1 /* crypto/ec/ecp_smpl.c */
2 /* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
3 * for the OpenSSL project.
4 * Includes code written by Bodo Moeller for the OpenSSL project.
6 /* ====================================================================
7 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * openssl-core@openssl.org.
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
35 * 6. Redistributions of any form whatsoever must retain the following
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
59 /* ====================================================================
60 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
61 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
62 * and contributed to the OpenSSL project.
65 #include <openssl/err.h>
66 #include <openssl/symhacks.h>
70 const EC_METHOD *EC_GFp_simple_method(void)
72 static const EC_METHOD ret = {
73 NID_X9_62_prime_field,
74 ec_GFp_simple_group_init,
75 ec_GFp_simple_group_finish,
76 ec_GFp_simple_group_clear_finish,
77 ec_GFp_simple_group_copy,
78 ec_GFp_simple_group_set_curve,
79 ec_GFp_simple_group_get_curve,
80 ec_GFp_simple_group_get_degree,
81 ec_GFp_simple_group_check_discriminant,
82 ec_GFp_simple_point_init,
83 ec_GFp_simple_point_finish,
84 ec_GFp_simple_point_clear_finish,
85 ec_GFp_simple_point_copy,
86 ec_GFp_simple_point_set_to_infinity,
87 ec_GFp_simple_set_Jprojective_coordinates_GFp,
88 ec_GFp_simple_get_Jprojective_coordinates_GFp,
89 ec_GFp_simple_point_set_affine_coordinates,
90 ec_GFp_simple_point_get_affine_coordinates,
91 ec_GFp_simple_set_compressed_coordinates,
92 ec_GFp_simple_point2oct,
93 ec_GFp_simple_oct2point,
97 ec_GFp_simple_is_at_infinity,
98 ec_GFp_simple_is_on_curve,
100 ec_GFp_simple_make_affine,
101 ec_GFp_simple_points_make_affine,
103 0 /* precompute_mult */,
104 0 /* have_precompute_mult */,
105 ec_GFp_simple_field_mul,
106 ec_GFp_simple_field_sqr,
108 0 /* field_encode */,
109 0 /* field_decode */,
110 0 /* field_set_to_one */ };
116 /* Most method functions in this file are designed to work with
117 * non-trivial representations of field elements if necessary
118 * (see ecp_mont.c): while standard modular addition and subtraction
119 * are used, the field_mul and field_sqr methods will be used for
120 * multiplication, and field_encode and field_decode (if defined)
121 * will be used for converting between representations.
123 * Functions ec_GFp_simple_points_make_affine() and
124 * ec_GFp_simple_point_get_affine_coordinates() specifically assume
125 * that if a non-trivial representation is used, it is a Montgomery
126 * representation (i.e. 'encoding' means multiplying by some factor R).
130 int ec_GFp_simple_group_init(EC_GROUP *group)
132 BN_init(&group->field);
135 group->a_is_minus3 = 0;
140 void ec_GFp_simple_group_finish(EC_GROUP *group)
142 BN_free(&group->field);
148 void ec_GFp_simple_group_clear_finish(EC_GROUP *group)
150 BN_clear_free(&group->field);
151 BN_clear_free(&group->a);
152 BN_clear_free(&group->b);
156 int ec_GFp_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src)
158 if (!BN_copy(&dest->field, &src->field)) return 0;
159 if (!BN_copy(&dest->a, &src->a)) return 0;
160 if (!BN_copy(&dest->b, &src->b)) return 0;
162 dest->a_is_minus3 = src->a_is_minus3;
168 int ec_GFp_simple_group_set_curve(EC_GROUP *group,
169 const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
172 BN_CTX *new_ctx = NULL;
175 /* p must be a prime > 3 */
176 if (BN_num_bits(p) <= 2 || !BN_is_odd(p))
178 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE, EC_R_INVALID_FIELD);
184 ctx = new_ctx = BN_CTX_new();
190 tmp_a = BN_CTX_get(ctx);
