com.l2jserver.service.network.keygen.SecureBlowfishKeygenService.java Source code

Introduction

Here is the source code for com.l2jserver.service.network.keygen.SecureBlowfishKeygenService.java

Source

/*
 * This file is part of l2jserver2 <l2jserver2.com>.
 *
 * l2jserver2 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.
 *
 * l2jserver2 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 l2jserver2.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.l2jserver.service.network.keygen;

import org.apache.commons.math.random.RandomData;
import org.apache.commons.math.random.RandomDataImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;
import com.l2jserver.service.AbstractService;
import com.l2jserver.service.ServiceStartException;
import com.l2jserver.service.ServiceStopException;

/**
 * This implementation of {@link BlowfishKeygenService} generates
 * cryptographically safe keys but at the cost of speed. The key generation is
 * much slower than on a pseudo-random generator.
 * 
 * @author <a href="http://www.rogiel.com">Rogiel</a>
 */
public class SecureBlowfishKeygenService extends AbstractService implements BlowfishKeygenService {
    /**
     * The logger
     */
    private final Logger log = LoggerFactory.getLogger(this.getClass());

    /**
     * The random number generator
     */
    private RandomData random;

    @Override
    protected void doStart() throws ServiceStartException {
        random = new RandomDataImpl();
    }

    @Override
    public byte[] generate(int strength) {
        Preconditions.checkArgument(strength % 8 == 0, "strength must be a multiple of 8");
        log.debug("Generating a new {}-bit key", strength);

        final byte[] key = new byte[strength / 8];
        // randomize the 8 first bytes
        for (int i = 0; i < key.length; i++) {
            key[i] = (byte) random.nextSecureInt(0, 255);
        }

        // the last 8 bytes are static and are assumed by the client, they are
        // never sent in the SM_KEY packet
        key[8] = (byte) 0xc8;
        key[9] = (byte) 0x27;
        key[10] = (byte) 0x93;
        key[11] = (byte) 0x01;
        key[12] = (byte) 0xa1;
        key[13] = (byte) 0x6c;
        key[14] = (byte) 0x31;
        key[15] = (byte) 0x97;
        return key;
    }

    @Override
    protected void doStop() throws ServiceStopException {
        random = null;
    }
}