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[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 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>)
68 */
69
70
71
72 /* Determine the width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
73 * This is an array r[] of values that are either zero or odd with an
74 * absolute value less than 2^w satisfying
75 * scalar = \sum_j r[j]*2^j
76 * where at most one of any w+1 consecutive digits is non-zero.
77 */
78 static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len, BN_CTX *ctx)
79 {
80 BIGNUM *c;
81 int ok = 0;
82 signed char *r = NULL;
83 int sign = 1;
84 int bit, next_bit, mask;
85 size_t len = 0, j;
86
87 BN_CTX_start(ctx);
88 c = BN_CTX_get(ctx);
89 if (c == NULL) goto err;
90
91 if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
92 {
93 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
94 goto err;
95 }
96 bit = 1 << w; /* at most 128 */
97 next_bit = bit << 1; /* at most 256 */
98 mask = next_bit - 1; /* at most 255 */
99
100 if (!BN_copy(c, scalar)) goto err;
101 if (c->neg)
102 {
103 sign = -1;
104 c->neg = 0;
105 }
106
107 len = BN_num_bits(c) + 1; /* wNAF may be one digit longer than binary representation */
108 r = OPENSSL_malloc(len);
109 if (r == NULL) goto err;
110
111 j = 0;
112 while (!BN_is_zero(c))
113 {
114 int u = 0;
115
116 if (BN_is_odd(c))
117 {
118 if (c->d == NULL || c->top == 0)
119 {
120 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
121 goto err;
122 }
123 u = c->d[0] & mask;
124 if (u & bit)
125 {
126 u -= next_bit;
127 /* u < 0 */
128 if (!BN_add_word(c, -u)) goto err;
129 }
130 else
131 {
132 /* u > 0 */
133 if (!BN_sub_word(c, u)) goto err;
134 }
135
136 if (u <= -bit || u >= bit || !(u & 1) || c->neg)
137 {
138 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
139 goto err;
140 }
141 }
142
143 r[j++] = sign * u;
144
145 if (BN_is_odd(c))
146 {
147 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
148 goto err;
149 }
150 if (!BN_rshift1(c, c)) goto err;
151 }
152
153 if (j > len)
154 {
155 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
156 goto err;
157 }
158 len = j;
159 ok = 1;
160
161 err:
162 BN_CTX_end(ctx);
163 if (!ok)
164 {
165 OPENSSL_free(r);
166 r = NULL;
167 }
168 if (ok)
169 *ret_len = len;
170 return r;
171 }
172
173
174 /* TODO: table should be optimised for the wNAF-based implementation,
175 * sometimes smaller windows will give better performance
176 * (thus the boundaries should be increased)
177 */
178 #define EC_window_bits_for_scalar_size(b) \
179 ((b) >= 2000 ? 6 : \
180 (b) >= 800 ? 5 : \
181 (b) >= 300 ? 4 : \
182 (b) >= 70 ? 3 : \
183 (b) >= 20 ? 2 : \
184 1)
185
186 /* Compute
187 * \sum scalars[i]*points[i],
188 * also including
189 * scalar*generator
190 * in the addition if scalar != NULL
191 */
192 int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
193 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
194 {
195 BN_CTX *new_ctx = NULL;
196 EC_POINT *generator = NULL;
197 EC_POINT *tmp = NULL;
198 size_t totalnum;
199 size_t i, j;
200 int k;
201 int r_is_inverted = 0;
202 int r_is_at_infinity = 1;
203 size_t *wsize = NULL; /* individual window sizes */
204 signed char **wNAF = NULL; /* individual wNAFs */
205 size_t *wNAF_len = NULL;
206 size_t max_len = 0;
207 size_t num_val;
208 EC_POINT **val = NULL; /* precomputation */
209 EC_POINT **v;
