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00-base-templates.conf: engage x25519-ppc64 module.
[thirdparty/openssl.git] / crypto / ec / ecp_smpl.c
CommitLineData
0f113f3e 1/*
83cf7abf 2 * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
aa8f3d76 3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
f8fe20e0 4 *
aa6bb135
RS		 5 * Licensed under the OpenSSL license (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
f8fe20e0 9 */
aa6bb135 10
60428dbf 11#include <openssl/err.h>
02cbedc3 12#include <openssl/symhacks.h>
60428dbf 13
f8fe20e0 14#include "ec_lcl.h"
0657bf9c 15
0657bf9c 16const EC_METHOD *EC_GFp_simple_method(void)
0f113f3e
MC		 17{
18 static const EC_METHOD ret = {
19 EC_FLAGS_DEFAULT_OCT,
20 NID_X9_62_prime_field,
21 ec_GFp_simple_group_init,
22 ec_GFp_simple_group_finish,
23 ec_GFp_simple_group_clear_finish,
24 ec_GFp_simple_group_copy,
25 ec_GFp_simple_group_set_curve,
26 ec_GFp_simple_group_get_curve,
27 ec_GFp_simple_group_get_degree,
9ff9bccc 28 ec_group_simple_order_bits,
0f113f3e
MC		 29 ec_GFp_simple_group_check_discriminant,
30 ec_GFp_simple_point_init,
31 ec_GFp_simple_point_finish,
32 ec_GFp_simple_point_clear_finish,
33 ec_GFp_simple_point_copy,
34 ec_GFp_simple_point_set_to_infinity,
35 ec_GFp_simple_set_Jprojective_coordinates_GFp,
36 ec_GFp_simple_get_Jprojective_coordinates_GFp,
37 ec_GFp_simple_point_set_affine_coordinates,
38 ec_GFp_simple_point_get_affine_coordinates,
39 0, 0, 0,
40 ec_GFp_simple_add,
41 ec_GFp_simple_dbl,
42 ec_GFp_simple_invert,
43 ec_GFp_simple_is_at_infinity,
44 ec_GFp_simple_is_on_curve,
45 ec_GFp_simple_cmp,
46 ec_GFp_simple_make_affine,
47 ec_GFp_simple_points_make_affine,
48 0 /* mul */ ,
49 0 /* precompute_mult */ ,
50 0 /* have_precompute_mult */ ,
51 ec_GFp_simple_field_mul,
52 ec_GFp_simple_field_sqr,
53 0 /* field_div */ ,
54 0 /* field_encode */ ,
55 0 /* field_decode */ ,
9ff9bccc
DSH		 56 0, /* field_set_to_one */
57 ec_key_simple_priv2oct,
58 ec_key_simple_oct2priv,
59 0, /* set private */
60 ec_key_simple_generate_key,
61 ec_key_simple_check_key,
62 ec_key_simple_generate_public_key,
63 0, /* keycopy */
64 0, /* keyfinish */
f667820c
SH		 65 ecdh_simple_compute_key,
66 0, /* field_inverse_mod_ord */
37124360
NT		 67 ec_GFp_simple_blind_coordinates,
68 0, /* ladder_pre */
69 0, /* ladder_step */
70 0 /* ladder_post */
0f113f3e
MC		 71 };
72
73 return &ret;
74}
60428dbf 75
3a83462d
MC		 76/*
77 * Most method functions in this file are designed to work with
922fa76e
BM		 78 * non-trivial representations of field elements if necessary
79 * (see ecp_mont.c): while standard modular addition and subtraction
80 * are used, the field_mul and field_sqr methods will be used for
81 * multiplication, and field_encode and field_decode (if defined)
82 * will be used for converting between representations.
3a83462d 83 *
922fa76e
BM		 84 * Functions ec_GFp_simple_points_make_affine() and
85 * ec_GFp_simple_point_get_affine_coordinates() specifically assume
86 * that if a non-trivial representation is used, it is a Montgomery
87 * representation (i.e. 'encoding' means multiplying by some factor R).
88 */
89
60428dbf 90int ec_GFp_simple_group_init(EC_GROUP *group)
0f113f3e
MC		 91{
92 group->field = BN_new();
93 group->a = BN_new();
94 group->b = BN_new();
90945fa3 95 if (group->field == NULL || group->a == NULL || group->b == NULL) {
a3853772
RS		 96 BN_free(group->field);
97 BN_free(group->a);
98 BN_free(group->b);
0f113f3e
MC		 99 return 0;
100 }
101 group->a_is_minus3 = 0;
102 return 1;
103}
60428dbf 104
bb62a8b0 105void ec_GFp_simple_group_finish(EC_GROUP *group)
0f113f3e
MC		 106{
107 BN_free(group->field);
108 BN_free(group->a);
109 BN_free(group->b);
110}
bb62a8b0
BM		 111
112void ec_GFp_simple_group_clear_finish(EC_GROUP *group)
0f113f3e
MC		 113{
114 BN_clear_free(group->field);
115 BN_clear_free(group->a);
116 BN_clear_free(group->b);
117}
bb62a8b0
BM		 118
119int ec_GFp_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src)
0f113f3e
MC		 120{
121 if (!BN_copy(dest->field, src->field))
122 return 0;
123 if (!BN_copy(dest->a, src->a))
124 return 0;
125 if (!BN_copy(dest->b, src->b))
126 return 0;
bb62a8b0 127
0f113f3e 128 dest->a_is_minus3 = src->a_is_minus3;
bb62a8b0 129
0f113f3e
MC		 130 return 1;
131}
bb62a8b0 132
35b73a1f 133int ec_GFp_simple_group_set_curve(EC_GROUP *group,
0f113f3e
MC		 134 const BIGNUM *p, const BIGNUM *a,
135 const BIGNUM *b, BN_CTX *ctx)
136{
137 int ret = 0;
138 BN_CTX *new_ctx = NULL;
139 BIGNUM *tmp_a;
140
141 /* p must be a prime > 3 */
142 if (BN_num_bits(p) <= 2 || !BN_is_odd(p)) {
143 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE, EC_R_INVALID_FIELD);
