diff options
Diffstat (limited to 'openssl/crypto/ec/ecp_smpl.c')
| -rw-r--r-- | openssl/crypto/ec/ecp_smpl.c | 1716 |
1 files changed, 1716 insertions, 0 deletions
diff --git a/openssl/crypto/ec/ecp_smpl.c b/openssl/crypto/ec/ecp_smpl.c new file mode 100644 index 000000000..4d26f8bdf --- /dev/null +++ b/openssl/crypto/ec/ecp_smpl.c @@ -0,0 +1,1716 @@ +/* crypto/ec/ecp_smpl.c */ +/* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de> + * for the OpenSSL project. + * Includes code written by Bodo Moeller for the OpenSSL project. +*/ +/* ==================================================================== + * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * ==================================================================== + * + * This product includes cryptographic software written by Eric Young + * (eay@cryptsoft.com). This product includes software written by Tim + * Hudson (tjh@cryptsoft.com). + * + */ +/* ==================================================================== + * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. + * Portions of this software developed by SUN MICROSYSTEMS, INC., + * and contributed to the OpenSSL project. + */ + +#include <openssl/err.h> +#include <openssl/symhacks.h> + +#include "ec_lcl.h" + +const EC_METHOD *EC_GFp_simple_method(void) + { + static const EC_METHOD ret = { + NID_X9_62_prime_field, + ec_GFp_simple_group_init, + ec_GFp_simple_group_finish, + ec_GFp_simple_group_clear_finish, + ec_GFp_simple_group_copy, + ec_GFp_simple_group_set_curve, + ec_GFp_simple_group_get_curve, + ec_GFp_simple_group_get_degree, + ec_GFp_simple_group_check_discriminant, + ec_GFp_simple_point_init, + ec_GFp_simple_point_finish, + ec_GFp_simple_point_clear_finish, + ec_GFp_simple_point_copy, + ec_GFp_simple_point_set_to_infinity, + ec_GFp_simple_set_Jprojective_coordinates_GFp, + ec_GFp_simple_get_Jprojective_coordinates_GFp, + ec_GFp_simple_point_set_affine_coordinates, + ec_GFp_simple_point_get_affine_coordinates, + ec_GFp_simple_set_compressed_coordinates, + ec_GFp_simple_point2oct, + ec_GFp_simple_oct2point, + ec_GFp_simple_add, + ec_GFp_simple_dbl, + ec_GFp_simple_invert, + ec_GFp_simple_is_at_infinity, + ec_GFp_simple_is_on_curve, + ec_GFp_simple_cmp, + ec_GFp_simple_make_affine, + ec_GFp_simple_points_make_affine, + 0 /* mul */, + 0 /* precompute_mult */, + 0 /* have_precompute_mult */, + ec_GFp_simple_field_mul, + ec_GFp_simple_field_sqr, + 0 /* field_div */, + 0 /* field_encode */, + 0 /* field_decode */, + 0 /* field_set_to_one */ }; + + return &ret; + } + + +/* Most method functions in this file are designed to work with + * non-trivial representations of field elements if necessary + * (see ecp_mont.c): while standard modular addition and subtraction + * are used, the field_mul and field_sqr methods will be used for + * multiplication, and field_encode and field_decode (if defined) + * will be used for converting between representations. + + * Functions ec_GFp_simple_points_make_affine() and + * ec_GFp_simple_point_get_affine_coordinates() specifically assume + * that if a non-trivial representation is used, it is a Montgomery + * representation (i.e. 'encoding' means multiplying by some factor R). + */ + + +int ec_GFp_simple_group_init(EC_GROUP *group) + { + BN_init(&group->field); + BN_init(&group->a); + BN_init(&group->b); + group->a_is_minus3 = 0; + return 1; + } + + +void ec_GFp_simple_group_finish(EC_GROUP *group) + { + BN_free(&group->field); + BN_free(&group->a); + BN_free(&group->b); + } + + +void ec_GFp_simple_group_clear_finish(EC_GROUP *group) + { + BN_clear_free(&group->field); + BN_clear_free(&group->a); + BN_clear_free(&group->b); + } + + +int ec_GFp_simple_group_copy(EC_GROUP *dest, const EC_GROUP *src) + { + if (!BN_copy(&dest->field, &src->field)) return 0; + if (!BN_copy(&dest->a, &src->a)) return 0; + if (!BN_copy(&dest->b, &src->b)) return 0; + + dest->a_is_minus3 = src->a_is_minus3; + + return 1; + } + + +int ec_GFp_simple_group_set_curve(EC_GROUP *group, + const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) + { + int ret = 0; + BN_CTX *new_ctx = NULL; + BIGNUM *tmp_a; + + /* p must be a prime > 3 */ + if (BN_num_bits(p) <= 2 || !BN_is_odd(p)) + { + ECerr(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE, EC_R_INVALID_FIELD); + return 0; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + tmp_a = BN_CTX_get(ctx); + if (tmp_a == NULL) goto err; + + /* group->field */ + if (!BN_copy(&group->field, p)) goto err; + BN_set_negative(&group->field, 0); + + /* group->a */ + if (!BN_nnmod(tmp_a, a, p, ctx)) goto err; + if (group->meth->field_encode) + { if (!group->meth->field_encode(group, &group->a, tmp_a, ctx)) goto err; } + else + if (!BN_copy(&group->a, tmp_a)) goto err; + + /* group->b */ + if (!BN_nnmod(&group->b, b, p, ctx)) goto err; + if (group->meth->field_encode) + if (!group->meth->field_encode(group, &group->b, &group->b, ctx)) goto err; + + /* group->a_is_minus3 */ + if (!BN_add_word(tmp_a, 3)) goto err; + group->a_is_minus3 = (0 == BN_cmp(tmp_a, &group->field)); + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx) + { + int ret = 0; + BN_CTX *new_ctx = NULL; + + if (p != NULL) + { + if (!BN_copy(p, &group->field)) return 0; + } + + if (a != NULL || b != NULL) + { + if (group->meth->field_decode) + { + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + if (a != NULL) + { + if (!group->meth->field_decode(group, a, &group->a, ctx)) goto err; + } + if (b != NULL) + { + if (!group->meth->field_decode(group, b, &group->b, ctx)) goto err; + } + } + else + { + if (a != NULL) + { + if (!BN_copy(a, &group->a)) goto err; + } + if (b != NULL) + { + if (!BN_copy(b, &group->b)) goto err; + } + } + } + + ret = 1; + + err: + if (new_ctx) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_group_get_degree(const EC_GROUP *group) + { + return BN_num_bits(&group->field); + } + + +int ec_GFp_simple_group_check_discriminant(const EC_GROUP *group, BN_CTX *ctx) + { + int ret = 0; + BIGNUM *a,*b,*order,*tmp_1,*tmp_2; + const BIGNUM *p = &group->field; + BN_CTX *new_ctx = NULL; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + { + ECerr(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT, ERR_R_MALLOC_FAILURE); + goto err; + } + } + BN_CTX_start(ctx); + a = BN_CTX_get(ctx); + b = BN_CTX_get(ctx); + tmp_1 = BN_CTX_get(ctx); + tmp_2 = BN_CTX_get(ctx); + order = BN_CTX_get(ctx); + if (order == NULL) goto err; + + if (group->meth->field_decode) + { + if (!group->meth->field_decode(group, a, &group->a, ctx)) goto err; + if (!group->meth->field_decode(group, b, &group->b, ctx)) goto err; + } + else + { + if (!BN_copy(a, &group->a)) goto err; + if (!BN_copy(b, &group->b)) goto err; + } + + /* check the discriminant: + * y^2 = x^3 + a*x + b is an elliptic curve <=> 4*a^3 + 27*b^2 != 0 (mod p) + * 0 =< a, b < p */ + if (BN_is_zero(a)) + { + if (BN_is_zero(b)) goto err; + } + else if (!BN_is_zero(b)) + { + if (!BN_mod_sqr(tmp_1, a, p, ctx)) goto err; + if (!BN_mod_mul(tmp_2, tmp_1, a, p, ctx)) goto err; + if (!BN_lshift(tmp_1, tmp_2, 2)) goto err; + /* tmp_1 = 4*a^3 */ + + if (!BN_mod_sqr(tmp_2, b, p, ctx)) goto err; + if (!BN_mul_word(tmp_2, 27)) goto err; + /* tmp_2 = 27*b^2 */ + + if (!BN_mod_add(a, tmp_1, tmp_2, p, ctx)) goto err; + if (BN_is_zero(a)) goto err; + } + ret = 1; + +err: + if (ctx != NULL) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_point_init(EC_POINT *point) + { + BN_init(&point->X); + BN_init(&point->Y); + BN_init(&point->Z); + point->Z_is_one = 0; + + return 1; + } + + +void ec_GFp_simple_point_finish(EC_POINT *point) + { + BN_free(&point->X); + BN_free(&point->Y); + BN_free(&point->Z); + } + + +void ec_GFp_simple_point_clear_finish(EC_POINT *point) + { + BN_clear_free(&point->X); + BN_clear_free(&point->Y); + BN_clear_free(&point->Z); + point->Z_is_one = 0; + } + + +int ec_GFp_simple_point_copy(EC_POINT *dest, const EC_POINT *src) + { + if (!BN_copy(&dest->X, &src->X)) return 0; + if (!BN_copy(&dest->Y, &src->Y)) return 0; + if (!BN_copy(&dest->Z, &src->Z)) return 0; + dest->Z_is_one = src->Z_is_one; + + return 1; + } + + +int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *group, EC_POINT *point) + { + point->Z_is_one = 0; + BN_zero(&point->Z); + return 1; + } + + +int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x, const BIGNUM *y, const BIGNUM *z, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + int ret = 0; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + if (x != NULL) + { + if (!BN_nnmod(&point->X, x, &group->field, ctx)) goto err; + if (group->meth->field_encode) + { + if (!group->meth->field_encode(group, &point->X, &point->X, ctx)) goto err; + } + } + + if (y != NULL) + { + if (!BN_nnmod(&point->Y, y, &group->field, ctx)) goto err; + if (group->meth->field_encode) + { + if (!group->meth->field_encode(group, &point->Y, &point->Y, ctx)) goto err; + } + } + + if (z != NULL) + { + int Z_is_one; + + if (!BN_nnmod(&point->Z, z, &group->field, ctx)) goto err; + Z_is_one = BN_is_one(&point->Z); + if (group->meth->field_encode) + { + if (Z_is_one && (group->meth->field_set_to_one != 0)) + { + if (!group->meth->field_set_to_one(group, &point->Z, ctx)) goto err; + } + else + { + if (!group->meth->field_encode(group, &point->Z, &point->Z, ctx)) goto err; + } + } + point->Z_is_one = Z_is_one; + } + + ret = 1; + + err: + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *group, const EC_POINT *point, + BIGNUM *x, BIGNUM *y, BIGNUM *z, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + int ret = 0; + + if (group->meth->field_decode != 0) + { + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + if (x != NULL) + { + if (!group->meth->field_decode(group, x, &point->X, ctx)) goto err; + } + if (y != NULL) + { + if (!group->meth->field_decode(group, y, &point->Y, ctx)) goto err; + } + if (z != NULL) + { + if (!group->meth->field_decode(group, z, &point->Z, ctx)) goto err; + } + } + else + { + if (x != NULL) + { + if (!BN_copy(x, &point->X)) goto err; + } + if (y != NULL) + { + if (!BN_copy(y, &point->Y)) goto err; + } + if (z != NULL) + { + if (!BN_copy(z, &point->Z)) goto err; + } + } + + ret = 1; + + err: + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx) + { + if (x == NULL || y == NULL) + { + /* unlike for projective coordinates, we do not tolerate this */ + ECerr(EC_F_EC_GFP_SIMPLE_POINT_SET_AFFINE_COORDINATES, ERR_R_PASSED_NULL_PARAMETER); + return 0; + } + + return EC_POINT_set_Jprojective_coordinates_GFp(group, point, x, y, BN_value_one(), ctx); + } + + +int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group, const EC_POINT *point, + BIGNUM *x, BIGNUM *y, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *Z, *Z_1, *Z_2, *Z_3; + const BIGNUM *Z_; + int ret = 0; + + if (EC_POINT_is_at_infinity(group, point)) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY); + return 0; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + Z = BN_CTX_get(ctx); + Z_1 = BN_CTX_get(ctx); + Z_2 = BN_CTX_get(ctx); + Z_3 = BN_CTX_get(ctx); + if (Z_3 == NULL) goto err; + + /* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */ + + if (group->meth->field_decode) + { + if (!group->meth->field_decode(group, Z, &point->Z, ctx)) goto err; + Z_ = Z; + } + else + { + Z_ = &point->Z; + } + + if (BN_is_one(Z_)) + { + if (group->meth->field_decode) + { + if (x != NULL) + { + if (!group->meth->field_decode(group, x, &point->X, ctx)) goto err; + } + if (y != NULL) + { + if (!group->meth->field_decode(group, y, &point->Y, ctx)) goto err; + } + } + else + { + if (x != NULL) + { + if (!BN_copy(x, &point->X)) goto err; + } + if (y != NULL) + { + if (!BN_copy(y, &point->Y)) goto err; + } + } + } + else + { + if (!BN_mod_inverse(Z_1, Z_, &group->field, ctx)) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES, ERR_R_BN_LIB); + goto err; + } + + if (group->meth->field_encode == 0) + { + /* field_sqr works on standard representation */ + if (!group->meth->field_sqr(group, Z_2, Z_1, ctx)) goto err; + } + else + { + if (!BN_mod_sqr(Z_2, Z_1, &group->field, ctx)) goto err; + } + + if (x != NULL) + { + /* in the Montgomery case, field_mul will cancel out Montgomery factor in X: */ + if (!group->meth->field_mul(group, x, &point->X, Z_2, ctx)) goto err; + } + + if (y != NULL) + { + if (group->meth->field_encode == 0) + { + /* field_mul works on standard representation */ + if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx)) goto err; + } + else + { + if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx)) goto err; + } + + /* in the Montgomery case, field_mul will cancel out Montgomery factor in Y: */ + if (!group->meth->field_mul(group, y, &point->Y, Z_3, ctx)) goto err; + } + } + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point, + const BIGNUM *x_, int y_bit, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *tmp1, *tmp2, *x, *y; + int ret = 0; + + /* clear error queue*/ + ERR_clear_error(); + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + y_bit = (y_bit != 0); + + BN_CTX_start(ctx); + tmp1 = BN_CTX_get(ctx); + tmp2 = BN_CTX_get(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) goto err; + + /* Recover y. We have a Weierstrass equation + * y^2 = x^3 + a*x + b, + * so y is one of the square roots of x^3 + a*x + b. + */ + + /* tmp1 := x^3 */ + if (!BN_nnmod(x, x_, &group->field,ctx)) goto err; + if (group->meth->field_decode == 0) + { + /* field_{sqr,mul} work on standard representation */ + if (!group->meth->field_sqr(group, tmp2, x_, ctx)) goto err; + if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx)) goto err; + } + else + { + if (!BN_mod_sqr(tmp2, x_, &group->field, ctx)) goto err; + if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx)) goto