|  | /* | 
|  | * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved. | 
|  | * | 
|  | * Licensed under the OpenSSL license (the "License").  You may not use | 
|  | * this file except in compliance with the License.  You can obtain a copy | 
|  | * in the file LICENSE in the source distribution or at | 
|  | * https://www.openssl.org/source/license.html | 
|  | */ | 
|  |  | 
|  | /* ==================================================================== | 
|  | * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED. | 
|  | * | 
|  | * The Elliptic Curve Public-Key Crypto Library (ECC Code) included | 
|  | * herein is developed by SUN MICROSYSTEMS, INC., and is contributed | 
|  | * to the OpenSSL project. | 
|  | * | 
|  | * The ECC Code is licensed pursuant to the OpenSSL open source | 
|  | * license provided below. | 
|  | * | 
|  | * The software is originally written by Sheueling Chang Shantz and | 
|  | * Douglas Stebila of Sun Microsystems Laboratories. | 
|  | * | 
|  | */ | 
|  |  | 
|  | #include <openssl/err.h> | 
|  |  | 
|  | #include "internal/bn_int.h" | 
|  | #include "ec_lcl.h" | 
|  |  | 
|  | #ifndef OPENSSL_NO_EC2M | 
|  |  | 
|  | const EC_METHOD *EC_GF2m_simple_method(void) | 
|  | { | 
|  | static const EC_METHOD ret = { | 
|  | EC_FLAGS_DEFAULT_OCT, | 
|  | NID_X9_62_characteristic_two_field, | 
|  | ec_GF2m_simple_group_init, | 
|  | ec_GF2m_simple_group_finish, | 
|  | ec_GF2m_simple_group_clear_finish, | 
|  | ec_GF2m_simple_group_copy, | 
|  | ec_GF2m_simple_group_set_curve, | 
|  | ec_GF2m_simple_group_get_curve, | 
|  | ec_GF2m_simple_group_get_degree, | 
|  | ec_group_simple_order_bits, | 
|  | ec_GF2m_simple_group_check_discriminant, | 
|  | ec_GF2m_simple_point_init, | 
|  | ec_GF2m_simple_point_finish, | 
|  | ec_GF2m_simple_point_clear_finish, | 
|  | ec_GF2m_simple_point_copy, | 
|  | ec_GF2m_simple_point_set_to_infinity, | 
|  | 0 /* set_Jprojective_coordinates_GFp */ , | 
|  | 0 /* get_Jprojective_coordinates_GFp */ , | 
|  | ec_GF2m_simple_point_set_affine_coordinates, | 
|  | ec_GF2m_simple_point_get_affine_coordinates, | 
|  | 0, 0, 0, | 
|  | ec_GF2m_simple_add, | 
|  | ec_GF2m_simple_dbl, | 
|  | ec_GF2m_simple_invert, | 
|  | ec_GF2m_simple_is_at_infinity, | 
|  | ec_GF2m_simple_is_on_curve, | 
|  | ec_GF2m_simple_cmp, | 
|  | ec_GF2m_simple_make_affine, | 
|  | ec_GF2m_simple_points_make_affine, | 
|  |  | 
|  | /* | 
|  | * the following three method functions are defined in ec2_mult.c | 
|  | */ | 
|  | ec_GF2m_simple_mul, | 
|  | ec_GF2m_precompute_mult, | 
|  | ec_GF2m_have_precompute_mult, | 
|  |  | 
|  | ec_GF2m_simple_field_mul, | 
|  | ec_GF2m_simple_field_sqr, | 
|  | ec_GF2m_simple_field_div, | 
|  | 0 /* field_encode */ , | 
|  | 0 /* field_decode */ , | 
|  | 0,                      /* field_set_to_one */ | 
|  | ec_key_simple_priv2oct, | 
|  | ec_key_simple_oct2priv, | 
|  | 0, /* set private */ | 
|  | ec_key_simple_generate_key, | 
|  | ec_key_simple_check_key, | 
|  | ec_key_simple_generate_public_key, | 
|  | 0, /* keycopy */ | 
|  | 0, /* keyfinish */ | 
|  | ecdh_simple_compute_key | 
|  | }; | 
|  |  | 
|  | return &ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Initialize a GF(2^m)-based EC_GROUP structure. Note that all other members | 
|  | * are handled by EC_GROUP_new. | 
|  | */ | 
|  | int ec_GF2m_simple_group_init(EC_GROUP *group) | 
|  | { | 
|  | group->field = BN_new(); | 
|  | group->a = BN_new(); | 
|  | group->b = BN_new(); | 
|  |  | 