191 if (tmp_a == NULL) goto err;
194 if (!BN_copy(&group->field, p)) goto err;
195 BN_set_negative(&group->field, 0);
198 if (!BN_nnmod(tmp_a, a, p, ctx)) goto err;
199 if (group->meth->field_encode)
200 { if (!group->meth->field_encode(group, &group->a, tmp_a, ctx)) goto err; }
202 if (!BN_copy(&group->a, tmp_a)) goto err;
205 if (!BN_nnmod(&group->b, b, p, ctx)) goto err;
206 if (group->meth->field_encode)
207 if (!group->meth->field_encode(group, &group->b, &group->b, ctx)) goto err;
209 /* group->a_is_minus3 */
210 if (!BN_add_word(tmp_a, 3)) goto err;
211 group->a_is_minus3 = (0 == BN_cmp(tmp_a, &group->field));
218 BN_CTX_free(new_ctx);
223 int ec_GFp_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)
226 BN_CTX *new_ctx = NULL;
230 if (!BN_copy(p, &group->field)) return 0;
233 if (a != NULL || b != NULL)
235 if (group->meth->field_decode)
239 ctx = new_ctx = BN_CTX_new();
245 if (!group->meth->field_decode(group, a, &group->a, ctx)) goto err;
249 if (!group->meth->field_decode(group, b, &group->b, ctx)) goto err;
256 if (!BN_copy(a, &group->a)) goto err;
260 if (!BN_copy(b, &group->b)) goto err;
269 BN_CTX_free(new_ctx);
274 int ec_GFp_simple_group_get_degree(const EC_GROUP *group)
276 return BN_num_bits(&group->field);
280 int ec_GFp_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
283 BIGNUM *a,*b,*order,*tmp_1,*tmp_2;
284 const BIGNUM *p = &group->field;
285 BN_CTX *new_ctx = NULL;
289 ctx = new_ctx = BN_CTX_new();
292 ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT, ERR_R_MALLOC_FAILURE);
299 tmp_1 = BN_CTX_get(ctx);
300 tmp_2 = BN_CTX_get(ctx);
301 order = BN_CTX_get(ctx);
302 if (order == NULL) goto err;
304 if (group->meth->field_decode)
306 if (!group->meth->field_decode(group, a, &group->a, ctx)) goto err;
307 if (!group->meth->field_decode(group, b, &group->b, ctx)) goto err;
311 if (!BN_copy(a, &group->a)) goto err;
312 if (!BN_copy(b, &group->b)) goto err;
316 * check the discriminant:
317 * y^2 = x^3 + a*x + b is an elliptic curve <=> 4*a^3 + 27*b^2 != 0 (mod p)
322 if (BN_is_zero(b)) goto err;
324 else if (!BN_is_zero(b))
326 if (!BN_mod_sqr(tmp_1, a, p, ctx)) goto err;
327 if (!BN_mod_mul(tmp_2, tmp_1, a, p, ctx)) goto err;
328 if (!BN_lshift(tmp_1, tmp_2, 2)) goto err;
331 if (!BN_mod_sqr(tmp_2, b, p, ctx)) goto err;
332 if (!BN_mul_word(tmp_2, 27)) goto err;
335 if (!BN_mod_add(a, tmp_1, tmp_2, p, ctx)) goto err;
336 if (BN_is_zero(a)) goto err;
344 BN_CTX_free(new_ctx);
349 int ec_GFp_simple_point_init(EC_POINT *point)
360 void ec_GFp_simple_point_finish(EC_POINT *point)
368 void ec_GFp_simple_point_clear_finish(EC_POINT *point)
370 BN_clear_free(&point->X);
371 BN_clear_free(&point->Y);
372 BN_clear_free(&point->Z);
377 int ec_GFp_simple_point_copy(EC_POINT *dest, const EC_POINT *src)
379 if (!BN_copy(&dest->X, &src->X)) return 0;
380 if (!BN_copy(&dest->Y, &src->Y)) return 0;
381 if (!BN_copy(&dest->Z, &src->Z)) return 0;
382 dest->Z_is_one = src->Z_is_one;
388 int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group, EC_POINT *point)
396 int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group, EC_POINT *point,
397 const BIGNUM *x, const BIGNUM *y, const BIGNUM *z, BN_CTX *ctx)
399 BN_CTX *new_ctx = NULL;
404 ctx = new_ctx = BN_CTX_new();
411 if (!BN_nnmod(&point->X, x, &group->field, ctx)) goto err;
412 if (group->meth->field_encode)
414 if (!group->meth->field_encode(group, &point->X, &point->X, ctx)) goto err;
420 if (!BN_nnmod(&point->Y, y, &group->field, ctx)) goto err;
421 if (group->meth->field_encode)
423 if (!group->meth->field_encode(group, &point->Y, &point->Y, ctx)) goto err;
431 if (!BN_nnmod(&point->Z, z, &group->field, ctx)) goto err;
