[thirdparty/openssl.git] / crypto / ec / ec2_smpl.c

/*
 * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2002, Oracle and/or its affiliates. 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
 */

#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,
        0 /* mul */,
        0 /* precompute_mul */,
        0 /* have_precompute_mul */,
        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:
    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:
    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:
    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
Commit	Line	Data
4f22f405 RS	1	/*
4f22f405 RS	2	* Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
aa8f3d76	3	* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4f22f405 RS	4	*
	5	* Licensed under the OpenSSL license (the "License"). You may not use
	6	* this file except in compliance with the License. You can obtain a copy
	7	* in the file LICENSE in the source distribution or at
	8	* https://www.openssl.org/source/license.html
	9	*/
	10
7793f30e BM	11	#include <openssl/err.h>
7793f30e BM	12
5784a521	13	#include "internal/bn_int.h"
7793f30e BM	14	#include "ec_lcl.h"
7793f30e BM	15
b3310161 DSH	16	#ifndef OPENSSL_NO_EC2M
b3310161 DSH	17
7793f30e	18	const EC_METHOD *EC_GF2m_simple_method(void)
0f113f3e MC	19	{
	20	static const EC_METHOD ret = {
	21	EC_FLAGS_DEFAULT_OCT,
	22	NID_X9_62_characteristic_two_field,
	23	ec_GF2m_simple_group_init,
	24	ec_GF2m_simple_group_finish,
	25	ec_GF2m_simple_group_clear_finish,
	26	ec_GF2m_simple_group_copy,
	27	ec_GF2m_simple_group_set_curve,
	28	ec_GF2m_simple_group_get_curve,
	29	ec_GF2m_simple_group_get_degree,
9ff9bccc	30	ec_group_simple_order_bits,
0f113f3e MC	31	ec_GF2m_simple_group_check_discriminant,
	32	ec_GF2m_simple_point_init,
	33	ec_GF2m_simple_point_finish,
	34	ec_GF2m_simple_point_clear_finish,
	35	ec_GF2m_simple_point_copy,
	36	ec_GF2m_simple_point_set_to_infinity,
	37	0 /* set_Jprojective_coordinates_GFp */ ,
	38	0 /* get_Jprojective_coordinates_GFp */ ,
	39	ec_GF2m_simple_point_set_affine_coordinates,
	40	ec_GF2m_simple_point_get_affine_coordinates,
	41	0, 0, 0,
	42	ec_GF2m_simple_add,
	43	ec_GF2m_simple_dbl,
	44	ec_GF2m_simple_invert,
	45	ec_GF2m_simple_is_at_infinity,
	46	ec_GF2m_simple_is_on_curve,
	47	ec_GF2m_simple_cmp,
	48	ec_GF2m_simple_make_affine,
	49	ec_GF2m_simple_points_make_affine,
a7b0b69c BB	50	0 /* mul */,
	51	0 /* precompute_mul */,
	52	0 /* have_precompute_mul */,
0f113f3e MC	53	ec_GF2m_simple_field_mul,
	54	ec_GF2m_simple_field_sqr,
	55	ec_GF2m_simple_field_div,
	56	0 /* field_encode */ ,
	57	0 /* field_decode */ ,
9ff9bccc DSH	58	0, /* field_set_to_one */
	59	ec_key_simple_priv2oct,
	60	ec_key_simple_oct2priv,
	61	0, /* set private */
	62	ec_key_simple_generate_key,
	63	ec_key_simple_check_key,
	64	ec_key_simple_generate_public_key,
	65	0, /* keycopy */
	66	0, /* keyfinish */
	67	ecdh_simple_compute_key
0f113f3e MC	68	};
	69
	70	return &ret;
	71	}
	72
	73	/*
	74	* Initialize a GF(2^m)-based EC_GROUP structure. Note that all other members
	75	* are handled by EC_GROUP_new.
7793f30e BM	76	*/
7793f30e BM	77	int ec_GF2m_simple_group_init(EC_GROUP *group)
0f113f3e MC	78	{
	79	group->field = BN_new();
	80	group->a = BN_new();
	81	group->b = BN_new();
	82
90945fa3	83	if (group->field == NULL \|\| group->a == NULL \|\| group->b == NULL) {
23a1d5e9 RS	84	BN_free(group->field);
	85	BN_free(group->a);
	86	BN_free(group->b);
0f113f3e MC	87	return 0;
	88	}
	89	return 1;
	90	}
	91
	92	/*
	93	* Free a GF(2^m)-based EC_GROUP structure. Note that all other members are
	94	* handled by EC_GROUP_free.