144 return 0;
145 }
146
147 if (ctx == NULL) {
148 ctx = new_ctx = BN_CTX_new();
149 if (ctx == NULL)
150 return 0;
151 }
152
153 BN_CTX_start(ctx);
154 tmp_a = BN_CTX_get(ctx);
155 if (tmp_a == NULL)
156 goto err;
157
158 /* group->field */
159 if (!BN_copy(group->field, p))
160 goto err;
161 BN_set_negative(group->field, 0);
162
163 /* group->a */
164 if (!BN_nnmod(tmp_a, a, p, ctx))
165 goto err;
166 if (group->meth->field_encode) {
167 if (!group->meth->field_encode(group, group->a, tmp_a, ctx))
168 goto err;
169 } else if (!BN_copy(group->a, tmp_a))
170 goto err;
171
172 /* group->b */
173 if (!BN_nnmod(group->b, b, p, ctx))
174 goto err;
175 if (group->meth->field_encode)
176 if (!group->meth->field_encode(group, group->b, group->b, ctx))
177 goto err;
178
179 /* group->a_is_minus3 */
180 if (!BN_add_word(tmp_a, 3))
181 goto err;
182 group->a_is_minus3 = (0 == BN_cmp(tmp_a, group->field));
183
184 ret = 1;
60428dbf
BM		 185
186 err:
0f113f3e 187 BN_CTX_end(ctx);
23a1d5e9 188 BN_CTX_free(new_ctx);
0f113f3e
MC		 189 return ret;
190}
191
192int ec_GFp_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
193 BIGNUM *b, BN_CTX *ctx)
194{
195 int ret = 0;
196 BN_CTX *new_ctx = NULL;
197
198 if (p != NULL) {
199 if (!BN_copy(p, group->field))
200 return 0;
201 }
202
203 if (a != NULL || b != NULL) {
204 if (group->meth->field_decode) {
205 if (ctx == NULL) {
206 ctx = new_ctx = BN_CTX_new();
207 if (ctx == NULL)
208 return 0;
209 }
210 if (a != NULL) {
211 if (!group->meth->field_decode(group, a, group->a, ctx))
212 goto err;
213 }
214 if (b != NULL) {
215 if (!group->meth->field_decode(group, b, group->b, ctx))
216 goto err;
217 }
218 } else {
219 if (a != NULL) {
220 if (!BN_copy(a, group->a))
221 goto err;
222 }
223 if (b != NULL) {
224 if (!BN_copy(b, group->b))
225 goto err;
226 }
227 }
228 }
229
230 ret = 1;
60428dbf 231
0f113f3e 232 err:
23a1d5e9 233 BN_CTX_free(new_ctx);
0f113f3e
MC		 234 return ret;
235}
60428dbf 236
7793f30e 237int ec_GFp_simple_group_get_degree(const EC_GROUP *group)
0f113f3e
MC		 238{
239 return BN_num_bits(group->field);
240}
7793f30e 241
17d6bb81 242int ec_GFp_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
0f113f3e
MC		 243{
244 int ret = 0;
245 BIGNUM *a, *b, *order, *tmp_1, *tmp_2;
246 const BIGNUM *p = group->field;
247 BN_CTX *new_ctx = NULL;
248
249 if (ctx == NULL) {
250 ctx = new_ctx = BN_CTX_new();
251 if (ctx == NULL) {
252 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT,
253 ERR_R_MALLOC_FAILURE);
254 goto err;
255 }
256 }
257 BN_CTX_start(ctx);
258 a = BN_CTX_get(ctx);
259 b = BN_CTX_get(ctx);
260 tmp_1 = BN_CTX_get(ctx);
261 tmp_2 = BN_CTX_get(ctx);
262 order = BN_CTX_get(ctx);
263 if (order == NULL)
264 goto err;
265
266 if (group->meth->field_decode) {
267 if (!group->meth->field_decode(group, a, group->a, ctx))
268 goto err;
269 if (!group->meth->field_decode(group, b, group->b, ctx))
270 goto err;
271 } else {
272 if (!BN_copy(a, group->a))
273 goto err;
274 if (!BN_copy(b, group->b))
275 goto err;
276 }
277
50e735f9
MC		 278 /*-
279 * check the discriminant:
280 * y^2 = x^3 + a*x + b is an elliptic curve <=> 4*a^3 + 27*b^2 != 0 (mod p)
281 * 0 =< a, b < p
282 */
0f113f3e
MC		 283 if (BN_is_zero(a)) {
284 if (BN_is_zero(b))
285 goto err;
286 } else if (!BN_is_zero(b)) {
287 if (!BN_mod_sqr(tmp_1, a, p, ctx))
288 goto err;
289 if (!BN_mod_mul(tmp_2, tmp_1, a, p, ctx))
290 goto err;
291 if (!BN_lshift(tmp_1, tmp_2, 2))
292 goto err;
293 /* tmp_1 = 4*a^3 */
294
295 if (!BN_mod_sqr(tmp_2, b, p, ctx))
296 goto err;
297 if (!BN_mul_word(tmp_2, 27))
298 goto err;
299 /* tmp_2 = 27*b^2 */
300
301 if (!BN_mod_add(a, tmp_1, tmp_2, p, ctx))
302 goto err;
303 if (BN_is_zero(a))
304 goto err;
305 }
306 ret = 1;
af28dd6c 307
0f113f3e
MC		 308 err:
309 if (ctx != NULL)
310 BN_CTX_end(ctx);
23a1d5e9 311 BN_CTX_free(new_ctx);
0f113f3e
MC		 312 return ret;
313}
af28dd6c 314
60428dbf 315int ec_GFp_simple_point_init(EC_POINT *point)
0f113f3e
MC		 316{
317 point->X = BN_new();
318 point->Y = BN_new();
319 point->Z = BN_new();
320 point->Z_is_one = 0;
321
90945fa3 322 if (point->X == NULL || point->Y == NULL || point->Z == NULL) {
23a1d5e9
RS		 323 BN_free(point->X);
324 BN_free(point->Y);
325 BN_free(point->Z);
0f113f3e
MC		 326 return 0;
327 }
328 return 1;
329}
60428dbf
BM		 330
331void ec_GFp_simple_point_finish(EC_POINT *point)
0f113f3e
MC		 332{
333 BN_free(point->X);
334 BN_free(point->Y);
335 BN_free(point->Z);
336}
60428dbf
BM		 337
338void ec_GFp_simple_point_clear_finish(EC_POINT *point)
0f113f3e
MC		 339{
340 BN_clear_free(point->X);
341 BN_clear_free(point->Y);
342 BN_clear_free(point->Z);
343 point->Z_is_one = 0;
344}
60428dbf