432 Z_is_one = BN_is_one(&point->Z);
433 if (group->meth->field_encode)
435 if (Z_is_one && (group->meth->field_set_to_one != 0))
437 if (!group->meth->field_set_to_one(group, &point->Z, ctx)) goto err;
441 if (!group->meth->field_encode(group, &point->Z, &point->Z, ctx)) goto err;
444 point->Z_is_one = Z_is_one;
451 BN_CTX_free(new_ctx);
456 int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group, const EC_POINT *point,
457 BIGNUM *x, BIGNUM *y, BIGNUM *z, BN_CTX *ctx)
459 BN_CTX *new_ctx = NULL;
462 if (group->meth->field_decode != 0)
466 ctx = new_ctx = BN_CTX_new();
473 if (!group->meth->field_decode(group, x, &point->X, ctx)) goto err;
477 if (!group->meth->field_decode(group, y, &point->Y, ctx)) goto err;
481 if (!group->meth->field_decode(group, z, &point->Z, ctx)) goto err;
488 if (!BN_copy(x, &point->X)) goto err;
492 if (!BN_copy(y, &point->Y)) goto err;
496 if (!BN_copy(z, &point->Z)) goto err;
504 BN_CTX_free(new_ctx);
509 int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point,
510 const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx)
512 if (x == NULL || y == NULL)
514 /* unlike for projective coordinates, we do not tolerate this */
515 ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES, ERR_R_PASSED_NULL_PARAMETER);
519 return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y, BN_value_one(), ctx);
523 int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_POINT *point,
524 BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
526 BN_CTX *new_ctx = NULL;
527 BIGNUM *Z, *Z_1, *Z_2, *Z_3;
531 if (EC_POINT_is_at_infinity(group, point))
533 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY);
539 ctx = new_ctx = BN_CTX_new();
546 Z_1 = BN_CTX_get(ctx);
547 Z_2 = BN_CTX_get(ctx);
548 Z_3 = BN_CTX_get(ctx);
549 if (Z_3 == NULL) goto err;
551 /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
553 if (group->meth->field_decode)
555 if (!group->meth->field_decode(group, Z, &point->Z, ctx)) goto err;
565 if (group->meth->field_decode)
569 if (!group->meth->field_decode(group, x, &point->X, ctx)) goto err;
573 if (!group->meth->field_decode(group, y, &point->Y, ctx)) goto err;
580 if (!BN_copy(x, &point->X)) goto err;
584 if (!BN_copy(y, &point->Y)) goto err;
590 if (!BN_mod_inverse(Z_1, Z_, &group->field, ctx))
592 ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, ERR_R_BN_LIB);
596 if (group->meth->field_encode == 0)
598 /* field_sqr works on standard representation */
599 if (!group->meth->field_sqr(group, Z_2, Z_1, ctx)) goto err;
603 if (!BN_mod_sqr(Z_2, Z_1, &group->field, ctx)) goto err;
608 /* in the Montgomery case, field_mul will cancel out Montgomery factor in X: */
609 if (!group->meth->field_mul(group, x, &point->X, Z_2, ctx)) goto err;
614 if (group->meth->field_encode == 0)
616 /* field_mul works on standard representation */
617 if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx)) goto err;
621 if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx)) goto err;
624 /* in the Montgomery case, field_mul will cancel out Montgomery factor in Y: */
625 if (!group->meth->field_mul(group, y, &point->Y, Z_3, ctx)) goto err;
634 BN_CTX_free(new_ctx);
639 int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
640 const BIGNUM *x_, int y_bit, BN_CTX *ctx)
642 BN_CTX *new_ctx = NULL;
643 BIGNUM *tmp1, *tmp2, *x, *y;
646 /* clear error queue*/
651 ctx = new_ctx = BN_CTX_new();
656 y_bit = (y_bit != 0);
659 tmp1 = BN_CTX_get(ctx);
660 tmp2 = BN_CTX_get(ctx);
663 if (y == NULL) goto err;
665 /* Recover y. We have a Weierstrass equation
666 * y^2 = x^3 + a*x + b,
667 * so y is one of the square roots of x^3 + a*x + b.