err; + } + + /* tmp1 := tmp1 + a*x */ + if (group->a_is_minus3) + { + if (!BN_mod_lshift1_quick(tmp2, x, &group->field)) goto err; + if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field)) goto err; + if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field)) goto err; + } + else + { + if (group->meth->field_decode) + { + if (!group->meth->field_decode(group, tmp2, &group->a, ctx)) goto err; + if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx)) goto err; + } + else + { + /* field_mul works on standard representation */ + if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx)) goto err; + } + + if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err; + } + + /* tmp1 := tmp1 + b */ + if (group->meth->field_decode) + { + if (!group->meth->field_decode(group, tmp2, &group->b, ctx)) goto err; + if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field)) goto err; + } + else + { + if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field)) goto err; + } + + if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) + { + unsigned long err = ERR_peek_last_error(); + + if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) + { + ERR_clear_error(); + ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT); + } + else + ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB); + goto err; + } + + if (y_bit != BN_is_odd(y)) + { + if (BN_is_zero(y)) + { + int kron; + + kron = BN_kronecker(x, &group->field, ctx); + if (kron == -2) goto err; + + if (kron == 1) + ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSION_BIT); + else + /* BN_mod_sqrt() should have cought this error (not a square) */ + ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT); + goto err; + } + if (!BN_usub(y, &group->field, y)) goto err; + } + if (y_bit != BN_is_odd(y)) + { + ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_INTERNAL_ERROR); + goto err; + } + + if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err; + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point, point_conversion_form_t form, + unsigned char *buf, size_t len, BN_CTX *ctx) + { + size_t ret; + BN_CTX *new_ctx = NULL; + int used_ctx = 0; + BIGNUM *x, *y; + size_t field_len, i, skip; + + if ((form != POINT_CONVERSION_COMPRESSED) + && (form != POINT_CONVERSION_UNCOMPRESSED) + && (form != POINT_CONVERSION_HYBRID)) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM); + goto err; + } + + if (EC_POINT_is_at_infinity(group, point)) + { + /* encodes to a single 0 octet */ + if (buf != NULL) + { + if (len < 1) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); + return 0; + } + buf[0] = 0; + } + return 1; + } + + + /* ret := required output buffer length */ + field_len = BN_num_bytes(&group->field); + ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; + + /* if 'buf' is NULL, just return required length */ + if (buf != NULL) + { + if (len < ret) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL); + goto err; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + used_ctx = 1; + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) goto err; + + if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err; + + if ((form == POINT_CONVERSION_COMPRESSED || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y)) + buf[0] = form + 1; + else + buf[0] = form; + + i = 1; + + skip = field_len - BN_num_bytes(x); + if (skip > field_len) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + while (skip > 0) + { + buf[i++] = 0; + skip--; + } + skip = BN_bn2bin(x, buf + i); + i += skip; + if (i != 1 + field_len) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + + if (form == POINT_CONVERSION_UNCOMPRESSED || form == POINT_CONVERSION_HYBRID) + { + skip = field_len - BN_num_bytes(y); + if (skip > field_len) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + while (skip > 0) + { + buf[i++] = 0; + skip--; + } + skip = BN_bn2bin(y, buf + i); + i += skip; + } + + if (i != ret) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR); + goto err; + } + } + + if (used_ctx) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + + err: + if (used_ctx) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return 0; + } + + +int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point, + const unsigned char *buf, size_t len, BN_CTX *ctx) + { + point_conversion_form_t form; + int y_bit; + BN_CTX *new_ctx = NULL; + BIGNUM *x, *y; + size_t field_len, enc_len; + int ret = 0; + + if (len == 0) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL); + return 0; + } + form = buf[0]; + y_bit = form & 1; + form = form & ~1U; + if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED) + && (form != POINT_CONVERSION_UNCOMPRESSED) + && (form != POINT_CONVERSION_HYBRID)) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + if (form == 0) + { + if (len != 1) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + return EC_POINT_set_to_infinity(group, point); + } + + field_len = BN_num_bytes(&group->field); + enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2*field_len; + + if (len != enc_len) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + return 0; + } + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) goto err; + + if (!BN_bin2bn(buf + 1, field_len, x)) goto err; + if (BN_ucmp(x, &group->field) >= 0) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + + if (form == POINT_CONVERSION_COMPRESSED) + { + if (!EC_POINT_set_compressed_coordinates_GFp(group, point, x, y_bit, ctx)) goto err; + } + else + { + if (!BN_bin2bn(buf + 1 + field_len, field_len, y)) goto err; + if (BN_ucmp(y, &group->field) >= 0) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + if (form == POINT_CONVERSION_HYBRID) + { + if (y_bit != BN_is_odd(y)) + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING); + goto err; + } + } + + if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err; + } + + if (!EC_POINT_is_on_curve(group, point, ctx)) /* test required by X9.62 */ + { + ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE); + goto err; + } + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx) + { + int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); + int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); + const BIGNUM *p; + BN_CTX *new_ctx = NULL; + BIGNUM *n0, *n1, *n2, *n3, *n4, *n5, *n6; + int ret = 0; + + if (a == b) + return EC_POINT_dbl(group, r, a, ctx); + if (EC_POINT_is_at_infinity(group, a)) + return EC_POINT_copy(r, b); + if (EC_POINT_is_at_infinity(group, b)) + return EC_POINT_copy(r, a); + + field_mul = group->meth->field_mul; + field_sqr = group->meth->field_sqr; + p = &group->field; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + n0 = BN_CTX_get(ctx); + n1 = BN_CTX_get(ctx); + n2 = BN_CTX_get(ctx); + n3 = BN_CTX_get(ctx); + n4 = BN_CTX_get(ctx); + n5 = BN_CTX_get(ctx); + n6 = BN_CTX_get(ctx); + if (n6 == NULL) goto end; + + /* Note that in this function we must not read components of 'a' or 'b' + * once we have written the corresponding components of 'r'. + * ('r' might be one of 'a' or 'b'.) + */ + + /* n1, n2 */ + if (b->Z_is_one) + { + if (!BN_copy(n1, &a->X)) goto end; + if (!BN_copy(n2, &a->Y)) goto end; + /* n1 = X_a */ + /* n2 = Y_a */ + } + else + { + if (!field_sqr(group, n0, &b->Z, ctx)) goto end; + if (!field_mul(group, n1, &a->X, n0, ctx)) goto end; + /* n1 = X_a * Z_b^2 */ + + if (!field_mul(group, n0, n0, &b->Z, ctx)) goto end; + if (!field_mul(group, n2, &a->Y, n0, ctx)) goto end; + /* n2 = Y_a * Z_b^3 */ + } + + /* n3, n4 */ + if (a->Z_is_one) + { + if (!BN_copy(n3, &b->X)) goto end; + if (!BN_copy(n4, &b->Y)) goto end; + /* n3 = X_b */ + /* n4 = Y_b */ + } + else + { + if (!field_sqr(group, n0, &a->Z, ctx)) goto end; + if (!field_mul(group, n3, &b->X, n0, ctx)) goto end; + /* n3 = X_b * Z_a^2 */ + + if (!field_mul(group, n0, n0, &a->Z, ctx)) goto end; + if (!field_mul(group, n4, &b->Y, n0, ctx)) goto end; + /* n4 = Y_b * Z_a^3 */ + } + + /* n5, n6 */ + if (!BN_mod_sub_quick(n5, n1, n3, p)) goto end; + if (!BN_mod_sub_quick(n6, n2, n4, p)) goto end; + /* n5 = n1 - n3 */ + /* n6 = n2 - n4 */ + + if (BN_is_zero(n5)) + { + if (BN_is_zero(n6)) + { + /* a is the same point as b */ + BN_CTX_end(ctx); + ret = EC_POINT_dbl(group, r, a, ctx); + ctx = NULL; + goto end; + } + else + { + /* a is the inverse of b */ + BN_zero(&r->Z); + r->Z_is_one = 0; + ret = 1; + goto end; + } + } + + /* 'n7', 'n8' */ + if (!BN_mod_add_quick(n1, n1, n3, p)) goto end; + if (!BN_mod_add_quick(n2, n2, n4, p)) goto end; + /* 'n7' = n1 + n3 */ + /* 'n8' = n2 + n4 */ + + /* Z_r */ + if (a->Z_is_one && b->Z_is_one) + { + if (!BN_copy(&r->Z, n5)) goto end; + } + else + { + if (a->Z_is_one) + { if (!BN_copy(n0, &b->Z)) goto end; } + else if (b->Z_is_one) + { if (!BN_copy(n0, &a->Z)) goto end; } + else + { if (!field_mul(group, n0, &a->Z, &b->Z, ctx)) goto end; } + if (!field_mul(group, &r->Z, n0, n5, ctx)) goto end; + } + r->Z_is_one = 0; + /* Z_r = Z_a * Z_b * n5 */ + + /* X_r */ + if (!field_sqr(group, n0, n6, ctx)) goto end; + if (!field_sqr(group, n4, n5, ctx)) goto end; + if (!field_mul(group, n3, n1, n4, ctx)) goto end; + if (!BN_mod_sub_quick(&r->X, n0, n3, p)) goto