BM		 345
346int ec_GFp_simple_point_copy(EC_POINT *dest, const EC_POINT *src)
0f113f3e
MC		 347{
348 if (!BN_copy(dest->X, src->X))
349 return 0;
350 if (!BN_copy(dest->Y, src->Y))
351 return 0;
352 if (!BN_copy(dest->Z, src->Z))
353 return 0;
354 dest->Z_is_one = src->Z_is_one;
b14e6015 355 dest->curve_name = src->curve_name;
0f113f3e
MC		 356
357 return 1;
358}
359
360int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group,
361 EC_POINT *point)
362{
363 point->Z_is_one = 0;
364 BN_zero(point->Z);
365 return 1;
366}
367
368int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
369 EC_POINT *point,
370 const BIGNUM *x,
371 const BIGNUM *y,
372 const BIGNUM *z,
373 BN_CTX *ctx)
374{
375 BN_CTX *new_ctx = NULL;
376 int ret = 0;
377
378 if (ctx == NULL) {
379 ctx = new_ctx = BN_CTX_new();
380 if (ctx == NULL)
381 return 0;
382 }
383
384 if (x != NULL) {
385 if (!BN_nnmod(point->X, x, group->field, ctx))
386 goto err;
387 if (group->meth->field_encode) {
388 if (!group->meth->field_encode(group, point->X, point->X, ctx))
389 goto err;
390 }
391 }
392
393 if (y != NULL) {
394 if (!BN_nnmod(point->Y, y, group->field, ctx))
395 goto err;
396 if (group->meth->field_encode) {
397 if (!group->meth->field_encode(group, point->Y, point->Y, ctx))
398 goto err;
399 }
400 }
401
402 if (z != NULL) {
403 int Z_is_one;
404
405 if (!BN_nnmod(point->Z, z, group->field, ctx))
406 goto err;
407 Z_is_one = BN_is_one(point->Z);
408 if (group->meth->field_encode) {
409 if (Z_is_one && (group->meth->field_set_to_one != 0)) {
410 if (!group->meth->field_set_to_one(group, point->Z, ctx))
411 goto err;
412 } else {
413 if (!group->
414 meth->field_encode(group, point->Z, point->Z, ctx))
415 goto err;
416 }
417 }
418 point->Z_is_one = Z_is_one;
419 }
420
421 ret = 1;
422
bb62a8b0 423 err:
23a1d5e9 424 BN_CTX_free(new_ctx);
0f113f3e
MC		 425 return ret;
426}
427
428int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group,
429 const EC_POINT *point,
430 BIGNUM *x, BIGNUM *y,
431 BIGNUM *z, BN_CTX *ctx)
432{
433 BN_CTX *new_ctx = NULL;
434 int ret = 0;
435
436 if (group->meth->field_decode != 0) {
437 if (ctx == NULL) {
438 ctx = new_ctx = BN_CTX_new();
439 if (ctx == NULL)
440 return 0;
441 }
442
443 if (x != NULL) {
444 if (!group->meth->field_decode(group, x, point->X, ctx))
445 goto err;
446 }
447 if (y != NULL) {
448 if (!group->meth->field_decode(group, y, point->Y, ctx))
449 goto err;
450 }
451 if (z != NULL) {
452 if (!group->meth->field_decode(group, z, point->Z, ctx))
453 goto err;
454 }
455 } else {
456 if (x != NULL) {
457 if (!BN_copy(x, point->X))
458 goto err;
459 }
460 if (y != NULL) {
461 if (!BN_copy(y, point->Y))
462 goto err;
463 }
464 if (z != NULL) {
465 if (!BN_copy(z, point->Z))
466 goto err;
467 }
468 }
469
470 ret = 1;
bb62a8b0 471
226cc7de 472 err:
23a1d5e9 473 BN_CTX_free(new_ctx);
0f113f3e
MC		 474 return ret;
475}
476
477int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group,
478 EC_POINT *point,
479 const BIGNUM *x,
480 const BIGNUM *y, BN_CTX *ctx)
481{
482 if (x == NULL || y == NULL) {
483 /*
484 * unlike for projective coordinates, we do not tolerate this
485 */
486 ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES,
487 ERR_R_PASSED_NULL_PARAMETER);
488 return 0;
489 }
490
491 return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y,
492 BN_value_one(), ctx);
493}
494
495int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group,
496 const EC_POINT *point,
497 BIGNUM *x, BIGNUM *y,
498 BN_CTX *ctx)
499{
500 BN_CTX *new_ctx = NULL;
501 BIGNUM *Z, *Z_1, *Z_2, *Z_3;
502 const BIGNUM *Z_;
503 int ret = 0;
504
505 if (EC_POINT_is_at_infinity(group, point)) {
506 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
507 EC_R_POINT_AT_INFINITY);
508 return 0;
509 }
510
511 if (ctx == NULL) {
512 ctx = new_ctx = BN_CTX_new();
513 if (ctx == NULL)
514 return 0;
515 }
516
517 BN_CTX_start(ctx);
518 Z = BN_CTX_get(ctx);
519 Z_1 = BN_CTX_get(ctx);
520 Z_2 = BN_CTX_get(ctx);
521 Z_3 = BN_CTX_get(ctx);
522 if (Z_3 == NULL)
523 goto err;
524
525 /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
526
527 if (group->meth->field_decode) {
528 if (!group->meth->field_decode(group, Z, point->Z, ctx))
529 goto err;
530 Z_ = Z;
531 } else {
532 Z_ = point->Z;
533 }
534
535 if (BN_is_one(Z_)) {
536 if (group->meth->field_decode) {
537 if (x != NULL) {
538 if (!group->meth->field_decode(group, x, point->X, ctx))
539 goto err;
540 }
541 if (y != NULL) {
542 if (!group->meth->field_decode(group, y, point->Y, ctx))
543 goto err;
544 }
545 } else {
546 if (x != NULL) {
547 if (!BN_copy(x, point->X))
548 goto err;
549 }
550 if (y != NULL) {
551 if (!BN_copy(y, point->Y))