671 if (!BN_nnmod(x, x_, &group->field,ctx)) goto err;
672 if (group->meth->field_decode == 0)
674 /* field_{sqr,mul} work on standard representation */
675 if (!group->meth->field_sqr(group, tmp2, x_, ctx)) goto err;
676 if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) goto err;
680 if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) goto err;
681 if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) goto err;
684 /* tmp1 := tmp1 + a*x */
685 if (group->a_is_minus3)
687 if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err;
688 if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err;
689 if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
693 if (group->meth->field_decode)
695 if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err;
696 if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err;
700 /* field_mul works on standard representation */
701 if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) goto err;
704 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
707 /* tmp1 := tmp1 + b */
708 if (group->meth->field_decode)
710 if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err;
711 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err;
715 if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err;
718 if (!BN_mod_sqrt(y, tmp1, &group->field, ctx))
720 unsigned long err = ERR_peek_last_error();
722 if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE)
725 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
728 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
732 if (y_bit != BN_is_odd(y))
738 kron = BN_kronecker(x, &group->field, ctx);
739 if (kron == -2) goto err;
742 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSION_BIT);
744 /* BN_mod_sqrt() should have cought this error (not a square) */
745 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
748 if (!BN_usub(y, &group->field, y)) goto err;
750 if (y_bit != BN_is_odd(y))
752 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_INTERNAL_ERROR);
756 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
763 BN_CTX_free(new_ctx);
768 size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form,
769 unsigned char *buf, size_t len, BN_CTX *ctx)
772 BN_CTX *new_ctx = NULL;
775 size_t field_len, i, skip;
777 if ((form != POINT_CONVERSION_COMPRESSED)
778 && (form != POINT_CONVERSION_UNCOMPRESSED)
779 && (form != POINT_CONVERSION_HYBRID))
781 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
785 if (EC_POINT_is_at_infinity(group, point))
787 /* encodes to a single 0 octet */
792 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
801 /* ret := required output buffer length */
802 field_len = BN_num_bytes(&group->field);
803 ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
805 /* if 'buf' is NULL, just return required length */
810 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
816 ctx = new_ctx = BN_CTX_new();
825 if (y == NULL) goto err;
827 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
829 if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
836 skip = field_len - BN_num_bytes(x);
837 if (skip > field_len)
839 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
847 skip = BN_bn2bin(x, buf + i);
849 if (i != 1 + field_len)
851 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
855 if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID)
857 skip = field_len - BN_num_bytes(y);
858 if (skip > field_len)
860 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
868 skip = BN_bn2bin(y, buf + i);
874 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
882 BN_CTX_free(new_ctx);
889 BN_CTX_free(new_ctx);
894 int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
895 const unsigned char *buf, size_t len, BN_CTX *ctx)
897 point_conversion_form_t form;
899 BN_CTX *new_ctx = NULL;
901 size_t field_len, enc_len;
906 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
912 if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
913 && (form != POINT_CONVERSION_UNCOMPRESSED)
914 && (form != POINT_CONVERSION_HYBRID))
916 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
919 if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit)
921 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
929 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
933 return EC_POINT_set_to_infinity(group, point);
936 field_len = BN_num_bytes(&group->field);
937 enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len;
941 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
947 ctx = new_ctx = BN_CTX_new();
955 if (y == NULL) goto err;
957 if (!BN_bin2bn(buf + 1, field_len, x)) goto err;
958 if (BN_ucmp(x, &group->field) >= 0)
960 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
964 if (form == POINT_CONVERSION_COMPRESSED)
966 if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err;
970 if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err;
971 if (BN_ucmp(y, &group->field) >= 0)
973 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
976 if (form == POINT_CONVERSION_HYBRID)
978 if (y_bit != BN_is_odd(y))
980 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
985 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
988 if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */
990 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
999 BN_CTX_free(new_ctx);
1004 int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx)
1006 int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
1007 int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
1009 BN_CTX *new_ctx = NULL;
1010 BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6;
1014 return EC_POINT_dbl(group, r, a, ctx);
1015 if (EC_POINT_is_at_infinity(group, a))
1016 return EC_POINT_copy(r, b);
1017 if (EC_POINT_is_at_infinity(group, b))
1018 return EC_POINT_copy(r, a);
1020 field_mul = group->meth->field_mul;
1021 field_sqr = group->meth->field_sqr;
1026 ctx = new_ctx = BN_CTX_new();
1032 n0 = BN_CTX_get(ctx);
1033 n1 = BN_CTX_get(ctx);
1034 n2 = BN_CTX_get(ctx);
1035 n3 = BN_CTX_get(ctx);
1036 n4 = BN_CTX_get(ctx);
1037 n5 = BN_CTX_get(ctx);
1038 n6 = BN_CTX_get(ctx);
1039 if (n6 == NULL) goto end;
1041 /* Note that in this function we must not read components of 'a' or 'b'
1042 * once we have written the corresponding components of 'r'.
1043 * ('r' might be one of 'a' or 'b'.)