7793f30e BM	95	*/
7793f30e BM	96	void ec_GF2m_simple_group_finish(EC_GROUP *group)
0f113f3e MC	97	{
	98	BN_free(group->field);
	99	BN_free(group->a);
	100	BN_free(group->b);
	101	}
	102
	103	/*
	104	* Clear and free a GF(2^m)-based EC_GROUP structure. Note that all other
	105	* members are handled by EC_GROUP_clear_free.
7793f30e BM	106	*/
7793f30e BM	107	void ec_GF2m_simple_group_clear_finish(EC_GROUP *group)
0f113f3e MC	108	{
	109	BN_clear_free(group->field);
	110	BN_clear_free(group->a);
	111	BN_clear_free(group->b);
	112	group->poly[0] = 0;
	113	group->poly[1] = 0;
	114	group->poly[2] = 0;
	115	group->poly[3] = 0;
	116	group->poly[4] = 0;
	117	group->poly[5] = -1;
	118	}
	119
	120	/*
	121	* Copy a GF(2^m)-based EC_GROUP structure. Note that all other members are
	122	* handled by EC_GROUP_copy.
7793f30e BM	123	*/
7793f30e BM	124	int ec_GF2m_simple_group_copy(EC_GROUP dest, const EC_GROUP src)
0f113f3e MC	125	{
	126	if (!BN_copy(dest->field, src->field))
	127	return 0;
	128	if (!BN_copy(dest->a, src->a))
	129	return 0;
	130	if (!BN_copy(dest->b, src->b))
	131	return 0;
	132	dest->poly[0] = src->poly[0];
	133	dest->poly[1] = src->poly[1];
	134	dest->poly[2] = src->poly[2];
	135	dest->poly[3] = src->poly[3];
	136	dest->poly[4] = src->poly[4];
	137	dest->poly[5] = src->poly[5];
	138	if (bn_wexpand(dest->a, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) ==
	139	NULL)
	140	return 0;
	141	if (bn_wexpand(dest->b, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2) ==
	142	NULL)
	143	return 0;
	144	bn_set_all_zero(dest->a);
	145	bn_set_all_zero(dest->b);
	146	return 1;
	147	}
7793f30e BM	148
7793f30e BM	149	/* Set the curve parameters of an EC_GROUP structure. */
35b73a1f	150	int ec_GF2m_simple_group_set_curve(EC_GROUP *group,
0f113f3e MC	151	const BIGNUM p, const BIGNUM a,
	152	const BIGNUM b, BN_CTX ctx)
	153	{
	154	int ret = 0, i;
	155
	156	/* group->field */
	157	if (!BN_copy(group->field, p))
	158	goto err;
	159	i = BN_GF2m_poly2arr(group->field, group->poly, 6) - 1;
	160	if ((i != 5) && (i != 3)) {
	161	ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, EC_R_UNSUPPORTED_FIELD);
	162	goto err;
	163	}
	164
	165	/* group->a */
	166	if (!BN_GF2m_mod_arr(group->a, a, group->poly))
	167	goto err;
	168	if (bn_wexpand(group->a, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2)
	169	== NULL)
	170	goto err;
	171	bn_set_all_zero(group->a);
	172
	173	/* group->b */
	174	if (!BN_GF2m_mod_arr(group->b, b, group->poly))
	175	goto err;
	176	if (bn_wexpand(group->b, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2)
	177	== NULL)
	178	goto err;
	179	bn_set_all_zero(group->b);
	180
	181	ret = 1;
	182	err:
	183	return ret;
	184	}
	185
	186	/*
	187	* Get the curve parameters of an EC_GROUP structure. If p, a, or b are NULL
	188	* then there values will not be set but the method will return with success.