552 goto err;
553 }
554 }
555 } else {
556 if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) {
557 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
558 ERR_R_BN_LIB);
559 goto err;
560 }
561
562 if (group->meth->field_encode == 0) {
563 /* field_sqr works on standard representation */
564 if (!group->meth->field_sqr(group, Z_2, Z_1, ctx))
565 goto err;
566 } else {
567 if (!BN_mod_sqr(Z_2, Z_1, group->field, ctx))
568 goto err;
569 }
570
571 if (x != NULL) {
572 /*
573 * in the Montgomery case, field_mul will cancel out Montgomery
574 * factor in X:
575 */
576 if (!group->meth->field_mul(group, x, point->X, Z_2, ctx))
577 goto err;
578 }
579
580 if (y != NULL) {
581 if (group->meth->field_encode == 0) {
582 /*
583 * field_mul works on standard representation
584 */
585 if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx))
586 goto err;
587 } else {
588 if (!BN_mod_mul(Z_3, Z_2, Z_1, group->field, ctx))
589 goto err;
590 }
591
592 /*
593 * in the Montgomery case, field_mul will cancel out Montgomery
594 * factor in Y:
595 */
596 if (!group->meth->field_mul(group, y, point->Y, Z_3, ctx))
597 goto err;
598 }
599 }
600
601 ret = 1;
226cc7de
BM		 602
603 err:
0f113f3e 604 BN_CTX_end(ctx);
23a1d5e9 605 BN_CTX_free(new_ctx);
0f113f3e
MC		 606 return ret;
607}
608
609int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
610 const EC_POINT *b, BN_CTX *ctx)
611{
612 int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *,
613 const BIGNUM *, BN_CTX *);
614 int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
615 const BIGNUM *p;
616 BN_CTX *new_ctx = NULL;
617 BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6;
618 int ret = 0;
619
620 if (a == b)
621 return EC_POINT_dbl(group, r, a, ctx);
622 if (EC_POINT_is_at_infinity(group, a))
623 return EC_POINT_copy(r, b);
624 if (EC_POINT_is_at_infinity(group, b))
625 return EC_POINT_copy(r, a);
626
627 field_mul = group->meth->field_mul;
628 field_sqr = group->meth->field_sqr;
629 p = group->field;
630
631 if (ctx == NULL) {
632 ctx = new_ctx = BN_CTX_new();
633 if (ctx == NULL)
634 return 0;
635 }
636
637 BN_CTX_start(ctx);
638 n0 = BN_CTX_get(ctx);
639 n1 = BN_CTX_get(ctx);
640 n2 = BN_CTX_get(ctx);
641 n3 = BN_CTX_get(ctx);
642 n4 = BN_CTX_get(ctx);
643 n5 = BN_CTX_get(ctx);
644 n6 = BN_CTX_get(ctx);
645 if (n6 == NULL)
646 goto end;
647
648 /*
649 * Note that in this function we must not read components of 'a' or 'b'
650 * once we have written the corresponding components of 'r'. ('r' might
651 * be one of 'a' or 'b'.)
652 */
653
654 /* n1, n2 */
655 if (b->Z_is_one) {
656 if (!BN_copy(n1, a->X))
657 goto end;
658 if (!BN_copy(n2, a->Y))
659 goto end;
660 /* n1 = X_a */
661 /* n2 = Y_a */
662 } else {
663 if (!field_sqr(group, n0, b->Z, ctx))
664 goto end;
665 if (!field_mul(group, n1, a->X, n0, ctx))
666 goto end;
667 /* n1 = X_a * Z_b^2 */
668
669 if (!field_mul(group, n0, n0, b->Z, ctx))
670 goto end;
671 if (!field_mul(group, n2, a->Y, n0, ctx))
672 goto end;
673 /* n2 = Y_a * Z_b^3 */
674 }
675
676 /* n3, n4 */
677 if (a->Z_is_one) {
678 if (!BN_copy(n3, b->X))
679 goto end;
680 if (!BN_copy(n4, b->Y))
681 goto end;
682 /* n3 = X_b */
683 /* n4 = Y_b */
684 } else {
685 if (!field_sqr(group, n0, a->Z, ctx))
686 goto end;
687 if (!field_mul(group, n3, b->X, n0, ctx))
688 goto end;
689 /* n3 = X_b * Z_a^2 */
690
691 if (!field_mul(group, n0, n0, a->Z, ctx))
692 goto end;
693 if (!field_mul(group, n4, b->Y, n0, ctx))
694 goto end;
695 /* n4 = Y_b * Z_a^3 */
696 }
697
698 /* n5, n6 */
699 if (!BN_mod_sub_quick(n5, n1, n3, p))
700 goto end;
701 if (!BN_mod_sub_quick(n6, n2, n4, p))
702 goto end;
703 /* n5 = n1 - n3 */
704 /* n6 = n2 - n4 */
705
706 if (BN_is_zero(n5)) {
707 if (BN_is_zero(n6)) {
708 /* a is the same point as b */
709 BN_CTX_end(ctx);
710 ret = EC_POINT_dbl(group, r, a, ctx);
711 ctx = NULL;
712 goto end;
713 } else {
714 /* a is the inverse of b */
715 BN_zero(r->Z);
716 r->Z_is_one = 0;
717 ret = 1;
718 goto end;
719 }
720 }
721
722 /* 'n7', 'n8' */
723 if (!BN_mod_add_quick(n1, n1, n3, p))
724 goto end;
725 if (!BN_mod_add_quick(n2, n2, n4, p))
726 goto end;
727 /* 'n7' = n1 + n3 */
728 /* 'n8' = n2 + n4 */
729
730 /* Z_r */
731 if (a->Z_is_one && b->Z_is_one) {
732 if (!BN_copy(r->Z, n5))
733 goto end;
734 } else {
735 if (a->Z_is_one) {
736 if (!BN_copy(n0, b->Z))
737 goto end;
738 } else if (b->Z_is_one) {
739 if (!BN_copy(n0, a->Z))
740 goto end;
741 } else {
742 if (!field_mul(group, n0, a->Z, b->Z, ctx))
743 goto end;
744 }
745 if (!field_mul(group, r->Z, n0, n5, ctx))
746 goto end;
747 }
748 r->Z_is_one = 0;
749 /* Z_r = Z_a * Z_b * n5 */
750
751 /* X_r */