1049 if (!BN_copy(n1, &a->X)) goto end;
1050 if (!BN_copy(n2, &a->Y)) goto end;
1056 if (!field_sqr(group, n0, &b->Z, ctx)) goto end;
1057 if (!field_mul(group, n1, &a->X, n0, ctx)) goto end;
1058 /* n1 = X_a * Z_b^2 */
1060 if (!field_mul(group, n0, n0, &b->Z, ctx)) goto end;
1061 if (!field_mul(group, n2, &a->Y, n0, ctx)) goto end;
1062 /* n2 = Y_a * Z_b^3 */
1068 if (!BN_copy(n3, &b->X)) goto end;
1069 if (!BN_copy(n4, &b->Y)) goto end;
1075 if (!field_sqr(group, n0, &a->Z, ctx)) goto end;
1076 if (!field_mul(group, n3, &b->X, n0, ctx)) goto end;
1077 /* n3 = X_b * Z_a^2 */
1079 if (!field_mul(group, n0, n0, &a->Z, ctx)) goto end;
1080 if (!field_mul(group, n4, &b->Y, n0, ctx)) goto end;
1081 /* n4 = Y_b * Z_a^3 */
1085 if (!BN_mod_sub_quick(n5, n1, n3, p)) goto end;
1086 if (!BN_mod_sub_quick(n6, n2, n4, p)) goto end;
1094 /* a is the same point as b */
1096 ret = EC_POINT_dbl(group, r, a, ctx);
1102 /* a is the inverse of b */
1111 if (!BN_mod_add_quick(n1, n1, n3, p)) goto end;
1112 if (!BN_mod_add_quick(n2, n2, n4, p)) goto end;
1113 /* 'n7' = n1 + n3 */
1114 /* 'n8' = n2 + n4 */
1117 if (a->Z_is_one && b->Z_is_one)
1119 if (!BN_copy(&r->Z, n5)) goto end;
1124 { if (!BN_copy(n0, &b->Z)) goto end; }
1125 else if (b->Z_is_one)
1126 { if (!BN_copy(n0, &a->Z)) goto end; }
1128 { if (!field_mul(group, n0, &a->Z, &b->Z, ctx)) goto end; }
1129 if (!field_mul(group, &r->Z, n0, n5, ctx)) goto end;
1132 /* Z_r = Z_a * Z_b * n5 */
1135 if (!field_sqr(group, n0, n6, ctx)) goto end;
1136 if (!field_sqr(group, n4, n5, ctx)) goto end;
1137 if (!field_mul(group, n3, n1, n4, ctx)) goto end;
1138 if (!BN_mod_sub_quick(&r->X, n0, n3, p)) goto end;
1139 /* X_r = n6^2 - n5^2 * 'n7' */
1142 if (!BN_mod_lshift1_quick(n0, &r->X, p)) goto end;
1143 if (!BN_mod_sub_quick(n0, n3, n0, p)) goto end;
1144 /* n9 = n5^2 * 'n7' - 2 * X_r */
1147 if (!field_mul(group, n0, n0, n6, ctx)) goto end;
1148 if (!field_mul(group, n5, n4, n5, ctx)) goto end; /* now n5 is n5^3 */
1149 if (!field_mul(group, n1, n2, n5, ctx)) goto end;
1150 if (!BN_mod_sub_quick(n0, n0, n1, p)) goto end;
1152 if (!BN_add(n0, n0, p)) goto end;
1153 /* now 0 <= n0 < 2*p, and n0 is even */
1154 if (!BN_rshift1(&r->Y, n0)) goto end;
1155 /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */
1160 if (ctx) /* otherwise we already called BN_CTX_end */
1162 if (new_ctx != NULL)
1163 BN_CTX_free(new_ctx);
1168 int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx)
1170 int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
1171 int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
1173 BN_CTX *new_ctx = NULL;
1174 BIGNUM *n0, *n1, *n2, *n3;
1177 if (EC_POINT_is_at_infinity(group, a))
1184 field_mul = group->meth->field_mul;
1185 field_sqr = group->meth->field_sqr;
1190 ctx = new_ctx = BN_CTX_new();
1196 n0 = BN_CTX_get(ctx);
1197 n1 = BN_CTX_get(ctx);
1198 n2 = BN_CTX_get(ctx);
1199 n3 = BN_CTX_get(ctx);
1200 if (n3 == NULL) goto err;
1202 /* Note that in this function we must not read components of 'a'
1203 * once we have written the corresponding components of 'r'.
1204 * ('r' might the same as 'a'.)