210 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */
211 int ret = 0;
212
213 if (scalar != NULL)
214 {
215 generator = EC_GROUP_get0_generator(group);
216 if (generator == NULL)
217 {
218 ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
219 return 0;
220 }
221 }
222
223 for (i = 0; i < num; i++)
224 {
225 if (group->meth != points[i]->meth)
226 {
227 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
228 return 0;
229 }
230 }
231
232 totalnum = num + (scalar != NULL);
233
234 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]);
235 wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]);
236 wNAF = OPENSSL_malloc(totalnum * sizeof wNAF[0] + 1);
237 if (wNAF != NULL)
238 {
239 wNAF[0] = NULL; /* preliminary pivot */
240 }
241 if (wsize == NULL || wNAF_len == NULL || wNAF == NULL) goto err;
242
243 /* num_val := total number of points to precompute */
244 num_val = 0;
245 for (i = 0; i < totalnum; i++)
246 {
247 size_t bits;
248
249 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
250 wsize[i] = EC_window_bits_for_scalar_size(bits);
251 num_val += 1u << (wsize[i] - 1);
252 }
253
254 /* all precomputed points go into a single array 'val',
255 * 'val_sub[i]' is a pointer to the subarray for the i-th point */
256 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
257 if (val == NULL) goto err;
258 val[num_val] = NULL; /* pivot element */
259
260 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
261 if (val_sub == NULL) goto err;
262
263 /* allocate points for precomputation */
264 v = val;
265 for (i = 0; i < totalnum; i++)
266 {
267 val_sub[i] = v;
268 for (j = 0; j < (1u << (wsize[i] - 1)); j++)
269 {
270 *v = EC_POINT_new(group);
271 if (*v == NULL) goto err;
272 v++;
273 }
274 }
275 if (!(v == val + num_val))
276 {
277 ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
278 goto err;
279 }
280
281 if (ctx == NULL)
282 {
283 ctx = new_ctx = BN_CTX_new();
284 if (ctx == NULL)
285 goto err;
286 }
287
288 tmp = EC_POINT_new(group);
289 if (tmp == NULL) goto err;
290
291 /* prepare precomputed values:
292 * val_sub[i][0] := points[i]
293 * val_sub[i][1] := 3 * points[i]
294 * val_sub[i][2] := 5 * points[i]
295 * ...
296 */
297 for (i = 0; i < totalnum; i++)
298 {
299 if (i < num)
300 {
301 if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err;
302 }
303 else
304 {
305 if (!EC_POINT_copy(val_sub[i][0], generator)) goto err;
306 }
307
308 if (wsize[i] > 1)
309 {
310 if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err;
311 for (j = 1; j < (1u << (wsize[i] - 1)); j++)
312 {
313 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
314 }
315 }
316
317 wNAF[i + 1] = NULL; /* make sure we always have a pivot */
318 wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i], ctx);
319 if (wNAF[i] == NULL) goto err;
320 if (wNAF_len[i] > max_len)
321 max_len = wNAF_len[i];
322 }
323
324 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
325 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err;
326 #endif
327
328 r_is_at_infinity = 1;
329
330 for (k = max_len - 1; k >= 0; k--)
331 {
332 if (!r_is_at_infinity)
333 {
334 if (!EC_POINT_dbl(group, r, r, ctx)) goto err;
335 }
336
337 for (i = 0; i < totalnum; i++)
338 {
339 if (wNAF_len[i] > (size_t)k)
340 {
341 int digit = wNAF[i][k];
342 int is_neg;
343
344 if (digit)
345 {
346 is_neg = digit < 0;
347
348 if (is_neg)