752 if (!field_sqr(group, n0, n6, ctx))
753 goto end;
754 if (!field_sqr(group, n4, n5, ctx))
755 goto end;
756 if (!field_mul(group, n3, n1, n4, ctx))
757 goto end;
758 if (!BN_mod_sub_quick(r->X, n0, n3, p))
759 goto end;
760 /* X_r = n6^2 - n5^2 * 'n7' */
761
762 /* 'n9' */
763 if (!BN_mod_lshift1_quick(n0, r->X, p))
764 goto end;
765 if (!BN_mod_sub_quick(n0, n3, n0, p))
766 goto end;
767 /* n9 = n5^2 * 'n7' - 2 * X_r */
768
769 /* Y_r */
770 if (!field_mul(group, n0, n0, n6, ctx))
771 goto end;
772 if (!field_mul(group, n5, n4, n5, ctx))
773 goto end; /* now n5 is n5^3 */
774 if (!field_mul(group, n1, n2, n5, ctx))
775 goto end;
776 if (!BN_mod_sub_quick(n0, n0, n1, p))
777 goto end;
778 if (BN_is_odd(n0))
779 if (!BN_add(n0, n0, p))
780 goto end;
781 /* now 0 <= n0 < 2*p, and n0 is even */
782 if (!BN_rshift1(r->Y, n0))
783 goto end;
784 /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */
785
786 ret = 1;
60428dbf
BM		 787
788 end:
0f113f3e
MC		 789 if (ctx) /* otherwise we already called BN_CTX_end */
790 BN_CTX_end(ctx);
23a1d5e9 791 BN_CTX_free(new_ctx);
0f113f3e
MC		 792 return ret;
793}
794
795int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
796 BN_CTX *ctx)
797{
798 int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *,
799 const BIGNUM *, BN_CTX *);
800 int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
801 const BIGNUM *p;
802 BN_CTX *new_ctx = NULL;
803 BIGNUM *n0, *n1, *n2, *n3;
804 int ret = 0;
805
806 if (EC_POINT_is_at_infinity(group, a)) {
807 BN_zero(r->Z);
808 r->Z_is_one = 0;
809 return 1;
810 }
811
812 field_mul = group->meth->field_mul;
813 field_sqr = group->meth->field_sqr;
814 p = group->field;
815
816 if (ctx == NULL) {
817 ctx = new_ctx = BN_CTX_new();
818 if (ctx == NULL)
819 return 0;
820 }
821
822 BN_CTX_start(ctx);
823 n0 = BN_CTX_get(ctx);
824 n1 = BN_CTX_get(ctx);
825 n2 = BN_CTX_get(ctx);
826 n3 = BN_CTX_get(ctx);
827 if (n3 == NULL)
828 goto err;
829
830 /*
831 * Note that in this function we must not read components of 'a' once we
832 * have written the corresponding components of 'r'. ('r' might the same
833 * as 'a'.)
834 */
835
836 /* n1 */
837 if (a->Z_is_one) {
838 if (!field_sqr(group, n0, a->X, ctx))
839 goto err;
840 if (!BN_mod_lshift1_quick(n1, n0, p))
841 goto err;
842 if (!BN_mod_add_quick(n0, n0, n1, p))
843 goto err;
844 if (!BN_mod_add_quick(n1, n0, group->a, p))
845 goto err;
846 /* n1 = 3 * X_a^2 + a_curve */
847 } else if (group->a_is_minus3) {
848 if (!field_sqr(group, n1, a->Z, ctx))
849 goto err;
850 if (!BN_mod_add_quick(n0, a->X, n1, p))
851 goto err;
852 if (!BN_mod_sub_quick(n2, a->X, n1, p))
853 goto err;
854 if (!field_mul(group, n1, n0, n2, ctx))
855 goto err;
856 if (!BN_mod_lshift1_quick(n0, n1, p))
857 goto err;
858 if (!BN_mod_add_quick(n1, n0, n1, p))
859 goto err;
35a1cc90
MC		 860 /*-
861 * n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2)
862 * = 3 * X_a^2 - 3 * Z_a^4
863 */
0f113f3e
MC		 864 } else {
865 if (!field_sqr(group, n0, a->X, ctx))
866 goto err;
867 if (!BN_mod_lshift1_quick(n1, n0, p))
868 goto err;
869 if (!BN_mod_add_quick(n0, n0, n1, p))
870 goto err;
871 if (!field_sqr(group, n1, a->Z, ctx))
872 goto err;
873 if (!field_sqr(group, n1, n1, ctx))
874 goto err;
875 if (!field_mul(group, n1, n1, group->a, ctx))
876 goto err;
877 if (!BN_mod_add_quick(n1, n1, n0, p))
878 goto err;
879 /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */
880 }
881
882 /* Z_r */
883 if (a->Z_is_one) {
884 if (!BN_copy(n0, a->Y))
885 goto err;
886 } else {
887 if (!field_mul(group, n0, a->Y, a->Z, ctx))
888 goto err;
889 }
890 if (!BN_mod_lshift1_quick(r->Z, n0, p))
891 goto err;
892 r->Z_is_one = 0;
893 /* Z_r = 2 * Y_a * Z_a */
894
895 /* n2 */
896 if (!field_sqr(group, n3, a->Y, ctx))
897 goto err;
898 if (!field_mul(group, n2, a->X, n3, ctx))
899 goto err;
900 if (!BN_mod_lshift_quick(n2, n2, 2, p))
901 goto err;
902 /* n2 = 4 * X_a * Y_a^2 */
903
904 /* X_r */
905 if (!BN_mod_lshift1_quick(n0, n2, p))
906 goto err;
907 if (!field_sqr(group, r->X, n1, ctx))
908 goto err;
909 if (!BN_mod_sub_quick(r->X, r->X, n0, p))
910 goto err;
911 /* X_r = n1^2 - 2 * n2 */
912
913 /* n3 */
914 if (!field_sqr(group, n0, n3, ctx))
915 goto err;
916 if (!BN_mod_lshift_quick(n3, n0, 3, p))
917 goto err;
918 /* n3 = 8 * Y_a^4 */
919
920 /* Y_r */
921 if (!BN_mod_sub_quick(n0, n2, r->X, p))
922 goto err;
923 if (!field_mul(group, n0, n1, n0, ctx))
924 goto err;
925 if (!BN_mod_sub_quick(r->Y, n0, n3, p))
926 goto err;
927 /* Y_r = n1 * (n2 - X_r) - n3 */
928
929 ret = 1;
60428dbf
BM		 930
931 err:
0f113f3e 932 BN_CTX_end(ctx);
23a1d5e9 933 BN_CTX_free(new_ctx);
0f113f3e
MC		 934 return ret;
935}