1210 if (!field_sqr(group, n0, &a->X, ctx)) goto err;
1211 if (!BN_mod_lshift1_quick(n1, n0, p)) goto err;
1212 if (!BN_mod_add_quick(n0, n0, n1, p)) goto err;
1213 if (!BN_mod_add_quick(n1, n0, &group->a, p)) goto err;
1214 /* n1 = 3 * X_a^2 + a_curve */
1216 else if (group->a_is_minus3)
1218 if (!field_sqr(group, n1, &a->Z, ctx)) goto err;
1219 if (!BN_mod_add_quick(n0, &a->X, n1, p)) goto err;
1220 if (!BN_mod_sub_quick(n2, &a->X, n1, p)) goto err;
1221 if (!field_mul(group, n1, n0, n2, ctx)) goto err;
1222 if (!BN_mod_lshift1_quick(n0, n1, p)) goto err;
1223 if (!BN_mod_add_quick(n1, n0, n1, p)) goto err;
1224 /* n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2)
1225 * = 3 * X_a^2 - 3 * Z_a^4 */
1229 if (!field_sqr(group, n0, &a->X, ctx)) goto err;
1230 if (!BN_mod_lshift1_quick(n1, n0, p)) goto err;
1231 if (!BN_mod_add_quick(n0, n0, n1, p)) goto err;
1232 if (!field_sqr(group, n1, &a->Z, ctx)) goto err;
1233 if (!field_sqr(group, n1, n1, ctx)) goto err;
1234 if (!field_mul(group, n1, n1, &group->a, ctx)) goto err;
1235 if (!BN_mod_add_quick(n1, n1, n0, p)) goto err;
1236 /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */
1242 if (!BN_copy(n0, &a->Y)) goto err;
1246 if (!field_mul(group, n0, &a->Y, &a->Z, ctx)) goto err;
1248 if (!BN_mod_lshift1_quick(&r->Z, n0, p)) goto err;
1250 /* Z_r = 2 * Y_a * Z_a */
1253 if (!field_sqr(group, n3, &a->Y, ctx)) goto err;
1254 if (!field_mul(group, n2, &a->X, n3, ctx)) goto err;
1255 if (!BN_mod_lshift_quick(n2, n2, 2, p)) goto err;
1256 /* n2 = 4 * X_a * Y_a^2 */
1259 if (!BN_mod_lshift1_quick(n0, n2, p)) goto err;
1260 if (!field_sqr(group, &r->X, n1, ctx)) goto err;
1261 if (!BN_mod_sub_quick(&r->X, &r->X, n0, p)) goto err;
1262 /* X_r = n1^2 - 2 * n2 */
1265 if (!field_sqr(group, n0, n3, ctx)) goto err;
1266 if (!BN_mod_lshift_quick(n3, n0, 3, p)) goto err;
1267 /* n3 = 8 * Y_a^4 */
1270 if (!BN_mod_sub_quick(n0, n2, &r->X, p)) goto err;
1271 if (!field_mul(group, n0, n1, n0, ctx)) goto err;
1272 if (!BN_mod_sub_quick(&r->Y, n0, n3, p)) goto err;
1273 /* Y_r = n1 * (n2 - X_r) - n3 */
1279 if (new_ctx != NULL)
1280 BN_CTX_free(new_ctx);
1285 int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
1287 if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(&point->Y))
1288 /* point is its own inverse */
1291 return BN_usub(&point->Y, &group->field, &point->Y);
1295 int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
1297 return BN_is_zero(&point->Z);
1301 int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx)
1303 int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
1304 int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
1306 BN_CTX *new_ctx = NULL;
1307 BIGNUM *rh, *tmp, *Z4, *Z6;
1310 if (EC_POINT_is_at_infinity(group, point))
1313 field_mul = group->meth->field_mul;
1314 field_sqr = group->meth->field_sqr;
1319 ctx = new_ctx = BN_CTX_new();
1325 rh = BN_CTX_get(ctx);
1326 tmp = BN_CTX_get(ctx);
1327 Z4 = BN_CTX_get(ctx);
1328 Z6 = BN_CTX_get(ctx);
1329 if (Z6 == NULL) goto err;
1332 * We have a curve defined by a Weierstrass equation
1333 * y^2 = x^3 + a*x + b.
1334 * The point to consider is given in Jacobian projective coordinates
1335 * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3).
1336 * Substituting this and multiplying by Z^6 transforms the above equation into
1337 * Y^2 = X^3 + a*X*Z^4 + b*Z^6.
1338 * To test this, we add up the right-hand side in 'rh'.