7793f30e	189	*/
0f113f3e MC	190	int ec_GF2m_simple_group_get_curve(const EC_GROUP group, BIGNUM p,
	191	BIGNUM a, BIGNUM b, BN_CTX *ctx)
	192	{
	193	int ret = 0;
	194
	195	if (p != NULL) {
	196	if (!BN_copy(p, group->field))
	197	return 0;
	198	}
	199
	200	if (a != NULL) {
	201	if (!BN_copy(a, group->a))
	202	goto err;
	203	}
7793f30e	204
0f113f3e MC	205	if (b != NULL) {
	206	if (!BN_copy(b, group->b))
	207	goto err;
	208	}
7793f30e	209
0f113f3e MC	210	ret = 1;
	211
	212	err:
	213	return ret;
	214	}
	215
	216	/*
	217	* Gets the degree of the field. For a curve over GF(2^m) this is the value
	218	* m.
	219	*/
	220	int ec_GF2m_simple_group_get_degree(const EC_GROUP *group)
	221	{
	222	return BN_num_bits(group->field) - 1;
	223	}
	224
	225	/*
	226	* Checks the discriminant of the curve. y^2 + xy = x^3 + ax^2 + b is an
	227	* elliptic curve <=> b != 0 (mod p)
7793f30e	228	*/
0f113f3e MC	229	int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *group,
	230	BN_CTX *ctx)
	231	{
	232	int ret = 0;
	233	BIGNUM *b;
	234	BN_CTX *new_ctx = NULL;
	235
	236	if (ctx == NULL) {
	237	ctx = new_ctx = BN_CTX_new();
	238	if (ctx == NULL) {
	239	ECerr(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT,
	240	ERR_R_MALLOC_FAILURE);
	241	goto err;
	242	}
	243	}
	244	BN_CTX_start(ctx);
	245	b = BN_CTX_get(ctx);
	246	if (b == NULL)
	247	goto err;
	248
	249	if (!BN_GF2m_mod_arr(b, group->b, group->poly))
	250	goto err;
	251
	252	/*
	253	* check the discriminant: y^2 + xy = x^3 + ax^2 + b is an elliptic
	254	* curve <=> b != 0 (mod p)
	255	*/
	256	if (BN_is_zero(b))
	257	goto err;
	258
	259	ret = 1;
7793f30e	260
0f113f3e MC	261	err:
	262	if (ctx != NULL)
	263	BN_CTX_end(ctx);
23a1d5e9	264	BN_CTX_free(new_ctx);
0f113f3e MC	265	return ret;
0f113f3e MC	266	}
7793f30e BM	267
	268	/* Initializes an EC_POINT. */
	269	int ec_GF2m_simple_point_init(EC_POINT *point)
0f113f3e MC	270	{
	271	point->X = BN_new();
	272	point->Y = BN_new();
	273	point->Z = BN_new();
	274
90945fa3	275	if (point->X == NULL \|\| point->Y == NULL \|\| point->Z == NULL) {
23a1d5e9 RS	276	BN_free(point->X);
	277	BN_free(point->Y);
	278	BN_free(point->Z);
0f113f3e MC	279	return 0;
	280	}
	281	return 1;
	282	}
7793f30e BM	283
	284	/* Frees an EC_POINT. */
	285	void ec_GF2m_simple_point_finish(EC_POINT *point)
0f113f3e MC	286	{
	287	BN_free(point->X);
	288	BN_free(point->Y);
	289	BN_free(point->Z);
	290	}
7793f30e BM	291
	292	/* Clears and frees an EC_POINT. */
	293	void ec_GF2m_simple_point_clear_finish(EC_POINT *point)
0f113f3e MC	294	{
	295	BN_clear_free(point->X);
	296	BN_clear_free(point->Y);
	297	BN_clear_free(point->Z);
	298	point->Z_is_one = 0;
	299	}
	300
	301	/*
	302	* Copy the contents of one EC_POINT into another. Assumes dest is
	303	* initialized.
7793f30e	304	*/
0f113f3e MC	305	int ec_GF2m_simple_point_copy(EC_POINT dest, const EC_POINT src)
	306	{
	307	if (!BN_copy(dest->X, src->X))
	308	return 0;
	309	if (!BN_copy(dest->Y, src->Y))
	310	return 0;
	311	if (!BN_copy(dest->Z, src->Z))
	312	return 0;
	313	dest->Z_is_one = src->Z_is_one;
	314
	315	return 1;
	316	}
	317
	318	/*
	319	* Set an EC_POINT to the point at infinity. A point at infinity is
	320	* represented by having Z=0.