|  | if (group->field == NULL || group->a == NULL || group->b == NULL) { | 
|  | BN_free(group->field); | 
|  | BN_free(group->a); | 
|  | BN_free(group->b); | 
|  | return 0; | 
|  | } | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Free a GF(2^m)-based EC_GROUP structure. Note that all other members are | 
|  | * handled by EC_GROUP_free. | 
|  | */ | 
|  | void ec_GF2m_simple_group_finish(EC_GROUP *group) | 
|  | { | 
|  | BN_free(group->field); | 
|  | BN_free(group->a); | 
|  | BN_free(group->b); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Clear and free a GF(2^m)-based EC_GROUP structure. Note that all other | 
|  | * members are handled by EC_GROUP_clear_free. | 
|  | */ | 
|  | void ec_GF2m_simple_group_clear_finish(EC_GROUP *group) | 
|  | { | 
|  | BN_clear_free(group->field); | 
|  | BN_clear_free(group->a); | 
|  | BN_clear_free(group->b); | 
|  | group->poly[0] = 0; | 
|  | group->poly[1] = 0; | 
|  | group->poly[2] = 0; | 
|  | group->poly[3] = 0; | 
|  | group->poly[4] = 0; | 
|  | group->poly[5] = -1; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Copy a GF(2^m)-based EC_GROUP structure. Note that all other members are | 
|  | * handled by EC_GROUP_copy. | 
|  | */ | 
|  | int ec_GF2m_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->poly[0] = src->poly[0]; | 
|  | dest->poly[1] = src->poly[1]; | 
|  | dest->poly[2] = src->poly[2]; | 
|  | dest->poly[3] = src->poly[3]; | 
|  | dest->poly[4] = src->poly[4]; | 
|  | dest->poly[5] = src->poly[5]; | 
|  | if (bn_wexpand(dest->a, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == | 
|  | NULL) | 
|  | return 0; | 
|  | if (bn_wexpand(dest->b, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) == | 
|  | NULL) | 
|  | return 0; | 
|  | bn_set_all_zero(dest->a); | 
|  | bn_set_all_zero(dest->b); | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* Set the curve parameters of an EC_GROUP structure. */ | 
|  | int ec_GF2m_simple_group_set_curve(EC_GROUP *group, | 
|  | const BIGNUM *p, const BIGNUM *a, | 
|  | const BIGNUM *b, BN_CTX *ctx) | 
|  | { | 
|  | int ret = 0, i; | 
|  |  | 
|  | /* group->field */ | 
|  | if (!BN_copy(group->field, p)) | 
|  | goto err; | 
|  | i = BN_GF2m_poly2arr(group->field, group->poly, 6) - 1; | 
|  | if ((i != 5) && (i != 3)) { | 
|  | ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, EC_R_UNSUPPORTED_FIELD); | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | /* group->a */ | 
|  | if (!BN_GF2m_mod_arr(group->a, a, group->poly)) | 
|  | goto err; | 
|  | if (bn_wexpand(group->a, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2) | 
|  | == NULL) | 
|  | goto err; | 
|  | bn_set_all_zero(group->a); | 
|  |  | 
|  | /* group->b */ | 
|  | if (!BN_GF2m_mod_arr(group->b, b, group->poly)) | 
|  | goto err; | 
|  | if (bn_wexpand(group->b, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2) | 
|  | == NULL) | 
|  | goto err; | 
|  | bn_set_all_zero(group->b); | 
|  |  | 
|  | ret = 1; | 
|  | err: | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Get the curve parameters of an EC_GROUP structure. If p, a, or b are NULL | 
|  | * then there values will not be set but the method will return with success. | 
|  | */ | 
|  | int ec_GF2m_simple_group_get_curve(const EC_GROUP *group, BIGNUM *p, | 
|  | BIGNUM *a, BIGNUM *b, BN_CTX *ctx) | 
|  | { | 
|  | int ret = 0; | 
|  |  | 
|  | if (p != NULL) { | 