1342 if (!field_sqr(group, rh, &point->X, ctx)) goto err;
1344 if (!point->Z_is_one)
1346 if (!field_sqr(group, tmp, &point->Z, ctx)) goto err;
1347 if (!field_sqr(group, Z4, tmp, ctx)) goto err;
1348 if (!field_mul(group, Z6, Z4, tmp, ctx)) goto err;
1350 /* rh := (rh + a*Z^4)*X */
1351 if (group->a_is_minus3)
1353 if (!BN_mod_lshift1_quick(tmp, Z4, p)) goto err;
1354 if (!BN_mod_add_quick(tmp, tmp, Z4, p)) goto err;
1355 if (!BN_mod_sub_quick(rh, rh, tmp, p)) goto err;
1356 if (!field_mul(group, rh, rh, &point->X, ctx)) goto err;
1360 if (!field_mul(group, tmp, Z4, &group->a, ctx)) goto err;
1361 if (!BN_mod_add_quick(rh, rh, tmp, p)) goto err;
1362 if (!field_mul(group, rh, rh, &point->X, ctx)) goto err;
1365 /* rh := rh + b*Z^6 */
1366 if (!field_mul(group, tmp, &group->b, Z6, ctx)) goto err;
1367 if (!BN_mod_add_quick(rh, rh, tmp, p)) goto err;
1371 /* point->Z_is_one */
1373 /* rh := (rh + a)*X */
1374 if (!BN_mod_add_quick(rh, rh, &group->a, p)) goto err;
1375 if (!field_mul(group, rh, rh, &point->X, ctx)) goto err;
1377 if (!BN_mod_add_quick(rh, rh, &group->b, p)) goto err;
1381 if (!field_sqr(group, tmp, &point->Y, ctx)) goto err;
1383 ret = (0 == BN_ucmp(tmp, rh));
1387 if (new_ctx != NULL)
1388 BN_CTX_free(new_ctx);
1393 int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx)
1397 * 0 equal (in affine coordinates)
1401 int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
1402 int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *);
1403 BN_CTX *new_ctx = NULL;
1404 BIGNUM *tmp1, *tmp2, *Za23, *Zb23;
1405 const BIGNUM *tmp1_, *tmp2_;
1408 if (EC_POINT_is_at_infinity(group, a))
1410 return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
1413 if (EC_POINT_is_at_infinity(group, b))
1416 if (a->Z_is_one && b->Z_is_one)
1418 return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1;
1421 field_mul = group->meth->field_mul;
1422 field_sqr = group->meth->field_sqr;
1426 ctx = new_ctx = BN_CTX_new();
1432 tmp1 = BN_CTX_get(ctx);
1433 tmp2 = BN_CTX_get(ctx);
1434 Za23 = BN_CTX_get(ctx);
1435 Zb23 = BN_CTX_get(ctx);
1436 if (Zb23 == NULL) goto end;
1439 * We have to decide whether
1440 * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3),
1441 * or equivalently, whether
1442 * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3).
1447 if (!field_sqr(group, Zb23, &b->Z, ctx)) goto end;
1448 if (!field_mul(group, tmp1, &a->X, Zb23, ctx)) goto end;
1455 if (!field_sqr(group, Za23, &a->Z, ctx)) goto end;
1456 if (!field_mul(group, tmp2, &b->X, Za23, ctx)) goto end;
1462 /* compare X_a*Z_b^2 with X_b*Z_a^2 */
1463 if (BN_cmp(tmp1_, tmp2_) != 0)
1465 ret = 1; /* points differ */
1472 if (!field_mul(group, Zb23, Zb23, &b->Z, ctx)) goto end;
1473 if (!field_mul(group, tmp1, &a->Y, Zb23, ctx)) goto end;
1480 if (!field_mul(group, Za23, Za23, &a->Z, ctx)) goto end;
1481 if (!field_mul(group, tmp2, &b->Y, Za23, ctx)) goto end;
1487 /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */
1488 if (BN_cmp(tmp1_, tmp2_) != 0)
1490 ret = 1; /* points differ */
1494 /* points are equal */
1499 if (new_ctx != NULL)
1500 BN_CTX_free(new_ctx);
1505 int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
1507 BN_CTX *new_ctx = NULL;
1511 if (point->Z_is_one || EC_POINT_is_at_infinity(group, point))
1516 ctx = new_ctx = BN_CTX_new();
1522 x = BN_CTX_get(ctx);
1523 y = BN_CTX_get(ctx);
1524 if (y == NULL) goto err;
1526 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
1527 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err;
1528 if (!point->Z_is_one)
1530 ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR);
1538 if (new_ctx != NULL)