7793f30e	321	*/
0f113f3e MC	322	int ec_GF2m_simple_point_set_to_infinity(const EC_GROUP *group,
	323	EC_POINT *point)
	324	{
	325	point->Z_is_one = 0;
	326	BN_zero(point->Z);
	327	return 1;
	328	}
	329
	330	/*
	331	* Set the coordinates of an EC_POINT using affine coordinates. Note that
	332	* the simple implementation only uses affine coordinates.
7793f30e	333	*/
0f113f3e MC	334	int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *group,
	335	EC_POINT *point,
	336	const BIGNUM *x,
	337	const BIGNUM y, BN_CTX ctx)
	338	{
	339	int ret = 0;
	340	if (x == NULL \|\| y == NULL) {
	341	ECerr(EC_F_EC_GF2M_SIMPLE_POINT_SET_AFFINE_COORDINATES,
	342	ERR_R_PASSED_NULL_PARAMETER);
	343	return 0;
	344	}
	345
	346	if (!BN_copy(point->X, x))
	347	goto err;
	348	BN_set_negative(point->X, 0);
	349	if (!BN_copy(point->Y, y))
	350	goto err;
	351	BN_set_negative(point->Y, 0);
	352	if (!BN_copy(point->Z, BN_value_one()))
	353	goto err;
	354	BN_set_negative(point->Z, 0);
	355	point->Z_is_one = 1;
	356	ret = 1;
	357
7793f30e	358	err:
0f113f3e MC	359	return ret;
0f113f3e MC	360	}
7793f30e	361
0f113f3e MC	362	/*
	363	* Gets the affine coordinates of an EC_POINT. Note that the simple
	364	* implementation only uses affine coordinates.
7793f30e	365	*/
0f113f3e MC	366	int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *group,
	367	const EC_POINT *point,
	368	BIGNUM x, BIGNUM y,
	369	BN_CTX *ctx)
	370	{
	371	int ret = 0;
	372
	373	if (EC_POINT_is_at_infinity(group, point)) {
	374	ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES,
	375	EC_R_POINT_AT_INFINITY);
	376	return 0;
	377	}
	378
	379	if (BN_cmp(point->Z, BN_value_one())) {
	380	ECerr(EC_F_EC_GF2M_SIMPLE_POINT_GET_AFFINE_COORDINATES,
	381	ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
	382	return 0;
	383	}
	384	if (x != NULL) {
	385	if (!BN_copy(x, point->X))
	386	goto err;
	387	BN_set_negative(x, 0);
	388	}
	389	if (y != NULL) {
	390	if (!BN_copy(y, point->Y))
	391	goto err;
	392	BN_set_negative(y, 0);
	393	}
	394	ret = 1;
7793f30e BM	395
7793f30e BM	396	err:
0f113f3e MC	397	return ret;
0f113f3e MC	398	}
7793f30e	399
0f113f3e MC	400	/*
	401	* Computes a + b and stores the result in r. r could be a or b, a could be
	402	* b. Uses algorithm A.10.2 of IEEE P1363.
