 if (val == NULL) goto err;
570 val[num_val] = NULL; /* pivot element */
571
572 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
573 if (val_sub == NULL) goto err;
574
575 /* allocate points for precomputation */
576 v = val;
577 for (i = 0; i < totalnum; i++)
578 {
579 val_sub[i] = v;
580 for (j = 0; j < (1u << (wsize[i] - 1)); j++)
581 {
582 *v = EC_POINT_new(group);
583 if (*v == NULL) goto err;
584 v++;
585 }
586 }
587 if (!(v == val + num_val))
588 {
589 ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
590 goto err;
591 }
592
593 if (ctx == NULL)
594 {
595 ctx = new_ctx = BN_CTX_new();
596 if (ctx == NULL)
597 goto err;
598 }
599
600 tmp = EC_POINT_new(group);
601 if (tmp == NULL) goto err;
602
603 /* prepare precomputed values:
604 * val_sub[i][0] := points[i]
605 * val_sub[i][1] := 3 * points[i]
606 * val_sub[i][2] := 5 * points[i]
607 * ...
608 */
609 for (i = 0; i < totalnum; i++)
610 {
611 if (i < num)
612 {
613 if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err;
614 if (scalars[i]->neg)
615 {
616 if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err;
617 }
618 }
619 else
620 {
621 if (!EC_POINT_copy(val_sub[i][0], generator)) goto err;
622 if (scalar->neg)
623 {
624 if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err;
625 }
626 }
627
628 if (wsize[i] > 1)
629 {
630 if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err;
631 for (j = 1; j < (1u << (wsize[i] - 1)); j++)
632 {
633 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
634 }
635 }
636 }
637
638 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
639 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err;
640 #endif
641
642 r_is_at_infinity = 1;
643
644 for (k = max_bits - 1; k >= 0; k--)
645 {
646 if (!r_is_at_infinity)
647 {
648 if (!EC_POINT_dbl(group, r, r, ctx)) goto err;
649 }
650
651 for (i = 0; i < totalnum; i++)
652 {
653 if (wbits[i] == 0)
654 {
655 const BIGNUM *s;
656
657 s = i < num ? scalars[i] : scalar;
658
659 if (BN_is_bit_set(s, k))
660 {
661 /* look at bits k - wsize[i] + 1 .. k for this window */
662 t = k - wsize[i] + 1;
663 while (!BN_is_bit_set(s, t)) /* BN_is_bit_set is false for t < 0 */
664 t++;
665 wpos[i] = t;
666 wbits[i] = 1;
667 for (t = k - 1; t >= wpos[i]; t--)
668 {
669 wbits[i] <<= 1;
670 if (BN_is_bit_set(s, t))
671 wbits[i]++;
672 }
673 /* now wbits[i] is the odd bit pattern at bits wpos[i] .. k */
674 }
675 }
676
677 if ((wbits[i] != 0) && (wpos[i] == k))
678 {
679 if (r_is_at_infinity)
680 {
681 if (!EC_POINT_copy(r, val_sub[i][wbits[i] >> 1])) goto err;
682 r_is_at_infinity = 0;
683 }
684 else
685 {
686 if (!EC_POINT_add(group, r, r, val_sub[i][wbits[i] >> 1], ctx)) goto err;
687 }
688 wbits[i] = 0;
689 }
690 }
691 }
692
693 if (r_is_at_infinity)
694 if (!EC_POINT_set_to_infinity(group, r)) goto err;
695
696 ret = 1;
697
698 err:
699 if (new_ctx != NULL)
700 BN_CTX_free(new_ctx);
701 if (tmp != NULL)
702 EC_POINT_free(tmp);
703 if (wsize != NULL)
704 OPENSSL_free(wsize);
705 if (wbits != NULL)
706 OPENSSL_free(wbits);
707 if (wpos != NULL)
708 OPENSSL_free(wpos);
709 if (val != NULL)
710 {
711 for (v = val; *v != NULL; v++)
712 EC_POINT_clear_free(*v);
713
714 OPENSSL_free(val);
715 }
716 if (val_sub != NULL)
717 {
718 OPENSSL_free(val_sub);
719 }
720 return ret;
721 }
722 #endif
723
724
725 int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar, const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx)
726 {
727 const EC_POINT *points[1];
728 const BIGNUM *scalars[1];
729
730 points[0] = point;
731 scalars[0] = p_scalar;
732
733 return EC_POINTs_mul(group, r, g_scalar, (point != NULL && p_scalar != NULL), points, scalars, ctx);
734 }
735
736
737 int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
738 {
739 const EC_POINT *generator;
740 BN_CTX *new_ctx = NULL;
741 BIGNUM *order;
742 int ret = 0;
743
744 generator = EC_GROUP_get0_generator(group);
745 if (generator == NULL)
746 {
747 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR);
748 return 0;
749 }
750
751 if (ctx == NULL)
752 {
753 ctx = new_ctx = BN_CTX_new();
754 if (ctx == NULL)
755 return 0;
756 }
757
758 BN_CTX_start(ctx);
759 order = BN_CTX_get(ctx);
760 if (order == NULL) goto err;
761
762 if (!EC_GROUP_get_order(group, order, ctx)) return 0;
763 if (BN_is_zero(order))
764 {
765 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER);
766 goto err;
767 }
768
769 /* TODO */
770
771 ret = 1;
772
773 err:
774 BN_CTX_end(ctx);
775 if (new_ctx != NULL)
776 BN_CTX_free(new_ctx);
777 return ret;
778 }
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