1539 BN_CTX_free(new_ctx);
1544 int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT *points[], BN_CTX *ctx)
1546 BN_CTX *new_ctx = NULL;
1547 BIGNUM *tmp, *tmp_Z;
1548 BIGNUM **prod_Z = NULL;
1557 ctx = new_ctx = BN_CTX_new();
1563 tmp = BN_CTX_get(ctx);
1564 tmp_Z = BN_CTX_get(ctx);
1565 if (tmp == NULL || tmp_Z == NULL) goto err;
1567 prod_Z = OPENSSL_malloc(num * sizeof prod_Z[0]);
1568 if (prod_Z == NULL) goto err;
1569 for (i = 0; i < num; i++)
1571 prod_Z[i] = BN_new();
1572 if (prod_Z[i] == NULL) goto err;
1575 /* Set each prod_Z[i] to the product of points[0]->Z .. points[i]->Z,
1576 * skipping any zero-valued inputs (pretend that they're 1). */
1578 if (!BN_is_zero(&points[0]->Z))
1580 if (!BN_copy(prod_Z[0], &points[0]->Z)) goto err;
1584 if (group->meth->field_set_to_one != 0)
1586 if (!group->meth->field_set_to_one(group, prod_Z[0], ctx)) goto err;
1590 if (!BN_one(prod_Z[0])) goto err;
1594 for (i = 1; i < num; i++)
1596 if (!BN_is_zero(&points[i]->Z))
1598 if (!group->meth->field_mul(group, prod_Z[i], prod_Z[i - 1], &points[i]->Z, ctx)) goto err;
1602 if (!BN_copy(prod_Z[i], prod_Z[i - 1])) goto err;
1606 /* Now use a single explicit inversion to replace every
1607 * non-zero points[i]->Z by its inverse. */
1609 if (!BN_mod_inverse(tmp, prod_Z[num - 1], &group->field, ctx))
1611 ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
1614 if (group->meth->field_encode != 0)
1616 /* In the Montgomery case, we just turned R*H (representing H)
1617 * into 1/(R*H), but we need R*(1/H) (representing 1/H);
1618 * i.e. we need to multiply by the Montgomery factor twice. */
1619 if (!group->meth->field_encode(group, tmp, tmp, ctx)) goto err;
1620 if (!group->meth->field_encode(group, tmp, tmp, ctx)) goto err;
1623 for (i = num - 1; i > 0; --i)
1625 /* Loop invariant: tmp is the product of the inverses of
1626 * points[0]->Z .. points[i]->Z (zero-valued inputs skipped). */
1627 if (!BN_is_zero(&points[i]->Z))
1629 /* Set tmp_Z to the inverse of points[i]->Z (as product
1630 * of Z inverses 0 .. i, Z values 0 .. i - 1). */
1631 if (!group->meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx)) goto err;
1632 /* Update tmp to satisfy the loop invariant for i - 1. */
1633 if (!group->meth->field_mul(group, tmp, tmp, &points[i]->Z, ctx)) goto err;
1634 /* Replace points[i]->Z by its inverse. */
1635 if (!BN_copy(&points[i]->Z, tmp_Z)) goto err;
1639 if (!BN_is_zero(&points[0]->Z))
1641 /* Replace points[0]->Z by its inverse. */
1642 if (!BN_copy(&points[0]->Z, tmp)) goto err;
1645 /* Finally, fix up the X and Y coordinates for all points. */
1647 for (i = 0; i < num; i++)
1649 EC_POINT *p = points[i];
1651 if (!BN_is_zero(&p->Z))
1653 /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */
1655 if (!group->meth->field_sqr(group, tmp, &p->Z, ctx)) goto err;
1656 if (!group->meth->field_mul(group, &p->X, &p->X, tmp, ctx)) goto err;
1658 if (!group->meth->field_mul(group, tmp, tmp, &p->Z, ctx)) goto err;
1659 if (!group->meth->field_mul(group, &p->Y, &p->Y, tmp, ctx)) goto err;
1661 if (group->meth->field_set_to_one != 0)
1663 if (!group->meth->field_set_to_one(group, &p->Z, ctx)) goto err;
1667 if (!BN_one(&p->Z)) goto err;
1677 if (new_ctx != NULL)
1678 BN_CTX_free(new_ctx);
1681 for (i = 0; i < num; i++)
1683 if (prod_Z[i] == NULL) break;
1684 BN_clear_free(prod_Z[i]);
1686 OPENSSL_free(prod_Z);
1692 int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
1694 return BN_mod_mul(r, a, b, &group->field, ctx);
1698 int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
1700 return BN_mod_sqr(r, a, &group->field, ctx);