|  | if (!BN_copy(p, group->field)) | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | 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: | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Gets the degree of the field.  For a curve over GF(2^m) this is the value | 
|  | * m. | 
|  | */ | 
|  | int ec_GF2m_simple_group_get_degree(const EC_GROUP *group) | 
|  | { | 
|  | return BN_num_bits(group->field) - 1; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Checks the discriminant of the curve. y^2 + x*y = x^3 + a*x^2 + b is an | 
|  | * elliptic curve <=> b != 0 (mod p) | 
|  | */ | 
|  | int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *group, | 
|  | BN_CTX *ctx) | 
|  | { | 
|  | int ret = 0; | 
|  | BIGNUM *b; | 
|  | BN_CTX *new_ctx = NULL; | 
|  |  | 
|  | if (ctx == NULL) { | 
|  | ctx = new_ctx = BN_CTX_new(); | 
|  | if (ctx == NULL) { | 
|  | ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT, | 
|  | ERR_R_MALLOC_FAILURE); | 
|  | goto err; | 
|  | } | 
|  | } | 
|  | BN_CTX_start(ctx); | 
|  | b = BN_CTX_get(ctx); | 
|  | if (b == NULL) | 
|  | goto err; | 
|  |  | 
|  | if (!BN_GF2m_mod_arr(b, group->b, group->poly)) | 
|  | goto err; | 
|  |  | 
|  | /* | 
|  | * check the discriminant: y^2 + x*y = x^3 + a*x^2 + b is an elliptic | 
|  | * curve <=> b != 0 (mod p) | 
|  | */ | 
|  | if (BN_is_zero(b)) | 
|  | goto err; | 
|  |  | 
|  | ret = 1; | 
|  |  | 
|  | err: | 
|  | if (ctx != NULL) | 
|  | BN_CTX_end(ctx); | 
|  | BN_CTX_free(new_ctx); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* Initializes an EC_POINT. */ | 
|  | int ec_GF2m_simple_point_init(EC_POINT *point) | 
|  | { | 
|  | point->X = BN_new(); | 
|  | point->Y = BN_new(); | 
|  | point->Z = BN_new(); | 
|  |  | 
|  | if (point->X == NULL || point->Y == NULL || point->Z == NULL) { | 
|  | BN_free(point->X); | 
|  | BN_free(point->Y); | 
|  | BN_free(point->Z); | 
|  | return 0; | 
|  | } | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* Frees an EC_POINT. */ | 
|  | void ec_GF2m_simple_point_finish(EC_POINT *point) | 
|  | { | 
|  | BN_free(point->X); | 
|  | BN_free(point->Y); | 
|  | BN_free(point->Z); | 
|  | } | 
|  |  | 
|  | /* Clears and frees an EC_POINT. */ | 
|  | void ec_GF2m_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; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Copy the contents of one EC_POINT into another.  Assumes dest is | 
|  | * initialized. | 
|  | */ | 
|  | int ec_GF2m_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; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Set an EC_POINT to the point at infinity. A point at infinity is | 
|  | * represented by having Z=0. | 
|  | */ | 
|  | int ec_GF2m_simple_point_set_to_infinity(const EC_GROUP *group, | 
|  | EC_POINT *point) | 
|  | { | 
|  | point->Z_is_one = 0; | 
|  | BN_zero(point->Z); | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Set the coordinates of an EC_POINT using affine coordinates. Note that | 
|  | * the simple implementation only uses affine coordinates. | 
|  | */ | 
|  | int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *group, | 
|  | EC_POINT *point, | 
|  | const BIGNUM *x, | 
|  | const BIGNUM *y, BN_CTX *ctx) | 
|  | { | 
|  | int ret = 0; | 
|  | if (x == NULL || y == NULL) { | 
|  | ECerr(EC_F_EC_GF2M_SIMPLE_POINT_SET_AFFINE_COORDINATES, | 
|  | ERR_R_PASSED_NULL_PARAMETER); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | if (!BN_copy(point->X, x)) | 
|  | goto err; | 
|  | BN_set_negative(point->X, 0); | 
|  | if (!BN_copy(point->Y, y)) | 
|  | goto err; | 
|  | BN_set_negative(point->Y, 0); | 
|  | if (!BN_copy(point->Z, BN_value_one())) | 