7793f30e	403	*/
0f113f3e MC	404	int ec_GF2m_simple_add(const EC_GROUP group, EC_POINT r, const EC_POINT *a,
	405	const EC_POINT b, BN_CTX ctx)
	406	{
	407	BN_CTX *new_ctx = NULL;
	408	BIGNUM x0, y0, x1, y1, x2, y2, s, t;
	409	int ret = 0;
	410
	411	if (EC_POINT_is_at_infinity(group, a)) {
	412	if (!EC_POINT_copy(r, b))
	413	return 0;
	414	return 1;
	415	}
	416
	417	if (EC_POINT_is_at_infinity(group, b)) {
	418	if (!EC_POINT_copy(r, a))
	419	return 0;
	420	return 1;
	421	}
	422
	423	if (ctx == NULL) {
	424	ctx = new_ctx = BN_CTX_new();
	425	if (ctx == NULL)
	426	return 0;
	427	}
	428
	429	BN_CTX_start(ctx);
	430	x0 = BN_CTX_get(ctx);
	431	y0 = BN_CTX_get(ctx);
	432	x1 = BN_CTX_get(ctx);
	433	y1 = BN_CTX_get(ctx);
	434	x2 = BN_CTX_get(ctx);
	435	y2 = BN_CTX_get(ctx);
	436	s = BN_CTX_get(ctx);
	437	t = BN_CTX_get(ctx);
	438	if (t == NULL)
	439	goto err;
	440
	441	if (a->Z_is_one) {
	442	if (!BN_copy(x0, a->X))
	443	goto err;
	444	if (!BN_copy(y0, a->Y))
	445	goto err;
	446	} else {
	447	if (!EC_POINT_get_affine_coordinates_GF2m(group, a, x0, y0, ctx))
	448	goto err;
	449	}
	450	if (b->Z_is_one) {
	451	if (!BN_copy(x1, b->X))
	452	goto err;
	453	if (!BN_copy(y1, b->Y))
	454	goto err;
	455	} else {
	456	if (!EC_POINT_get_affine_coordinates_GF2m(group, b, x1, y1, ctx))
	457	goto err;
	458	}
	459
	460	if (BN_GF2m_cmp(x0, x1)) {
	461	if (!BN_GF2m_add(t, x0, x1))
	462	goto err;
	463	if (!BN_GF2m_add(s, y0, y1))
	464	goto err;
	465	if (!group->meth->field_div(group, s, s, t, ctx))
	466	goto err;
	467	if (!group->meth->field_sqr(group, x2, s, ctx))
468	goto err;
469	if (!BN_GF2m_add(x2, x2, group->a))
470	goto err;
471	if (!BN_GF2m_add(x2, x2, s))
472	goto err;
473	if (!BN_GF2m_add(x2, x2, t))
474	goto err;
475	} else {
476	if (BN_GF2m_cmp(y0, y1) \|\| BN_is_zero(x1)) {
477	if (!EC_POINT_set_to_infinity(group, r))
478	goto err;
479	ret = 1;
480	goto err;
481	}
482	if (!group->meth->field_div(group, s, y1, x1, ctx))
483	goto err;
484	if (!BN_GF2m_add(s, s, x1))
485	goto err;
486
487	if (!group->meth->field_sqr(group, x2, s, ctx))
488	goto err;
489	if (!BN_GF2m_add(x2, x2, s))
490	goto err;
491	if (!BN_GF2m_add(x2, x2, group->a))
492	goto err;
493	}
494
495	if (!BN_GF2m_add(y2, x1, x2))
496	goto err;
497	if (!group->meth->field_mul(group, y2, y2, s, ctx))
498	goto err;
499	if (!BN_GF2m_add(y2, y2, x2))
500	goto err;
501	if (!BN_GF2m_add(y2, y2, y1))
502	goto err;
503
504	if (!EC_POINT_set_affine_coordinates_GF2m(group, r, x2, y2, ctx))
505	goto err;
506
507	ret = 1;
7793f30e	508
0f113f3e MC	509	err:
0f113f3e MC	510	BN_CTX_end(ctx);
23a1d5e9	511	BN_CTX_free(new_ctx);
0f113f3e MC	512	return ret;
	513	}
	514
	515	/*
	516	* Computes 2 * a and stores the result in r. r could be a. Uses algorithm
	517	* A.10.2 of IEEE P1363.
	518	*/
	519	int ec_GF2m_simple_dbl(const EC_GROUP group, EC_POINT r, const EC_POINT *a,
	520	BN_CTX *ctx)
	521	{
	522	return ec_GF2m_simple_add(group, r, a, a, ctx);
	523	}
7793f30e BM	524
7793f30e BM	525	int ec_GF2m_simple_invert(const EC_GROUP group, EC_POINT point, BN_CTX *ctx)
0f113f3e MC	526	{
	527	if (EC_POINT_is_at_infinity(group, point) \|\| BN_is_zero(point->Y))
	528	/* point is its own inverse */
	529	return 1;
7793f30e	530
0f113f3e MC	531	if (!EC_POINT_make_affine(group, point, ctx))
	532	return 0;
	533	return BN_GF2m_add(point->Y, point->X, point->Y);
	534	}
7793f30e BM	535
7793f30e BM	536	/* Indicates whether the given point is the point at infinity. */
0f113f3e MC	537	int ec_GF2m_simple_is_at_infinity(const EC_GROUP *group,
	538	const EC_POINT *point)
	539	{
	540	return BN_is_zero(point->Z);
	541	}
7793f30e	542
23a22b4c MC	543	/*-
23a22b4c MC	544	* Determines whether the given EC_POINT is an actual point on the curve defined
7793f30e BM	545	* in the EC_GROUP. A point is valid if it satisfies the Weierstrass equation:
	546	* y^2 + xy = x^3 + ax^2 + b.