349 digit = -digit;
350
351 if (is_neg != r_is_inverted)
352 {
353 if (!r_is_at_infinity)
354 {
355 if (!EC_POINT_invert(group, r, ctx)) goto err;
356 }
357 r_is_inverted = !r_is_inverted;
358 }
359
360 /* digit > 0 */
361
362 if (r_is_at_infinity)
363 {
364 if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) goto err;
365 r_is_at_infinity = 0;
366 }
367 else
368 {
369 if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) goto err;
370 }
371 }
372 }
373 }
374 }
375
376 if (r_is_at_infinity)
377 {
378 if (!EC_POINT_set_to_infinity(group, r)) goto err;
379 }
380 else
381 {
382 if (r_is_inverted)
383 if (!EC_POINT_invert(group, r, ctx)) goto err;
384 }
385
386 ret = 1;
387
388 err:
389 if (new_ctx != NULL)
390 BN_CTX_free(new_ctx);
391 if (tmp != NULL)
392 EC_POINT_free(tmp);
393 if (wsize != NULL)
394 OPENSSL_free(wsize);
395 if (wNAF_len != NULL)
396 OPENSSL_free(wNAF_len);
397 if (wNAF != NULL)
398 {
399 signed char **w;
400
401 for (w = wNAF; *w != NULL; w++)
402 OPENSSL_free(*w);
403
404 OPENSSL_free(wNAF);
405 }
406 if (val != NULL)
407 {
408 for (v = val; *v != NULL; v++)
409 EC_POINT_clear_free(*v);
410
411 OPENSSL_free(val);
412 }
413 if (val_sub != NULL)
414 {
415 OPENSSL_free(val_sub);
416 }
417 return ret;
418 }
419
420 #else
421
422 /*
423 * Basic interleaving multi-exponentation method
424 */
425
426
427
428 #define EC_window_bits_for_scalar_size(b) \
429 ((b) >= 2000 ? 6 : \
430 (b) >= 800 ? 5 : \
431 (b) >= 300 ? 4 : \
432 (b) >= 70 ? 3 : \
433 (b) >= 20 ? 2 : \
434 1)
435 /* For window size 'w' (w >= 2), we compute the odd multiples
436 * 1*P .. (2^w-1)*P.
437 * This accounts for 2^(w-1) point additions (neglecting constants),
438 * each of which requires 16 field multiplications (4 squarings
439 * and 12 general multiplications) in the case of curves defined
440 * over GF(p), which are the only curves we have so far.
441 *
442 * Converting these precomputed points into affine form takes
443 * three field multiplications for inverting Z and one squaring
444 * and three multiplications for adjusting X and Y, i.e.
445 * 7 multiplications in total (1 squaring and 6 general multiplications),
446 * again except for constants.
447 *
448 * The average number of windows for a 'b' bit scalar is roughly
449 * b/(w+1).
450 * Each of these windows (except possibly for the first one, but
451 * we are ignoring constants anyway) requires one point addition.
452 * As the precomputed table stores points in affine form, these
453 * additions take only 11 field multiplications each (3 squarings
454 * and 8 general multiplications).
455 *
456 * So the total workload, except for constants, is
457 *
458 * 2^(w-1)*[5 squarings + 18 multiplications]
459 * + (b/(w+1))*[3 squarings + 8 multiplications]
460 *
461 * If we assume that 10 squarings are as costly as 9 multiplications,
462 * our task is to find the 'w' that, given 'b', minimizes
463 *
464 * 2^(w-1)*(5*9 + 18*10) + (b/(w+1))*(3*9 + 8*10)
465 * = 2^(w-1)*225 + (b/(w+1))*107.
466 *
467 * Thus optimal window sizes should be roughly as follows:
468 *
469 * w >= 6 if b >= 1414
470 * w = 5 if 1413 >= b >= 505
471 * w = 4 if 504 >= b >= 169
472 * w = 3 if 168 >= b >= 51
473 * w = 2 if 50 >= b >= 13
474 * w = 1 if 12 >= b
475 *
476 * If we assume instead that squarings are exactly as costly as
477 * multiplications, we have to minimize
478 * 2^(w-1)*23 + (b/(w+1))*11.