end; + /* X_r = n6^2 - n5^2 * 'n7' */ + + /* 'n9' */ + if (!BN_mod_lshift1_quick(n0, &r->X, p)) goto end; + if (!BN_mod_sub_quick(n0, n3, n0, p)) goto end; + /* n9 = n5^2 * 'n7' - 2 * X_r */ + + /* Y_r */ + if (!field_mul(group, n0, n0, n6, ctx)) goto end; + if (!field_mul(group, n5, n4, n5, ctx)) goto end; /* now n5 is n5^3 */ + if (!field_mul(group, n1, n2, n5, ctx)) goto end; + if (!BN_mod_sub_quick(n0, n0, n1, p)) goto end; + if (BN_is_odd(n0)) + if (!BN_add(n0, n0, p)) goto end; + /* now 0 <= n0 < 2*p, and n0 is even */ + if (!BN_rshift1(&r->Y, n0)) goto end; + /* Y_r = (n6 * 'n9' - 'n8' * 'n5^3') / 2 */ + + ret = 1; + + end: + if (ctx) /* otherwise we already called BN_CTX_end */ + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx) + { + int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); + int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); + const BIGNUM *p; + BN_CTX *new_ctx = NULL; + BIGNUM *n0, *n1, *n2, *n3; + int ret = 0; + + if (EC_POINT_is_at_infinity(group, a)) + { + BN_zero(&r->Z); + r->Z_is_one = 0; + return 1; + } + + field_mul = group->meth->field_mul; + field_sqr = group->meth->field_sqr; + p = &group->field; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + n0 = BN_CTX_get(ctx); + n1 = BN_CTX_get(ctx); + n2 = BN_CTX_get(ctx); + n3 = BN_CTX_get(ctx); + if (n3 == NULL) goto err; + + /* Note that in this function we must not read components of 'a' + * once we have written the corresponding components of 'r'. + * ('r' might the same as 'a'.) + */ + + /* n1 */ + if (a->Z_is_one) + { + if (!field_sqr(group, n0, &a->X, ctx)) goto err; + if (!BN_mod_lshift1_quick(n1, n0, p)) goto err; + if (!BN_mod_add_quick(n0, n0, n1, p)) goto err; + if (!BN_mod_add_quick(n1, n0, &group->a, p)) goto err; + /* n1 = 3 * X_a^2 + a_curve */ + } + else if (group->a_is_minus3) + { + if (!field_sqr(group, n1, &a->Z, ctx)) goto err; + if (!BN_mod_add_quick(n0, &a->X, n1, p)) goto err; + if (!BN_mod_sub_quick(n2, &a->X, n1, p)) goto err; + if (!field_mul(group, n1, n0, n2, ctx)) goto err; + if (!BN_mod_lshift1_quick(n0, n1, p)) goto err; + if (!BN_mod_add_quick(n1, n0, n1, p)) goto err; + /* n1 = 3 * (X_a + Z_a^2) * (X_a - Z_a^2) + * = 3 * X_a^2 - 3 * Z_a^4 */ + } + else + { + if (!field_sqr(group, n0, &a->X, ctx)) goto err; + if (!BN_mod_lshift1_quick(n1, n0, p)) goto err; + if (!BN_mod_add_quick(n0, n0, n1, p)) goto err; + if (!field_sqr(group, n1, &a->Z, ctx)) goto err; + if (!field_sqr(group, n1, n1, ctx)) goto err; + if (!field_mul(group, n1, n1, &group->a, ctx)) goto err; + if (!BN_mod_add_quick(n1, n1, n0, p)) goto err; + /* n1 = 3 * X_a^2 + a_curve * Z_a^4 */ + } + + /* Z_r */ + if (a->Z_is_one) + { + if (!BN_copy(n0, &a->Y)) goto err; + } + else + { + if (!field_mul(group, n0, &a->Y, &a->Z, ctx)) goto err; + } + if (!BN_mod_lshift1_quick(&r->Z, n0, p)) goto err; + r->Z_is_one = 0; + /* Z_r = 2 * Y_a * Z_a */ + + /* n2 */ + if (!field_sqr(group, n3, &a->Y, ctx)) goto err; + if (!field_mul(group, n2, &a->X, n3, ctx)) goto err; + if (!BN_mod_lshift_quick(n2, n2, 2, p)) goto err; + /* n2 = 4 * X_a * Y_a^2 */ + + /* X_r */ + if (!BN_mod_lshift1_quick(n0, n2, p)) goto err; + if (!field_sqr(group, &r->X, n1, ctx)) goto err; + if (!BN_mod_sub_quick(&r->X, &r->X, n0, p)) goto err; + /* X_r = n1^2 - 2 * n2 */ + + /* n3 */ + if (!field_sqr(group, n0, n3, ctx)) goto err; + if (!BN_mod_lshift_quick(n3, n0, 3, p)) goto err; + /* n3 = 8 * Y_a^4 */ + + /* Y_r */ + if (!BN_mod_sub_quick(n0, n2, &r->X, p)) goto err; + if (!field_mul(group, n0, n1, n0, ctx)) goto err; + if (!BN_mod_sub_quick(&r->Y, n0, n3, p)) goto err; + /* Y_r = n1 * (n2 - X_r) - n3 */ + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_invert(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) + { + if (EC_POINT_is_at_infinity(group, point) || BN_is_zero(&point->Y)) + /* point is its own inverse */ + return 1; + + return BN_usub(&point->Y, &group->field, &point->Y); + } + + +int ec_GFp_simple_is_at_infinity(const EC_GROUP *group, const EC_POINT *point) + { + return BN_is_zero(&point->Z); + } + + +int ec_GFp_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx) + { + int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); + int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); + const BIGNUM *p; + BN_CTX *new_ctx = NULL; + BIGNUM *rh, *tmp, *Z4, *Z6; + int ret = -1; + + if (EC_POINT_is_at_infinity(group, point)) + return 1; + + field_mul = group->meth->field_mul; + field_sqr = group->meth->field_sqr; + p = &group->field; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return -1; + } + + BN_CTX_start(ctx); + rh = BN_CTX_get(ctx); + tmp = BN_CTX_get(ctx); + Z4 = BN_CTX_get(ctx); + Z6 = BN_CTX_get(ctx); + if (Z6 == NULL) goto err; + + /* We have a curve defined by a Weierstrass equation + * y^2 = x^3 + a*x + b. + * The point to consider is given in Jacobian projective coordinates + * where (X, Y, Z) represents (x, y) = (X/Z^2, Y/Z^3). + * Substituting this and multiplying by Z^6 transforms the above equation into + * Y^2 = X^3 + a*X*Z^4 + b*Z^6. + * To test this, we add up the right-hand side in 'rh'. + */ + + /* rh := X^2 */ + if (!field_sqr(group, rh, &point->X, ctx)) goto err; + + if (!point->Z_is_one) + { + if (!field_sqr(group, tmp, &point->Z, ctx)) goto err; + if (!field_sqr(group, Z4, tmp, ctx)) goto err; + if (!field_mul(group, Z6, Z4, tmp, ctx)) goto err; + + /* rh := (rh + a*Z^4)*X */ + if (group->a_is_minus3) + { + if (!BN_mod_lshift1_quick(tmp, Z4, p)) goto err; + if (!BN_mod_add_quick(tmp, tmp, Z4, p)) goto err; + if (!BN_mod_sub_quick(rh, rh, tmp, p)) goto err; + if (!field_mul(group, rh, rh, &point->X, ctx)) goto err; + } + else + { + if (!field_mul(group, tmp, Z4, &group->a, ctx)) goto err; + if (!BN_mod_add_quick(rh, rh, tmp, p)) goto err; + if (!field_mul(group, rh, rh, &point->X, ctx)) goto err; + } + + /* rh := rh + b*Z^6 */ + if (!field_mul(group, tmp, &group->b, Z6, ctx)) goto err; + if (!BN_mod_add_quick(rh, rh, tmp, p)) goto err; + } + else + { + /* point->Z_is_one */ + + /* rh := (rh + a)*X */ + if (!BN_mod_add_quick(rh, rh, &group->a, p)) goto err; + if (!field_mul(group, rh, rh, &point->X, ctx)) goto err; + /* rh := rh + b */ + if (!BN_mod_add_quick(rh, rh, &group->b, p)) goto err; + } + + /* 'lh' := Y^2 */ + if (!field_sqr(group, tmp, &point->Y, ctx)) goto err; + + ret = (0 == BN_ucmp(tmp, rh)); + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx) + { + /* return values: + * -1 error + * 0 equal (in affine coordinates) + * 1 not equal + */ + + int (*field_mul)(const EC_GROUP *, BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); + int (*field_sqr)(const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); + BN_CTX *new_ctx = NULL; + BIGNUM *tmp1, *tmp2, *Za23, *Zb23; + const BIGNUM *tmp1_, *tmp2_; + int ret = -1; + + if (EC_POINT_is_at_infinity(group, a)) + { + return EC_POINT_is_at_infinity(group, b) ? 0 : 1; + } + + if (a->Z_is_one && b->Z_is_one) + { + return ((BN_cmp(&a->X, &b->X) == 0) && BN_cmp(&a->Y, &b->Y) == 0) ? 0 : 1; + } + + field_mul = group->meth->field_mul; + field_sqr = group->meth->field_sqr; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return -1; + } + + BN_CTX_start(ctx); + tmp1 = BN_CTX_get(ctx); + tmp2 = BN_CTX_get(ctx); + Za23 = BN_CTX_get(ctx); + Zb23 = BN_CTX_get(ctx); + if (Zb23 == NULL) goto end; + + /* We have to decide whether + * (X_a/Z_a^2, Y_a/Z_a^3) = (X_b/Z_b^2, Y_b/Z_b^3), + * or equivalently, whether + * (X_a*Z_b^2, Y_a*Z_b^3) = (X_b*Z_a^2, Y_b*Z_a^3). + */ + + if (!b->Z_is_one) + { + if (!field_sqr(group, Zb23, &b->Z, ctx)) goto end; + if (!field_mul(group, tmp1, &a->X, Zb23, ctx)) goto end; + tmp1_ = tmp1; + } + else + tmp1_ = &a->X; + if (!a->Z_is_one) + { + if (!field_sqr(group, Za23, &a->Z, ctx)) goto end; + if (!field_mul(group, tmp2, &b->X, Za23, ctx)) goto end; + tmp2_ = tmp2; + } + else + tmp2_ = &b->X; + + /* compare X_a*Z_b^2 with X_b*Z_a^2 */ + if (BN_cmp(tmp1_, tmp2_) != 0) + { + ret = 1; /* points differ */ + goto end; + } + + + if (!b->Z_is_one) + { + if (!field_mul(group, Zb23, Zb23, &b->Z, ctx)) goto end; + if (!field_mul(group, tmp1, &a->Y, Zb23, ctx)) goto end; + /* tmp1_ = tmp1 */ + } + else + tmp1_ = &a->Y; + if (!a->Z_is_one) + { + if (!field_mul(group, Za23, Za23, &a->Z, ctx)) goto end; + if (!field_mul(group, tmp2, &b->Y, Za23, ctx)) goto end; + /* tmp2_ = tmp2 */ + } + else + tmp2_ = &b->Y; + + /* compare Y_a*Z_b^3 with Y_b*Z_a^3 */ + if (BN_cmp(tmp1_, tmp2_) != 0) + { + ret = 1; /* points differ */ + goto end; + } + + /* points are equal */ + ret = 0; + + end: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *x, *y; + int ret = 0; + + if (point->Z_is_one || EC_POINT_is_at_infinity(group, point)) + return 1; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + x = BN_CTX_get(ctx); + y = BN_CTX_get(ctx); + if (y == NULL) goto err; + + if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) goto err; + if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx)) goto err; + if (!point->Z_is_one) + { + ECerr(EC_F_EC_GFP_SIMPLE_MAKE_AFFINE, ERR_R_INTERNAL_ERROR); + goto err; + } + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + return ret; + } + + +int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT *points[], BN_CTX *ctx) + { + BN_CTX *new_ctx = NULL; + BIGNUM *tmp0, *tmp1; + size_t pow2 = 0; + BIGNUM **heap = NULL; + size_t i; + int ret = 0; + + if (num == 0) + return 1; + + if (ctx == NULL) + { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + return 0; + } + + BN_CTX_start(ctx); + tmp0 = BN_CTX_get(ctx); + tmp1 = BN_CTX_get(ctx); + if (tmp0 == NULL || tmp1 == NULL) goto err; + + /* Before converting the individual points, compute inverses of all Z values. + * Modular inversion is rather slow, but luckily we can do with a single + * explicit inversion, plus about 3 multiplications per input value. + */ + + pow2 = 1; + while (num > pow2) + pow2 <<= 1; + /* Now pow2 is the smallest power of 2 satifsying pow2 >= num. + * We need twice that. */ + pow2 <<= 1; + + heap = OPENSSL_malloc(pow2 * sizeof heap[0]); + if (heap == NULL) goto err; + + /* The array is used as a binary tree, exactly as in heapsort: + * + * heap[1] + * heap[2] heap[3] + * heap[4] heap[5] heap[6] heap[7] + * heap[8]heap[9] heap[10]heap[11] heap[12]heap[13] heap[14] heap[15] + * + * We put the Z's in the last line; + * then we set each other node to the product of its two child-nodes (where + * empty or 0 entries are treated as ones); + * then we invert heap[1]; + * then we invert each other node by replacing it by the product of its + * parent (after inversion) and its sibling (before inversion). + */ + heap[0] = NULL; + for (i = pow2/2 - 1; i > 0; i--) + heap[i] = NULL; + for (i = 0; i < num; i++) + heap[pow2/2 + i] = &points[i]->Z; + for (i = pow2/2 + num; i < pow2; i++) + heap[i] = NULL; + + /* set each node to the product of its children */ + for (i = pow2/2 - 1; i > 0; i--) + { + heap[i] = BN_new(); + if (heap[i] == NULL) goto err; + + if (heap[2*i] != NULL) + { + if ((heap[2*i + 1] == NULL) || BN_is_zero(heap[2*i + 1])) + { + if (!BN_copy(heap[i], heap[2*i])) goto err; + } + else + { + if (BN_is_zero(heap[2*i])) + { + if (!BN_copy(heap[i], heap[2*i + 1])) goto err; + } + else + { + if (!group->meth->field_mul(group, heap[i], + heap[2*i], heap[2*i + 1], ctx)) goto err; + } + } + } + } + + /* invert heap[1] */ + if (!BN_is_zero(heap[1])) + { + if (!BN_mod_inverse(heap[1], heap[1], &group->field, ctx)) + { + ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB); + goto err; + } + } + if (group->meth->field_encode != 0) + { + /* in the Montgomery case, we just turned R*H (representing H) + * into 1/(R*H), but we need R*(1/H) (representing 1/H); + * i.e. we have need to multiply by the Montgomery factor twice */ + if (!group->meth->field_encode(group, heap[1], heap[1], ctx)) goto err; + if (!group->meth->field_encode(group, heap[1], heap[1], ctx)) goto err; + } + + /* set other heap[i]'s to their inverses */ + for (i = 2; i < pow2/2 + num; i += 2) + { + /* i is even */ + if ((heap[i + 1] != NULL) && !BN_is_zero(heap[i + 1])) + { + if (!group->meth->field_mul(group, tmp0, heap[i/2], heap[i + 1], ctx)) goto err; + if (!group->meth->field_mul(group, tmp1, heap[i/2], heap[i], ctx)) goto err; + if (!BN_copy(heap[i], tmp0)) goto err; + if (!BN_copy(heap[i + 1], tmp1)) goto err; + } + else + { + if (!BN_copy(heap[i], heap[i/2])) goto err; + } + } + + /* we have replaced all non-zero Z's by their inverses, now fix up all the points */ + for (i = 0; i < num; i++) + { + EC_POINT *p = points[i]; + + if (!BN_is_zero(&p->Z)) + { + /* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */ + + if (!group->meth->field_sqr(group, tmp1, &p->Z, ctx)) goto err; + if (!group->meth->field_mul(group, &p->X, &p->X, tmp1, ctx)) goto err; + + if (!group->meth->field_mul(group, tmp1, tmp1, &p->Z, ctx)) goto err; + if (!group->meth->field_mul(group, &p->Y, &p->Y, tmp1, ctx)) goto err; + + if (group->meth->field_set_to_one != 0) + { + if (!group->meth->field_set_to_one(group, &p->Z, ctx)) goto err; + } + else + { + if (!BN_one(&p->Z)) goto err; + } + p->Z_is_one = 1; + } + } + + ret = 1; + + err: + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + if (heap != NULL) + { + /* heap[pow2/2] .. heap[pow2-1] have not been allocated locally! */ + for (i = pow2/2 - 1; i > 0; i--) + { + if (heap[i] != NULL) + BN_clear_free(heap[i]); + } + OPENSSL_free(heap); + } + return ret; + } + + +int ec_GFp_simple_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) + { + return BN_mod_mul(r, a, b, &group->field, ctx); + } + + +int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) + { + return BN_mod_sqr(r, a, &group->field, ctx); + } |