/*

 * Copyright 2001-2018 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 <limits.h>

#include <openssl/err.h>

#include <openssl/obj_mac.h>

#include "ec_lcl.h"

const EC_METHOD *EC_GFp_nist_method(void)

{

    static const EC_METHOD ret = {

        EC_FLAGS_DEFAULT_OCT,

        NID_X9_62_prime_field,

        ec_GFp_simple_group_init,

        ec_GFp_simple_group_finish,

        ec_GFp_simple_group_clear_finish,

        ec_GFp_nist_group_copy,

        ec_GFp_nist_group_set_curve,

        ec_GFp_simple_group_get_curve,

        ec_GFp_simple_group_get_degree,

        ec_group_simple_order_bits,

        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_nist_field_mul,

        ec_GFp_nist_field_sqr,

        0 /* 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,

        0, /* field_inverse_mod_ord */

        ec_GFp_simple_blind_coordinates,

        ec_GFp_simple_ladder_pre,

        ec_GFp_simple_ladder_step,

        ec_GFp_simple_ladder_post

    };

    return &ret;

}

int ec_GFp_nist_group_copy(EC_GROUP *dest, const EC_GROUP *src)

{

    dest->field_mod_func = src->field_mod_func;

    return ec_GFp_simple_group_copy(dest, src);

}

int ec_GFp_nist_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;

    if (ctx == NULL)

        if ((ctx = new_ctx = BN_CTX_new()) == NULL)

            return 0;

    BN_CTX_start(ctx);

    if (BN_ucmp(BN_get0_nist_prime_192(), p) == 0)

        group->field_mod_func = BN_nist_mod_192;

    else if (BN_ucmp(BN_get0_nist_prime_224(), p) == 0)

        group->field_mod_func = BN_nist_mod_224;

    else if (BN_ucmp(BN_get0_nist_prime_256(), p) == 0)

        group->field_mod_func = BN_nist_mod_256;

    else if (BN_ucmp(BN_get0_nist_prime_384(), p) == 0)

        group->field_mod_func = BN_nist_mod_384;

    else if (BN_ucmp(BN_get0_nist_prime_521(), p) == 0)

        group->field_mod_func = BN_nist_mod_521;

    else {

        ECerr(EC_F_EC_GFP_NIST_GROUP_SET_CURVE, EC_R_NOT_A_NIST_PRIME);

        goto err;

    }

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

 err:

    BN_CTX_end(ctx);

    BN_CTX_free(new_ctx);

    return ret;

}

int ec_GFp_nist_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

                          const BIGNUM *b, BN_CTX *ctx)

{

    int ret = 0;

    BN_CTX *ctx_new = NULL;

    if (!group || !r || !a || !b) {

        ECerr(EC_F_EC_GFP_NIST_FIELD_MUL, ERR_R_PASSED_NULL_PARAMETER);

        goto err;

    }

    if (!ctx)

        if ((ctx_new = ctx = BN_CTX_new()) == NULL)

            goto err;

    if (!BN_mul(r, a, b, ctx))

        goto err;

    if (!group->field_mod_func(r, r, group->field, ctx))

        goto err;

    ret = 1;

 err:

    BN_CTX_free(ctx_new);

    return ret;

}

int ec_GFp_nist_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,

                          BN_CTX *ctx)

{

    int ret = 0;

    BN_CTX *ctx_new = NULL;

    if (!group || !r || !a) {

        ECerr(EC_F_EC_GFP_NIST_FIELD_SQR, EC_R_PASSED_NULL_PARAMETER);

        goto err;

    }

    if (!ctx)

        if ((ctx_new = ctx = BN_CTX_new()) == NULL)

            goto err;

    if (!BN_sqr(r, a, ctx))

        goto err;

    if (!group->field_mod_func(r, r, group->field, ctx))

        goto err;

    ret = 1;

 err:

    BN_CTX_free(ctx_new);

    return ret;

}