path: root/crypto/ec/ecp_mont.c

/* crypto/ec/ecp_mont.c */
/*
 * Originally written by Bodo Moeller for the OpenSSL project.
 */
/* ====================================================================
 * Copyright (c) 1998-2001 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 "ec_lcl.h"

const EC_METHOD *EC_GFp_mont_method(void)
{
    static const EC_METHOD ret = {
        EC_FLAGS_DEFAULT_OCT,
        NID_X9_62_prime_field,
        ec_GFp_mont_group_init,
        ec_GFp_mont_group_finish,
        ec_GFp_mont_group_clear_finish,
        ec_GFp_mont_group_copy,
        ec_GFp_mont_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,
        0, 0, 0,
        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_mont_field_mul,
        ec_GFp_mont_field_sqr,
        0 /* field_div */ ,
        ec_GFp_mont_field_encode,
        ec_GFp_mont_field_decode,
        ec_GFp_mont_field_set_to_one
    };

    return &ret;
}

int ec_GFp_mont_group_init(EC_GROUP *group)
{
    int ok;

    ok = ec_GFp_simple_group_init(group);
    group->field_data1 = NULL;
    group->field_data2 = NULL;
    return ok;
}

void ec_GFp_mont_group_finish(EC_GROUP *group)
{
    if (group->field_data1 != NULL) {
        BN_MONT_CTX_free(group->field_data1);
        group->field_data1 = NULL;
    }
    if (group->field_data2 != NULL) {
        BN_free(group->field_data2);
        group->field_data2 = NULL;
    }
    ec_GFp_simple_group_finish(group);
}

void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
{
    if (group->field_data1 != NULL) {
        BN_MONT_CTX_free(group->field_data1);
        group->field_data1 = NULL;
    }
    if (group->field_data2 != NULL) {
        BN_clear_free(group->field_data2);
        group->field_data2 = NULL;
    }
    ec_GFp_simple_group_clear_finish(group);
}

int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
{
    if (dest->field_data1 != NULL) {
        BN_MONT_CTX_free(dest->field_data1);
        dest->field_data1 = NULL;
    }
    if (dest->field_data2 != NULL) {
        BN_clear_free(dest->field_data2);
        dest->field_data2 = NULL;
    }

    if (!ec_GFp_simple_group_copy(dest, src))
        return 0;

    if (src->field_data1 != NULL) {
        dest->field_data1 = BN_MONT_CTX_new();
        if (dest->field_data1 == NULL)
            return 0;
        if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
            goto err;
    }
    if (src->field_data2 != NULL) {
        dest->field_data2 = BN_dup(src->field_data2);
        if (dest->field_data2 == NULL)
            goto err;
    }

    return 1;

 err:
    if (dest->field_data1 != NULL) {
        BN_MONT_CTX_free(dest->field_data1);
        dest->field_data1 = NULL;
    }
    return 0;
}

int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
                                const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
{
    BN_CTX *new_ctx = NULL;
    BN_MONT_CTX *mont = NULL;
    BIGNUM *one = NULL;
    int ret = 0;

    if (group->field_data1 != NULL) {
        BN_MONT_CTX_free(group->field_data1);
        group->field_data1 = NULL;
    }
    if (group->field_data2 != NULL) {
        BN_free(group->field_data2);
        group->field_data2 = NULL;
    }

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        if (ctx == NULL)
            return 0;
    }

    mont = BN_MONT_CTX_new();
    if (mont == NULL)
        goto err;
    if (!BN_MONT_CTX_set(mont, p, ctx)) {
        ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
        goto err;
    }
    one = BN_new();
    if (one == NULL)
        goto err;
    if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
        goto err;

    group->field_data1 = mont;
    mont = NULL;
    group->field_data2 = one;
    one = NULL;

    ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);

    if (!ret) {
        BN_MONT_CTX_free(group->field_data1);
        group->field_data1 = NULL;
        BN_free(group->field_data2);
        group->field_data2 = NULL;
    }

 err:
    if (new_ctx != NULL)
        BN_CTX_free(new_ctx);
    if (mont != NULL)
        BN_MONT_CTX_free(mont);
    return ret;
}

int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
                          const BIGNUM *b, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
}

int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
                          BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
}

int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
                             const BIGNUM *a, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
}

int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r,
                             const BIGNUM *a, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_from_montgomery(r, a, group->field_data1, ctx);
}

int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r,
                                 BN_CTX *ctx)
{
    if (group->field_data2 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    if (!BN_copy(r, group->field_data2))
        return 0;
    return 1;
}