|  | goto err; | 
|  | BN_set_negative(point->Z, 0); | 
|  | point->Z_is_one = 1; | 
|  | ret = 1; | 
|  |  | 
|  | err: | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Gets the affine coordinates of an EC_POINT. Note that the simple | 
|  | * implementation only uses affine coordinates. | 
|  | */ | 
|  | int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group, | 
|  | const EC_POINT *point, | 
|  | BIGNUM *x, BIGNUM *y, | 
|  | BN_CTX *ctx) | 
|  | { | 
|  | int ret = 0; | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, point)) { | 
|  | ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, | 
|  | EC_R_POINT_AT_INFINITY); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | if (BN_cmp(point->Z, BN_value_one())) { | 
|  | ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES, | 
|  | ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); | 
|  | return 0; | 
|  | } | 
|  | if (x != NULL) { | 
|  | if (!BN_copy(x, point->X)) | 
|  | goto err; | 
|  | BN_set_negative(x, 0); | 
|  | } | 
|  | if (y != NULL) { | 
|  | if (!BN_copy(y, point->Y)) | 
|  | goto err; | 
|  | BN_set_negative(y, 0); | 
|  | } | 
|  | ret = 1; | 
|  |  | 
|  | err: | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Computes a + b and stores the result in r.  r could be a or b, a could be | 
|  | * b. Uses algorithm A.10.2 of IEEE P1363. | 
|  | */ | 
|  | int ec_GF2m_simple_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | 
|  | const EC_POINT *b, BN_CTX *ctx) | 
|  | { | 
|  | BN_CTX *new_ctx = NULL; | 
|  | BIGNUM *x0, *y0, *x1, *y1, *x2, *y2, *s, *t; | 
|  | int ret = 0; | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, a)) { | 
|  | if (!EC_POINT_copy(r, b)) | 
|  | return 0; | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, b)) { | 
|  | if (!EC_POINT_copy(r, a)) | 
|  | return 0; | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | if (ctx == NULL) { | 
|  | ctx = new_ctx = BN_CTX_new(); | 
|  | if (ctx == NULL) | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | BN_CTX_start(ctx); | 
|  | x0 = BN_CTX_get(ctx); | 
|  | y0 = BN_CTX_get(ctx); | 
|  | x1 = BN_CTX_get(ctx); | 
|  | y1 = BN_CTX_get(ctx); | 
|  | x2 = BN_CTX_get(ctx); | 
|  | y2 = BN_CTX_get(ctx); | 
|  | s = BN_CTX_get(ctx); | 
|  | t = BN_CTX_get(ctx); | 
|  | if (t == NULL) | 
|  | goto err; | 
|  |  | 
|  | if (a->Z_is_one) { | 
|  | if (!BN_copy(x0, a->X)) | 
|  | goto err; | 
|  | if (!BN_copy(y0, a->Y)) | 
|  | goto err; | 
|  | } else { | 
|  | if (!EC_POINT_get_affine_coordinates_GF2m(group, a, x0, y0, ctx)) | 
|  | goto err; | 
|  | } | 
|  | if (b->Z_is_one) { | 
|  | if (!BN_copy(x1, b->X)) | 
|  | goto err; | 
|  | if (!BN_copy(y1, b->Y)) | 
|  | goto err; | 
|  | } else { | 
|  | if (!EC_POINT_get_affine_coordinates_GF2m(group, b, x1, y1, ctx)) | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | if (BN_GF2m_cmp(x0, x1)) { | 
|  | if (!BN_GF2m_add(t, x0, x1)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(s, y0, y1)) | 
|  | goto err; | 
|  | if (!group->meth->field_div(group, s, s, t, ctx)) | 
|  | goto err; | 
|  | if (!group->meth->field_sqr(group, x2, s, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(x2, x2, group->a)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(x2, x2, s)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(x2, x2, t)) | 
|  | goto err; | 
|  | } else { | 
|  | if (BN_GF2m_cmp(y0, y1) || BN_is_zero(x1)) { | 
|  | if (!EC_POINT_set_to_infinity(group, r)) | 
|  | goto err; | 