479 *
480 * This gives us the following (nearly unchanged) table of optimal
481 * windows sizes:
482 *
483 * w >= 6 if b >= 1406
484 * w = 5 if 1405 >= b >= 502
485 * w = 4 if 501 >= b >= 168
486 * w = 3 if 167 >= b >= 51
487 * w = 2 if 50 >= b >= 13
488 * w = 1 if 12 >= b
489 *
490 * Note that neither table tries to take into account memory usage
491 * (allocation overhead, code locality etc.). Actual timings with
492 * NIST curves P-192, P-224, and P-256 with scalars of 192, 224,
493 * and 256 bits, respectively, show that w = 3 (instead of 4) is
494 * preferrable; timings with NIST curve P-384 and 384-bit scalars
495 * confirm that w = 4 is optimal for this case; and timings with
496 * NIST curve P-521 and 521-bit scalars show that w = 4 (instead
497 * of 5) is preferrable. So we generously round up all the
498 * boundaries and use the following table:
499 *
500 * w >= 6 if b >= 2000
501 * w = 5 if 1999 >= b >= 800
502 * w = 4 if 799 >= b >= 300
503 * w = 3 if 299 >= b >= 70
504 * w = 2 if 69 >= b >= 20
505 * w = 1 if 19 >= b
506 */
507
508 int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
509 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
510 {
511 BN_CTX *new_ctx = NULL;
512 EC_POINT *generator = NULL;
513 EC_POINT *tmp = NULL;
514 size_t totalnum;
515 size_t i, j;
516 int k, t;
517 int r_is_at_infinity = 1;
518 size_t max_bits = 0;
519 size_t *wsize = NULL; /* individual window sizes */
520 unsigned long *wbits = NULL; /* individual window contents */
521 int *wpos = NULL; /* position of bottom bit of current individual windows
522 * (wpos[i] is valid if wbits[i] != 0) */
523 size_t num_val;
524 EC_POINT **val = NULL; /* precomputation */
525 EC_POINT **v;
526 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */
527 int ret = 0;
528
529 if (scalar != NULL)
530 {
531 generator = EC_GROUP_get0_generator(group);
532 if (generator == NULL)
533 {
534 ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
535 return 0;
536 }
537 }
538
539 for (i = 0; i < num; i++)
540 {
541 if (group->meth != points[i]->meth)
542 {
543 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
544 return 0;
545 }
546 }
547
548 totalnum = num + (scalar != NULL);
549
550 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]);
551 wbits = OPENSSL_malloc(totalnum * sizeof wbits[0]);
552 wpos = OPENSSL_malloc(totalnum * sizeof wpos[0]);
553 if (wsize == NULL || wbits == NULL || wpos == NULL) goto err;
554
555 /* num_val := total number of points to precompute */
556 num_val = 0;
557 for (i = 0; i < totalnum; i++)
558 {
559 size_t bits;
560
561 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
562 wsize[i] = EC_window_bits_for_scalar_size(bits);
563 num_val += 1u << (wsize[i] - 1);
564 if (bits > max_bits)
565 max_bits = bits;
566 wbits[i] = 0;
567 wpos[i] = 0;
568 }
569
570 /* all precomputed points go into a single array 'val',
571 * 'val_sub[i]' is a pointer to the subarray for the i-th point */
572 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
573 if (val == NULL) goto err;
574 val[num_val] = NULL; /* pivot element */
575
576 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
577 if (val_sub == NULL) goto err;
578
579 /* allocate points for precomputation */
580 v = val;
581 for (i = 0; i < totalnum; i++)
582 {
583 val_sub[i] = v;
584 for (j = 0; j < (1u << (wsize[i] - 1)); j++)
585 {
586 *v = EC_POINT_new(group);
587 if (*v == NULL) goto err;
588 v++;
589 }
590 }
591 if (!(v == val + num_val))
592 {
593 ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
594 goto err;
595 }
596
597 if (ctx == NULL)
598 {
599 ctx = new_ctx = BN_CTX_new();
600 if (ctx == NULL)
601 goto err;
602 }
603
604 tmp = EC_POINT_new(group);
605 if (tmp == NULL) goto err;
606
607 /* prepare precomputed values:
608 * val_sub[i][0] := points[i]
609 * val_sub[i][1] := 3 * points[i]
610 * val_sub[i][2] := 5 * points[i]
611 * ...
