Generate the client id, which is a fixed string of length 8 concatenated with 12 random bytes : String « Date Type « Android

Generate the client id, which is a fixed string of length 8 concatenated with 12 random bytes


import java.nio.ByteBuffer;
import java.util.Random;

 * Java Bittorrent API as its name indicates is a JAVA API that implements the Bittorrent Protocol
 * This project contains two packages:
 * 1. jBittorrentAPI is the "client" part, i.e. it implements all classes needed to publish
 *    files, share them and download them.
 *    This package also contains example classes on how a developer could create new applications.
 * 2. trackerBT is the "tracker" part, i.e. it implements a all classes needed to run
 *    a Bittorrent tracker that coordinates peers exchanges. *
 * Copyright (C) 2007 Baptiste Dubuis, Artificial Intelligence Laboratory, EPFL
 * This file is part of
 * Java Bittorrent API is free software and a free user study set-up;
 * 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 2 of the License, or
 * (at your option) any later version.
 * Java Bittorrent API is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with Java Bittorrent API; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * @version 1.0
 * @author Baptiste Dubuis
 * To contact the author:
 * email:
 * More information about Java Bittorrent API:

//package atorrentapi;

class Main {
   * Generate the client id, which is a fixed string of length 8 concatenated
   * with 12 random bytes
   * @return byte[]
  public static byte[] generateID() {
    byte[] id = new byte[12];

    Random r = new Random(System.currentTimeMillis());
    return concat("-ANDRTR-".getBytes(), id);

   * Concatenate the 2 byte arrays
   * @param a
   *            byte[]
   * @param b
   *            byte[]
   * @return byte[]
  public static byte[] concat2(byte[] a, byte[] b) {
    ByteBuffer bb = ByteBuffer.allocate(a.length + b.length);
    return bb.array();

   * Concatenate the 2 byte arrays
   * @param b1
   *            byte[]
   * @param b2
   *            byte[]
   * @return byte[]
  public static byte[] concat(byte[] b1, byte[] b2) {
    // Log.v("AndroidTor","size of the new byte array is "+(b1.length +
    // b2.length));
    byte[] b3 = new byte[b1.length + b2.length];
    System.arraycopy(b1, 0, b3, 0, b1.length);
    System.arraycopy(b2, 0, b3, b1.length, b2.length);

    return b3;

   * Concatenate the byte array and the byte
   * @param b1
   *            byte[]
   * @param b2
   *            byte
   * @return byte[]

  public static byte[] concat(byte[] b1, byte b2) {
    byte[] b3 = new byte[b1.length + 1];
    byte[] temp = new byte[] { b2 };
    System.arraycopy(b1, 0, b3, 0, b1.length);
    System.arraycopy(temp, 0, b3, b1.length, 1);
    return b3;



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