|  | ret = 1; | 
|  | goto err; | 
|  | } | 
|  | if (!group->meth->field_div(group, s, y1, x1, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(s, s, x1)) | 
|  | goto err; | 
|  |  | 
|  | if (!group->meth->field_sqr(group, x2, s, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(x2, x2, s)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(x2, x2, group->a)) | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | if (!BN_GF2m_add(y2, x1, x2)) | 
|  | goto err; | 
|  | if (!group->meth->field_mul(group, y2, y2, s, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(y2, y2, x2)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(y2, y2, y1)) | 
|  | goto err; | 
|  |  | 
|  | if (!EC_POINT_set_affine_coordinates_GF2m(group, r, x2, y2, ctx)) | 
|  | goto err; | 
|  |  | 
|  | ret = 1; | 
|  |  | 
|  | err: | 
|  | BN_CTX_end(ctx); | 
|  | BN_CTX_free(new_ctx); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Computes 2 * a and stores the result in r.  r could be a. Uses algorithm | 
|  | * A.10.2 of IEEE P1363. | 
|  | */ | 
|  | int ec_GF2m_simple_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, | 
|  | BN_CTX *ctx) | 
|  | { | 
|  | return ec_GF2m_simple_add(group, r, a, a, ctx); | 
|  | } | 
|  |  | 
|  | int ec_GF2m_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; | 
|  |  | 
|  | if (!EC_POINT_make_affine(group, point, ctx)) | 
|  | return 0; | 
|  | return BN_GF2m_add(point->Y, point->X, point->Y); | 
|  | } | 
|  |  | 
|  | /* Indicates whether the given point is the point at infinity. */ | 
|  | int ec_GF2m_simple_is_at_infinity(const EC_GROUP *group, | 
|  | const EC_POINT *point) | 
|  | { | 
|  | return BN_is_zero(point->Z); | 
|  | } | 
|  |  | 
|  | /*- | 
|  | * Determines whether the given EC_POINT is an actual point on the curve defined | 
|  | * in the EC_GROUP.  A point is valid if it satisfies the Weierstrass equation: | 
|  | *      y^2 + x*y = x^3 + a*x^2 + b. | 
|  | */ | 
|  | int ec_GF2m_simple_is_on_curve(const EC_GROUP *group, const EC_POINT *point, | 
|  | BN_CTX *ctx) | 
|  | { | 
|  | int ret = -1; | 
|  | BN_CTX *new_ctx = NULL; | 
|  | BIGNUM *lh, *y2; | 
|  | int (*field_mul) (const EC_GROUP *, BIGNUM *, const BIGNUM *, | 
|  | const BIGNUM *, BN_CTX *); | 
|  | int (*field_sqr) (const EC_GROUP *, BIGNUM *, const BIGNUM *, BN_CTX *); | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, point)) | 
|  | return 1; | 
|  |  | 
|  | field_mul = group->meth->field_mul; | 
|  | field_sqr = group->meth->field_sqr; | 
|  |  | 
|  | /* only support affine coordinates */ | 
|  | if (!point->Z_is_one) | 
|  | return -1; | 
|  |  | 
|  | if (ctx == NULL) { | 
|  | ctx = new_ctx = BN_CTX_new(); | 
|  | if (ctx == NULL) | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | BN_CTX_start(ctx); | 
|  | y2 = BN_CTX_get(ctx); | 
|  | lh = BN_CTX_get(ctx); | 
|  | if (lh == NULL) | 
|  | goto err; | 
|  |  | 
|  | /*- | 
|  | * We have a curve defined by a Weierstrass equation | 
|  | *      y^2 + x*y = x^3 + a*x^2 + b. | 
|  | *  <=> x^3 + a*x^2 + x*y + b + y^2 = 0 | 
|  | *  <=> ((x + a) * x + y ) * x + b + y^2 = 0 | 
|  | */ | 
|  | if (!BN_GF2m_add(lh, point->X, group->a)) | 
|  | goto err; | 
|  | if (!field_mul(group, lh, lh, point->X, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(lh, lh, point->Y)) | 
|  | goto err; | 
|  | if (!field_mul(group, lh, lh, point->X, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(lh, lh, group->b)) | 
|  | goto err; | 
|  | if (!field_sqr(group, y2, point->Y, ctx)) | 