	547	*/
0f113f3e MC	548	int ec_GF2m_simple_is_on_curve(const EC_GROUP group, const EC_POINT point,
	549	BN_CTX *ctx)
	550	{
	551	int ret = -1;
	552	BN_CTX *new_ctx = NULL;
	553	BIGNUM lh, y2;
	554	int (field_mul) (const EC_GROUP , BIGNUM , const BIGNUM ,
	555	const BIGNUM , BN_CTX );
	556	int (field_sqr) (const EC_GROUP , BIGNUM , const BIGNUM , BN_CTX *);
	557
	558	if (EC_POINT_is_at_infinity(group, point))
	559	return 1;
	560
	561	field_mul = group->meth->field_mul;
	562	field_sqr = group->meth->field_sqr;
	563
	564	/* only support affine coordinates */
	565	if (!point->Z_is_one)
	566	return -1;
	567
	568	if (ctx == NULL) {
	569	ctx = new_ctx = BN_CTX_new();
	570	if (ctx == NULL)
	571	return -1;
	572	}
	573
	574	BN_CTX_start(ctx);
	575	y2 = BN_CTX_get(ctx);
	576	lh = BN_CTX_get(ctx);
	577	if (lh == NULL)
	578	goto err;
	579
50e735f9 MC	580	/*-
	581	* We have a curve defined by a Weierstrass equation
	582	* y^2 + xy = x^3 + ax^2 + b.
	583	* <=> x^3 + ax^2 + xy + b + y^2 = 0
	584	* <=> ((x + a) * x + y ) * x + b + y^2 = 0
	585	*/
0f113f3e MC	586	if (!BN_GF2m_add(lh, point->X, group->a))
	587	goto err;
	588	if (!field_mul(group, lh, lh, point->X, ctx))
	589	goto err;
	590	if (!BN_GF2m_add(lh, lh, point->Y))
	591	goto err;
	592	if (!field_mul(group, lh, lh, point->X, ctx))
	593	goto err;
	594	if (!BN_GF2m_add(lh, lh, group->b))
	595	goto err;
	596	if (!field_sqr(group, y2, point->Y, ctx))
	597	goto err;
	598	if (!BN_GF2m_add(lh, lh, y2))
	599	goto err;
	600	ret = BN_is_zero(lh);
a0fda2cf	601
7793f30e	602	err:
a0fda2cf	603	BN_CTX_end(ctx);
23a1d5e9	604	BN_CTX_free(new_ctx);
0f113f3e MC	605	return ret;
0f113f3e MC	606	}
7793f30e	607
1d97c843 TH	608	/*-
1d97c843 TH	609	* Indicates whether two points are equal.