60428dbf 936
bb62a8b0 937int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
0f113f3e
MC		 938{
939 if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(point->Y))
940 /* point is its own inverse */
941 return 1;
1d5bd6cf 942
0f113f3e
MC		 943 return BN_usub(point->Y, group->field, point->Y);
944}
1d5bd6cf 945
60428dbf 946int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
0f113f3e
MC		 947{
948 return BN_is_zero(point->Z);
949}
950
951int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point,
952 BN_CTX *ctx)
953{
954 int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *,
955 const BIGNUM *, BN_CTX *);
956 int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
957 const BIGNUM *p;
958 BN_CTX *new_ctx = NULL;
959 BIGNUM *rh, *tmp, *Z4, *Z6;
960 int ret = -1;
961
962 if (EC_POINT_is_at_infinity(group, point))
963 return 1;
964
965 field_mul = group->meth->field_mul;
966 field_sqr = group->meth->field_sqr;
967 p = group->field;
968
969 if (ctx == NULL) {
970 ctx = new_ctx = BN_CTX_new();
971 if (ctx == NULL)
972 return -1;
973 }
974
975 BN_CTX_start(ctx);
976 rh = BN_CTX_get(ctx);
977 tmp = BN_CTX_get(ctx);
978 Z4 = BN_CTX_get(ctx);
979 Z6 = BN_CTX_get(ctx);
980 if (Z6 == NULL)
981 goto err;
982
35a1cc90
MC		 983 /*-
984 * We have a curve defined by a Weierstrass equation
985 * y^2 = x^3 + a*x + b.
986 * The point to consider is given in Jacobian projective coordinates
987 * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3).
988 * Substituting this and multiplying by Z^6 transforms the above equation into
989 * Y^2 = X^3 + a*X*Z^4 + b*Z^6.
990 * To test this, we add up the right-hand side in 'rh'.
991 */
0f113f3e
MC		 992
993 /* rh := X^2 */
994 if (!field_sqr(group, rh, point->X, ctx))
995 goto err;
996
997 if (!point->Z_is_one) {
998 if (!field_sqr(group, tmp, point->Z, ctx))
999 goto err;
1000 if (!field_sqr(group, Z4, tmp, ctx))
1001 goto err;
1002 if (!field_mul(group, Z6, Z4, tmp, ctx))
1003 goto err;
1004
1005 /* rh := (rh + a*Z^4)*X */
1006 if (group->a_is_minus3) {
1007 if (!BN_mod_lshift1_quick(tmp, Z4, p))
1008 goto err;
1009 if (!BN_mod_add_quick(tmp, tmp, Z4, p))
1010 goto err;
1011 if (!BN_mod_sub_quick(rh, rh, tmp, p))
1012 goto err;
1013 if (!field_mul(group, rh, rh, point->X, ctx))
1014 goto err;
1015 } else {
1016 if (!field_mul(group, tmp, Z4, group->a, ctx))
1017 goto err;
1018 if (!BN_mod_add_quick(rh, rh, tmp, p))
1019 goto err;
1020 if (!field_mul(group, rh, rh, point->X, ctx))
1021 goto err;
1022 }
1023
1024 /* rh := rh + b*Z^6 */
1025 if (!field_mul(group, tmp, group->b, Z6, ctx))
1026 goto err;
1027 if (!BN_mod_add_quick(rh, rh, tmp, p))
1028 goto err;
1029 } else {
1030 /* point->Z_is_one */
1031
1032 /* rh := (rh + a)*X */
1033 if (!BN_mod_add_quick(rh, rh, group->a, p))
1034 goto err;
1035 if (!field_mul(group, rh, rh, point->X, ctx))
1036 goto err;
1037 /* rh := rh + b */
1038 if (!BN_mod_add_quick(rh, rh, group->b, p))
1039 goto err;
1040 }
1041
1042 /* 'lh' := Y^2 */
1043 if (!field_sqr(group, tmp, point->Y, ctx))
1044 goto err;
1045
1046 ret = (0 == BN_ucmp(tmp, rh));
e869d4bd
BM		 1047
1048 err:
0f113f3e 1049 BN_CTX_end(ctx);
23a1d5e9 1050 BN_CTX_free(new_ctx);
0f113f3e
MC		 1051 return ret;
1052}
1053
1054int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a,
1055 const EC_POINT *b, BN_CTX *ctx)
1056{
35a1cc90
MC		 1057 /*-
1058 * return values:
1059 * -1 error
1060 * 0 equal (in affine coordinates)
1061 * 1 not equal
1062 */
0f113f3e
MC		 1063
1064 int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *,
1065 const BIGNUM *, BN_CTX *);
1066 int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
1067 BN_CTX *new_ctx = NULL;
1068 BIGNUM *tmp1, *tmp2, *Za23, *Zb23;
1069 const BIGNUM *tmp1_, *tmp2_;
1070 int ret = -1;
1071
1072 if (EC_POINT_is_at_infinity(group, a)) {
1073 return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
1074 }
1075
1076 if (EC_POINT_is_at_infinity(group, b))
1077 return 1;
1078
1079 if (a->Z_is_one && b->Z_is_one) {
1080 return ((BN_cmp(a->X, b->X) == 0) && BN_cmp(a->Y, b->Y) == 0) ? 0 : 1;
1081 }
1082
1083 field_mul = group->meth->field_mul;
1084 field_sqr = group->meth->field_sqr;
1085
1086 if (ctx == NULL) {
1087 ctx = new_ctx = BN_CTX_new();
1088 if (ctx == NULL)
1089 return -1;
1090 }
1091
1092 BN_CTX_start(ctx);
1093 tmp1 = BN_CTX_get(ctx);
1094 tmp2 = BN_CTX_get(ctx);
1095 Za23 = BN_CTX_get(ctx);
1096 Zb23 = BN_CTX_get(ctx);
1097 if (Zb23 == NULL)
1098 goto end;
1099
35a1cc90
MC		 1100 /*-
1101 * We have to decide whether
1102 * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3),
1103 * or equivalently, whether
1104 * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3).
