/*
 * Copyright (c) [2016] [ <ether.camp> ]
 * This file is part of the ethereumJ library.
 *
 * The ethereumJ library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * The ethereumJ library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the ethereumJ library. If not, see <http://www.gnu.org/licenses/>.
 */
package org.ethereum.crypto.zksnark;

import java.math.BigInteger;

/**
 * Common params for BN curves, its derivatives and pairing
 *
 * @author Mikhail Kalinin
 * @since 31.08.2017
 */
class Params {

    /**
     * "p" field parameter of F_p, F_p2, F_p6 and F_p12
     */
    static final BigInteger P = new BigInteger("21888242871839275222246405745257275088696311157297823662689037894645226208583");

    /**
     * "r" order of {@link BN128G2} cyclic subgroup
     */
    static final BigInteger R = new BigInteger("21888242871839275222246405745257275088548364400416034343698204186575808495617");

    /**
     * "b" curve parameter for {@link BN128Fp}
     */
    static final Fp B_Fp = Fp.create(BigInteger.valueOf(3));

    /**
     * Twist parameter for the curves
     */
    static final Fp2 TWIST = Fp2.create(BigInteger.valueOf(9), BigInteger.valueOf(1));

    /**
     * "b" curve parameter for {@link BN128Fp2}
     */
    static final Fp2 B_Fp2 = B_Fp.mul(TWIST.inverse());

    static final Fp2 TWIST_MUL_BY_P_X = Fp2.create(
            new BigInteger("21575463638280843010398324269430826099269044274347216827212613867836435027261"),
            new BigInteger("10307601595873709700152284273816112264069230130616436755625194854815875713954")
    );

    static final Fp2 TWIST_MUL_BY_P_Y = Fp2.create(
            new BigInteger("2821565182194536844548159561693502659359617185244120367078079554186484126554"),
            new BigInteger("3505843767911556378687030309984248845540243509899259641013678093033130930403")
    );

    static final BigInteger PAIRING_FINAL_EXPONENT_Z = new BigInteger("4965661367192848881");
}
