Validator.java

/*
 * Copyright (C) 2020-2024 by Savoir-faire Linux
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package net.jami.jams.common.utils;

import net.jami.jams.common.objects.requests.CreateCARequest;

import java.math.BigInteger;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;

public class Validator {

    public static boolean validateCARequests(CreateCARequest request) {
        if (request.getCertificate() == null || request.getPrivateKey() == null) {
            return true;
        }

        if (request.getCertificate().getBasicConstraints() == -1) {
            return false;
        }

        RSAPublicKey rsaPublicKey = (RSAPublicKey) request.getCertificate().getPublicKey();
        RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) request.getPrivateKey();

        return rsaPublicKey.getModulus().equals(rsaPrivateKey.getModulus())
                // https://en.wikipedia.org/wiki/RSA_(cryptosystem)
                // 2 ** (e * d - 1) mod n == 1
                && BigInteger.valueOf(2)
                        .modPow(
                                rsaPublicKey
                                        .getPublicExponent()
                                        .multiply(rsaPrivateKey.getPrivateExponent())
                                        .subtract(BigInteger.ONE),
                                rsaPublicKey.getModulus())
                        .equals(BigInteger.ONE);
    }
}