1105 */
0f113f3e
MC		 1106
1107 if (!b->Z_is_one) {
1108 if (!field_sqr(group, Zb23, b->Z, ctx))
1109 goto end;
1110 if (!field_mul(group, tmp1, a->X, Zb23, ctx))
1111 goto end;
1112 tmp1_ = tmp1;
1113 } else
1114 tmp1_ = a->X;
1115 if (!a->Z_is_one) {
1116 if (!field_sqr(group, Za23, a->Z, ctx))
1117 goto end;
1118 if (!field_mul(group, tmp2, b->X, Za23, ctx))
1119 goto end;
1120 tmp2_ = tmp2;
1121 } else
1122 tmp2_ = b->X;
1123
1124 /* compare X_a*Z_b^2 with X_b*Z_a^2 */
1125 if (BN_cmp(tmp1_, tmp2_) != 0) {
1126 ret = 1; /* points differ */
1127 goto end;
1128 }
1129
1130 if (!b->Z_is_one) {
1131 if (!field_mul(group, Zb23, Zb23, b->Z, ctx))
1132 goto end;
1133 if (!field_mul(group, tmp1, a->Y, Zb23, ctx))
1134 goto end;
1135 /* tmp1_ = tmp1 */
1136 } else
1137 tmp1_ = a->Y;
1138 if (!a->Z_is_one) {
1139 if (!field_mul(group, Za23, Za23, a->Z, ctx))
1140 goto end;
1141 if (!field_mul(group, tmp2, b->Y, Za23, ctx))
1142 goto end;
1143 /* tmp2_ = tmp2 */
1144 } else
1145 tmp2_ = b->Y;
1146
1147 /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */
1148 if (BN_cmp(tmp1_, tmp2_) != 0) {
1149 ret = 1; /* points differ */
1150 goto end;
1151 }
1152
1153 /* points are equal */
1154 ret = 0;
bb62a8b0
BM		 1155
1156 end:
0f113f3e 1157 BN_CTX_end(ctx);
23a1d5e9 1158 BN_CTX_free(new_ctx);
0f113f3e
MC		 1159 return ret;
1160}
1161
1162int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point,
1163 BN_CTX *ctx)
1164{
1165 BN_CTX *new_ctx = NULL;
1166 BIGNUM *x, *y;
1167 int ret = 0;
1168
1169 if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))
1170 return 1;
1171
1172 if (ctx == NULL) {
1173 ctx = new_ctx = BN_CTX_new();
1174 if (ctx == NULL)
1175 return 0;
1176 }
1177
1178 BN_CTX_start(ctx);
1179 x = BN_CTX_get(ctx);
1180 y = BN_CTX_get(ctx);
1181 if (y == NULL)
1182 goto err;
1183
1184 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
1185 goto err;
1186 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
1187 goto err;
1188 if (!point->Z_is_one) {
1189 ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR);
1190 goto err;
1191 }
1192
1193 ret = 1;
e869d4bd 1194
226cc7de 1195 err:
0f113f3e 1196 BN_CTX_end(ctx);
23a1d5e9 1197 BN_CTX_free(new_ctx);
0f113f3e
MC		 1198 return ret;
1199}
1200
1201int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num,
1202 EC_POINT *points[], BN_CTX *ctx)
1203{
1204 BN_CTX *new_ctx = NULL;
1205 BIGNUM *tmp, *tmp_Z;
1206 BIGNUM **prod_Z = NULL;
1207 size_t i;
1208 int ret = 0;
1209
1210 if (num == 0)
1211 return 1;
1212
1213 if (ctx == NULL) {
1214 ctx = new_ctx = BN_CTX_new();
1215 if (ctx == NULL)
1216 return 0;
1217 }
1218
1219 BN_CTX_start(ctx);
1220 tmp = BN_CTX_get(ctx);
1221 tmp_Z = BN_CTX_get(ctx);
edea42c6 1222 if (tmp_Z == NULL)
0f113f3e
MC		 1223 goto err;
1224
cbe29648 1225 prod_Z = OPENSSL_malloc(num * sizeof(prod_Z[0]));
0f113f3e
MC		 1226 if (prod_Z == NULL)
1227 goto err;
1228 for (i = 0; i < num; i++) {
1229 prod_Z[i] = BN_new();
1230 if (prod_Z[i] == NULL)
1231 goto err;
1232 }
1233
1234 /*
1235 * Set each prod_Z[i] to the product of points[0]->Z .. points[i]->Z,
1236 * skipping any zero-valued inputs (pretend that they're 1).