612 */
613 for (i = 0; i < totalnum; i++)
614 {
615 if (i < num)
616 {
617 if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err;
618 if (scalars[i]->neg)
619 {
620 if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err;
621 }
622 }
623 else
624 {
625 if (!EC_POINT_copy(val_sub[i][0], generator)) goto err;
626 if (scalar->neg)
627 {
628 if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err;
629 }
630 }
631
632 if (wsize[i] > 1)
633 {
634 if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err;
635 for (j = 1; j < (1u << (wsize[i] - 1)); j++)
636 {
637 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
638 }
639 }
640 }
641
642 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
643 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err;
644 #endif
645
646 r_is_at_infinity = 1;
647
648 for (k = max_bits - 1; k >= 0; k--)
649 {
650 if (!r_is_at_infinity)
651 {
652 if (!EC_POINT_dbl(group, r, r, ctx)) goto err;
653 }
654
655 for (i = 0; i < totalnum; i++)
656 {
657 if (wbits[i] == 0)
658 {
659 const BIGNUM *s;
660
661 s = i < num ? scalars[i] : scalar;
662
663 if (BN_is_bit_set(s, k))
664 {
665 /* look at bits k - wsize[i] + 1 .. k for this window */
666 t = k - wsize[i] + 1;
667 while (!BN_is_bit_set(s, t)) /* BN_is_bit_set is false for t < 0 */
668 t++;
669 wpos[i] = t;
670 wbits[i] = 1;
671 for (t = k - 1; t >= wpos[i]; t--)
672 {
673 wbits[i] <<= 1;
674 if (BN_is_bit_set(s, t))
675 wbits[i]++;
676 }
677 /* now wbits[i] is the odd bit pattern at bits wpos[i] .. k */
678 }
679 }
680
681 if ((wbits[i] != 0) && (wpos[i] == k))
682 {
683 if (r_is_at_infinity)
684 {
685 if (!EC_POINT_copy(r, val_sub[i][wbits[i] >> 1])) goto err;
686 r_is_at_infinity = 0;
687 }
688 else
689 {
690 if (!EC_POINT_add(group, r, r, val_sub[i][wbits[i] >> 1], ctx)) goto err;
691 }
692 wbits[i] = 0;
693 }
694 }
695 }
696
697 if (r_is_at_infinity)
698 if (!EC_POINT_set_to_infinity(group, r)) goto err;
699
700 ret = 1;
701
702 err:
703 if (new_ctx != NULL)
704 BN_CTX_free(new_ctx);
705 if (tmp != NULL)
706 EC_POINT_free(tmp);
707 if (wsize != NULL)
708 OPENSSL_free(wsize);
709 if (wbits != NULL)
710 OPENSSL_free(wbits);
711 if (wpos != NULL)
712 OPENSSL_free(wpos);
713 if (val != NULL)
714 {
715 for (v = val; *v != NULL; v++)
716 EC_POINT_clear_free(*v);
717
718 OPENSSL_free(val);
719 }
720 if (val_sub != NULL)
721 {
722 OPENSSL_free(val_sub);
723 }
724 return ret;
725 }
726 #endif
727
728
729 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)
730 {
731 const EC_POINT *points[1];
732 const BIGNUM *scalars[1];
733
734 points[0] = point;
735 scalars[0] = p_scalar;
736
737 return EC_POINTs_mul(group, r, g_scalar, (point != NULL && p_scalar != NULL), points, scalars, ctx);
738 }
739
740
741 int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
742 {
743 const EC_POINT *generator;
744 BN_CTX *new_ctx = NULL;
745 BIGNUM *order;
746 int ret = 0;
747
748 generator = EC_GROUP_get0_generator(group);
749 if (generator == NULL)
750 {
751 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR);
752 return 0;
753 }
754
755 if (ctx == NULL)
756 {
757 ctx = new_ctx = BN_CTX_new();
758 if (ctx == NULL)
759 return 0;
760 }
761
762 BN_CTX_start(ctx);
763 order = BN_CTX_get(ctx);
764 if (order == NULL) goto err;
765
766 if (!EC_GROUP_get_order(group, order, ctx)) return 0;
767 if (BN_is_zero(order))
768 {
769 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER);
770 goto err;
771 }
772
773 /* TODO */
774
775 ret = 1;
776
777 err:
778 BN_CTX_end(ctx);
779 if (new_ctx != NULL)
780 BN_CTX_free(new_ctx);
781 return ret;
782 }
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