Android Open Source - pandoroid Blowfish

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License

The source code is released under:

GNU General Public License

Java Source Code

/* Pandoroid Radio - open source pandora.com client for android
 * Copyright (C) 2011  Andrew Regner <andrew@aregner.com>
 * //from   w ww .  j  a v a 2  s  .c  om
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/* 
 * This is a Java port of the "blowfish.py" module from the Pithos source code.
 * 
 * Pithos is released under the GNU GPL v3, Copyright (C) 2010 Kevin Mehall <km@kevinmehall.net>
 * blowfish.py is (C) 2002 Michael Gilfix <mgilfix@eecs.tufts.edu>
 */
package com.aregner.pandora;


public class Blowfish {
  
  // Cipher directions
  private static final int ENCRYPT = 0;
  private static final int DECRYPT = 1;
  
  // For the roundFunc()
  private static final long modulus = (long) Math.pow(2L, 32);
  
  private long[] p_boxes;
  private long[][] s_boxes;
  
  
  public Blowfish(long[] p_boxes, long[][] s_boxes) {
    this.p_boxes = p_boxes;
    this.s_boxes = s_boxes;
  }
  
  protected long[] cipher(long xl, long xr, int direction) {
    long temp_x;
    long[] result = {0L, 0L};
    
    if(direction == Blowfish.ENCRYPT) {
      for(int i=0; i<16; i++) {
        xl = xl ^ this.p_boxes[i];
        xr = this.roundFunc(xl) ^ xr;
        temp_x = xl; xl = xr; xr = temp_x;
      }
      temp_x = xl; xl = xr; xr = temp_x;
      xr = xr ^ this.p_boxes[16];
      xl = xl ^ this.p_boxes[17];
    }
    else if(direction == Blowfish.DECRYPT) {
      for(int i=17; i>1; i--) {
        xl = xl ^ this.p_boxes[i];
        xr = this.roundFunc(xl) ^ xr;
        temp_x = xl; xl = xr; xr = temp_x;
      }
      temp_x = xl; xl = xr; xr = temp_x;
      xr = xr ^ this.p_boxes[1];
      xl = xl ^ this.p_boxes[0];
    }
    
    result[0] = xl;
    result[1] = xr;
    return result;
  }
  
  private long roundFunc(long xl) {
    long a = (xl & 0xff000000) >> 24;
    long b = (xl & 0x00ff0000) >> 16;
    long c = (xl & 0x0000ff00) >> 8;
    long d = xl & 0x000000ff;
    
    // Perform all ops as longs then and out the last 32-bits to obtain the integer
    long f = ((long)this.s_boxes[0][(int)a] + (long)this.s_boxes[1][(int)b]) % Blowfish.modulus;
    f = f ^ (long)this.s_boxes[2][(int)c];
    f = f + (long)this.s_boxes[3][(int)d];
    f = (f % Blowfish.modulus) & 0xffffffff;
    
    return f;
  }
  
  public long[] encrypt(char[] data) {
    long[] chars = new long[8];
    
    if(data.length != 8) {
      throw new RuntimeException("Attempted to encrypt data of invalid block length: "+data.length);
    }
    
    // Use big endianess since that's what everyone else uses
    long xl = (long)data[3] | ((long)data[2] << 8) | ((long)data[1] << 16) | ((long)data[0] << 24);
    long xr = (long)data[7] | ((long)data[6] << 8) | ((long)data[5] << 16) | ((long)data[4] << 24);
    
    long[] temp_x = this.cipher(xl, xr, Blowfish.ENCRYPT);
    long cl = temp_x[0];
    long cr = temp_x[1];

    chars[0] = ((cl >> 24) & 0xff);
    chars[1] = ((cl >> 16) & 0xff);
    chars[2] = ((cl >> 8) & 0xff);
    chars[3] = (cl & 0xff);
    chars[4] = ((cr >> 24) & 0xff);
    chars[5] = ((cr >> 16) & 0xff);
    chars[6] = ((cr >> 8) & 0xff);
    chars[7] = (cr & 0xff);
    
    return chars;
  }
  
  public String decrypt(char[] data) {
    long[] chars = new long[8];
    StringBuilder result = new StringBuilder(8);
    
    if(data.length != 8) {
      throw new RuntimeException("Attempted to encrypt data of invalid block length: "+data.length);
    }
    
    // Use big endianess since that's what everyone else uses
    long cl = (long)data[3] | ((long)data[2] << 8) | ((long)data[1] << 16) | ((long)data[0] << 24);
    long cr = (long)data[7] | ((long)data[6] << 8) | ((long)data[5] << 16) | ((long)data[4] << 24);
    
    long[] temp_x = this.cipher(cl, cr, Blowfish.DECRYPT);
    long xl = temp_x[0];
    long xr = temp_x[1];

    chars[0] = ((xl >> 24) & 0xff);
    chars[1] = ((xl >> 16) & 0xff);
    chars[2] = ((xl >> 8) & 0xff);
    chars[3] = (xl & 0xff);
    chars[4] = ((xr >> 24) & 0xff);
    chars[5] = ((xr >> 16) & 0xff);
    chars[6] = ((xr >> 8) & 0xff);
    chars[7] = (xr & 0xff);
    
    for(int c=0; c<chars.length; c++) {
      result.append(String.valueOf((char)chars[c]));
    }
    
    return result.toString();
  }
  
  public int blocksize() {
    return 8;
  }
  
  public int keyLength() {
    return 56;
  }
  
  public int keyBits() {
    return 56 * 8;
  }
  
  public static void main(String[] args) {
    
  }
  
}

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