7793f30e BM	610	* Return values:
	611	* -1 error
	612	* 0 equal (in affine coordinates)
	613	* 1 not equal
	614	*/
0f113f3e MC	615	int ec_GF2m_simple_cmp(const EC_GROUP group, const EC_POINT a,
	616	const EC_POINT b, BN_CTX ctx)
	617	{
	618	BIGNUM aX, aY, bX, bY;
	619	BN_CTX *new_ctx = NULL;
	620	int ret = -1;
	621
	622	if (EC_POINT_is_at_infinity(group, a)) {
	623	return EC_POINT_is_at_infinity(group, b) ? 0 : 1;
	624	}
	625
	626	if (EC_POINT_is_at_infinity(group, b))
	627	return 1;
	628
	629	if (a->Z_is_one && b->Z_is_one) {
	630	return ((BN_cmp(a->X, b->X) == 0) && BN_cmp(a->Y, b->Y) == 0) ? 0 : 1;
	631	}
	632
	633	if (ctx == NULL) {
	634	ctx = new_ctx = BN_CTX_new();
	635	if (ctx == NULL)
	636	return -1;
	637	}
	638
	639	BN_CTX_start(ctx);
	640	aX = BN_CTX_get(ctx);
	641	aY = BN_CTX_get(ctx);
	642	bX = BN_CTX_get(ctx);
	643	bY = BN_CTX_get(ctx);
	644	if (bY == NULL)
	645	goto err;
	646
	647	if (!EC_POINT_get_affine_coordinates_GF2m(group, a, aX, aY, ctx))
	648	goto err;
	649	if (!EC_POINT_get_affine_coordinates_GF2m(group, b, bX, bY, ctx))
	650	goto err;
	651	ret = ((BN_cmp(aX, bX) == 0) && BN_cmp(aY, bY) == 0) ? 0 : 1;
7793f30e	652
0f113f3e	653	err:
a0fda2cf	654	BN_CTX_end(ctx);
23a1d5e9	655	BN_CTX_free(new_ctx);
0f113f3e MC	656	return ret;
0f113f3e MC	657	}
7793f30e BM	658
7793f30e BM	659	/* Forces the given EC_POINT to internally use affine coordinates. */
0f113f3e MC	660	int ec_GF2m_simple_make_affine(const EC_GROUP group, EC_POINT point,
	661	BN_CTX *ctx)
	662	{
	663	BN_CTX *new_ctx = NULL;
	664	BIGNUM x, y;
	665	int ret = 0;
	666
	667	if (point->Z_is_one \|\| EC_POINT_is_at_infinity(group, point))
	668	return 1;
	669
	670	if (ctx == NULL) {
	671	ctx = new_ctx = BN_CTX_new();
	672	if (ctx == NULL)
	673	return 0;
	674	}
	675
	676	BN_CTX_start(ctx);
	677	x = BN_CTX_get(ctx);
	678	y = BN_CTX_get(ctx);
	679	if (y == NULL)
	680	goto err;
	681
	682	if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx))
	683	goto err;
	684	if (!BN_copy(point->X, x))
	685	goto err;
	686	if (!BN_copy(point->Y, y))
	687	goto err;
	688	if (!BN_one(point->Z))
	689	goto err;
dd67493c	690	point->Z_is_one = 1;
0f113f3e MC	691
	692	ret = 1;
	693
	694	err:
a0fda2cf	695	BN_CTX_end(ctx);
23a1d5e9	696	BN_CTX_free(new_ctx);
0f113f3e MC	697	return ret;
	698	}
	699
	700	/*
	701	* Forces each of the EC_POINTs in the given array to use affine coordinates.
	702	*/
	703	int ec_GF2m_simple_points_make_affine(const EC_GROUP *group, size_t num,
	704	EC_POINT points[], BN_CTX ctx)
	705	{
	706	size_t i;
7793f30e	707
0f113f3e MC	708	for (i = 0; i < num; i++) {
	709	if (!group->meth->make_affine(group, points[i], ctx))
	710	return 0;
	711	}
7793f30e	712
0f113f3e MC	713	return 1;
0f113f3e MC	714	}
7793f30e	715
0f113f3e MC	716	/* Wrapper to simple binary polynomial field multiplication implementation. */
	717	int ec_GF2m_simple_field_mul(const EC_GROUP group, BIGNUM r,
	718	const BIGNUM a, const BIGNUM b, BN_CTX *ctx)
	719	{
	720	return BN_GF2m_mod_mul_arr(r, a, b, group->poly, ctx);
	721	}
7793f30e BM	722
7793f30e BM	723	/* Wrapper to simple binary polynomial field squaring implementation. */
0f113f3e MC	724	int ec_GF2m_simple_field_sqr(const EC_GROUP group, BIGNUM r,
	725	const BIGNUM a, BN_CTX ctx)
	726	{
	727	return BN_GF2m_mod_sqr_arr(r, a, group->poly, ctx);
	728	}
7793f30e BM	729
7793f30e BM	730	/* Wrapper to simple binary polynomial field division implementation. */
0f113f3e MC	731	int ec_GF2m_simple_field_div(const EC_GROUP group, BIGNUM r,
	732	const BIGNUM a, const BIGNUM b, BN_CTX *ctx)
	733	{
	734	return BN_GF2m_mod_div(r, a, b, group->field, ctx);
	735	}
b3310161 DSH	736
b3310161 DSH	737	#endif