1237 */
1238
1239 if (!BN_is_zero(points[0]->Z)) {
1240 if (!BN_copy(prod_Z[0], points[0]->Z))
1241 goto err;
1242 } else {
1243 if (group->meth->field_set_to_one != 0) {
1244 if (!group->meth->field_set_to_one(group, prod_Z[0], ctx))
1245 goto err;
1246 } else {
1247 if (!BN_one(prod_Z[0]))
1248 goto err;
1249 }
1250 }
1251
1252 for (i = 1; i < num; i++) {
1253 if (!BN_is_zero(points[i]->Z)) {
1254 if (!group->
1255 meth->field_mul(group, prod_Z[i], prod_Z[i - 1], points[i]->Z,
1256 ctx))
1257 goto err;
1258 } else {
1259 if (!BN_copy(prod_Z[i], prod_Z[i - 1]))
1260 goto err;
1261 }
1262 }
1263
1264 /*
1265 * Now use a single explicit inversion to replace every non-zero
1266 * points[i]->Z by its inverse.
1267 */
1268
1269 if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) {
1270 ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
1271 goto err;
1272 }
1273 if (group->meth->field_encode != 0) {
1274 /*
1275 * In the Montgomery case, we just turned R*H (representing H) into
1276 * 1/(R*H), but we need R*(1/H) (representing 1/H); i.e. we need to
1277 * multiply by the Montgomery factor twice.
1278 */
1279 if (!group->meth->field_encode(group, tmp, tmp, ctx))
1280 goto err;
1281 if (!group->meth->field_encode(group, tmp, tmp, ctx))
1282 goto err;
1283 }
1284
1285 for (i = num - 1; i > 0; --i) {
1286 /*
1287 * Loop invariant: tmp is the product of the inverses of points[0]->Z
1288 * .. points[i]->Z (zero-valued inputs skipped).
1289 */
1290 if (!BN_is_zero(points[i]->Z)) {
1291 /*
1292 * Set tmp_Z to the inverse of points[i]->Z (as product of Z
1293 * inverses 0 .. i, Z values 0 .. i - 1).
1294 */
1295 if (!group->
1296 meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx))
1297 goto err;
1298 /*
1299 * Update tmp to satisfy the loop invariant for i - 1.
1300 */
1301 if (!group->meth->field_mul(group, tmp, tmp, points[i]->Z, ctx))
1302 goto err;
1303 /* Replace points[i]->Z by its inverse. */
1304 if (!BN_copy(points[i]->Z, tmp_Z))
1305 goto err;
1306 }
1307 }
1308
1309 if (!BN_is_zero(points[0]->Z)) {
1310 /* Replace points[0]->Z by its inverse. */
1311 if (!BN_copy(points[0]->Z, tmp))
1312 goto err;
1313 }
1314
1315 /* Finally, fix up the X and Y coordinates for all points. */
1316
1317 for (i = 0; i < num; i++) {
1318 EC_POINT *p = points[i];
1319
1320 if (!BN_is_zero(p->Z)) {
1321 /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */
1322
1323 if (!group->meth->field_sqr(group, tmp, p->Z, ctx))
1324 goto err;
1325 if (!group->meth->field_mul(group, p->X, p->X, tmp, ctx))
1326 goto err;
1327
1328 if (!group->meth->field_mul(group, tmp, tmp, p->Z, ctx))
1329 goto err;
1330 if (!group->meth->field_mul(group, p->Y, p->Y, tmp, ctx))
1331 goto err;
1332
1333 if (group->meth->field_set_to_one != 0) {
1334 if (!group->meth->field_set_to_one(group, p->Z, ctx))
1335 goto err;
1336 } else {
1337 if (!BN_one(p->Z))
1338 goto err;
1339 }
1340 p->Z_is_one = 1;
1341 }
1342 }
1343
1344 ret = 1;
0fe73d6c 1345
48fe4d62 1346 err:
0f113f3e 1347 BN_CTX_end(ctx);
23a1d5e9 1348 BN_CTX_free(new_ctx);
0f113f3e
MC		 1349 if (prod_Z != NULL) {
1350 for (i = 0; i < num; i++) {
1351 if (prod_Z[i] == NULL)
1352 break;
1353 BN_clear_free(prod_Z[i]);
1354 }
1355 OPENSSL_free(prod_Z);
1356 }
1357 return ret;
1358}
1359
1360int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
1361 const BIGNUM *b, BN_CTX *ctx)
1362{
1363 return BN_mod_mul(r, a, b, group->field, ctx);
1364}
1365
1366int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
1367 BN_CTX *ctx)
1368{
1369 return BN_mod_sqr(r, a, group->field, ctx);
1370}
f667820c
SH		 1371
1372/*-
1373 * Apply randomization of EC point projective coordinates:
1374 *
1375 * (X, Y ,Z ) = (lambda^2*X, lambda^3*Y, lambda*Z)
1376 * lambda = [1,group->field)
1377 *
1378 */
1379int ec_GFp_simple_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
1380 BN_CTX *ctx)
1381{
1382 int ret = 0;
1383 BIGNUM *lambda = NULL;
1384 BIGNUM *temp = NULL;
1385
1386 BN_CTX_start(ctx);
1387 lambda = BN_CTX_get(ctx);
1388 temp = BN_CTX_get(ctx);
1389 if (temp == NULL) {
1390 ECerr(EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES, ERR_R_MALLOC_FAILURE);
1391 goto err;
1392 }
1393
1394 /* make sure lambda is not zero */
1395 do {
1396 if (!BN_priv_rand_range(lambda, group->field)) {
1397 ECerr(EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES, ERR_R_BN_LIB);
1398 goto err;
1399 }
1400 } while (BN_is_zero(lambda));
1401
1402 /* if field_encode defined convert between representations */
1403 if (group->meth->field_encode != NULL
1404 && !group->meth->field_encode(group, lambda, lambda, ctx))
1405 goto err;
1406 if (!group->meth->field_mul(group, p->Z, p->Z, lambda, ctx))
1407 goto err;
1408 if (!group->meth->field_sqr(group, temp, lambda, ctx))
1409 goto err;
1410 if (!group->meth->field_mul(group, p->X, p->X, temp, ctx))
1411 goto err;
1412 if (!group->meth->field_mul(group, temp, temp, lambda, ctx))
1413 goto err;
1414 if (!group->meth->field_mul(group, p->Y, p->Y, temp, ctx))
1415 goto err;
1416 p->Z_is_one = 0;
1417
1418 ret = 1;
1419
1420 err:
1421 BN_CTX_end(ctx);
1422 return ret;
1423}
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