|  | goto err; | 
|  | if (!BN_GF2m_add(lh, lh, y2)) | 
|  | goto err; | 
|  | ret = BN_is_zero(lh); | 
|  | err: | 
|  | if (ctx) | 
|  | BN_CTX_end(ctx); | 
|  | BN_CTX_free(new_ctx); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /*- | 
|  | * Indicates whether two points are equal. | 
|  | * Return values: | 
|  | *  -1   error | 
|  | *   0   equal (in affine coordinates) | 
|  | *   1   not equal | 
|  | */ | 
|  | int ec_GF2m_simple_cmp(const EC_GROUP *group, const EC_POINT *a, | 
|  | const EC_POINT *b, BN_CTX *ctx) | 
|  | { | 
|  | BIGNUM *aX, *aY, *bX, *bY; | 
|  | BN_CTX *new_ctx = NULL; | 
|  | int ret = -1; | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, a)) { | 
|  | return EC_POINT_is_at_infinity(group, b) ? 0 : 1; | 
|  | } | 
|  |  | 
|  | if (EC_POINT_is_at_infinity(group, b)) | 
|  | return 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; | 
|  | } | 
|  |  | 
|  | if (ctx == NULL) { | 
|  | ctx = new_ctx = BN_CTX_new(); | 
|  | if (ctx == NULL) | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | BN_CTX_start(ctx); | 
|  | aX = BN_CTX_get(ctx); | 
|  | aY = BN_CTX_get(ctx); | 
|  | bX = BN_CTX_get(ctx); | 
|  | bY = BN_CTX_get(ctx); | 
|  | if (bY == NULL) | 
|  | goto err; | 
|  |  | 
|  | if (!EC_POINT_get_affine_coordinates_GF2m(group, a, aX, aY, ctx)) | 
|  | goto err; | 
|  | if (!EC_POINT_get_affine_coordinates_GF2m(group, b, bX, bY, ctx)) | 
|  | goto err; | 
|  | ret = ((BN_cmp(aX, bX) == 0) && BN_cmp(aY, bY) == 0) ? 0 : 1; | 
|  |  | 
|  | err: | 
|  | if (ctx) | 
|  | BN_CTX_end(ctx); | 
|  | BN_CTX_free(new_ctx); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* Forces the given EC_POINT to internally use affine coordinates. */ | 
|  | int ec_GF2m_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_GF2m(group, point, x, y, ctx)) | 
|  | goto err; | 
|  | if (!BN_copy(point->X, x)) | 
|  | goto err; | 
|  | if (!BN_copy(point->Y, y)) | 
|  | goto err; | 
|  | if (!BN_one(point->Z)) | 
|  | goto err; | 
|  | point->Z_is_one = 1; | 
|  |  | 
|  | ret = 1; | 
|  |  | 
|  | err: | 
|  | if (ctx) | 
|  | BN_CTX_end(ctx); | 
|  | BN_CTX_free(new_ctx); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Forces each of the EC_POINTs in the given array to use affine coordinates. | 
|  | */ | 
|  | int ec_GF2m_simple_points_make_affine(const EC_GROUP *group, size_t num, | 
|  | EC_POINT *points[], BN_CTX *ctx) | 
|  | { | 
|  | size_t i; | 
|  |  | 
|  | for (i = 0; i < num; i++) { | 
|  | if (!group->meth->make_affine(group, points[i], ctx)) | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* Wrapper to simple binary polynomial field multiplication implementation. */ | 
|  | int ec_GF2m_simple_field_mul(const EC_GROUP *group, BIGNUM *r, | 
|  | const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) | 
|  | { | 
|  | return BN_GF2m_mod_mul_arr(r, a, b, group->poly, ctx); | 
|  | } | 
|  |  | 
|  | /* Wrapper to simple binary polynomial field squaring implementation. */ | 
|  | int ec_GF2m_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, | 
|  | const BIGNUM *a, BN_CTX *ctx) | 
|  | { | 
|  | return BN_GF2m_mod_sqr_arr(r, a, group->poly, ctx); | 
|  | } | 
|  |  | 
|  | /* Wrapper to simple binary polynomial field division implementation. */ | 
|  | int ec_GF2m_simple_field_div(const EC_GROUP *group, BIGNUM *r, | 
|  | const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) | 
|  | { | 
|  | return BN_GF2m_mod_div(r, a, b, group->field, ctx); | 
|  | } | 
|  |  | 
|  | #endif |