libjava/classpath/gnu/javax/crypto/jce/cipher/ARCFourSpi.java

   1 /* ARCFourSpi.java --
   2    Copyright (C) 2002, 2006  Free Software Foundation, Inc.
   3
   4 This file is a part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or (at
   9 your option) any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19 USA
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version.  */
  37
  38
  39 package gnu.javax.crypto.jce.cipher;
  40
  41 import gnu.java.security.Registry;
  42 import gnu.javax.crypto.prng.ARCFour;
  43 import gnu.java.security.prng.IRandom;
  44 import gnu.java.security.prng.LimitReachedException;
  45 import gnu.javax.crypto.prng.PRNGFactory;
  46
  47 import java.security.AlgorithmParameters;
  48 import java.security.InvalidAlgorithmParameterException;
  49 import java.security.InvalidKeyException;
  50 import java.security.Key;
  51 import java.security.NoSuchAlgorithmException;
  52 import java.security.SecureRandom;
  53 import java.security.spec.AlgorithmParameterSpec;
  54
  55 import java.util.HashMap;
  56
  57 import javax.crypto.BadPaddingException;
  58 import javax.crypto.Cipher;
  59 import javax.crypto.CipherSpi;
  60 import javax.crypto.IllegalBlockSizeException;
  61 import javax.crypto.NoSuchPaddingException;
  62 import javax.crypto.ShortBufferException;
  63
  64 /**
  65  * The <i>Service Provider Interface</i> (<b>SPI</b>) for the ARCFOUR
  66  * stream cipher.
  67  *
  68  * @version $Revision: 1.1 $
  69  */
  70 public class ARCFourSpi extends CipherSpi
  71 {
  72
  73   // Constants and variables.
  74   // -----------------------------------------------------------------------
  75
  76   private IRandom keystream;
  77
  78   // Constructors.
  79   // -----------------------------------------------------------------------
  80
  81   public ARCFourSpi()
  82   {
  83     super();
  84     keystream = PRNGFactory.getInstance(Registry.ARCFOUR_PRNG);
  85   }
  86
  87   // Methods implementing CipherSpi.
  88   // -----------------------------------------------------------------------
  89
  90   protected int engineGetBlockSize()
  91   {
  92     return 0; // stream cipher.
  93   }
  94
  95   protected void engineSetMode(String s) throws NoSuchAlgorithmException
  96   {
  97     // ignored.
  98   }
  99
 100   protected void engineSetPadding(String s) throws NoSuchPaddingException
 101   {
 102     // ignored.
 103   }
 104
 105   protected byte[] engineGetIV()
 106   {
 107     return null;
 108   }
 109
 110   protected int engineGetOutputSize(int in)
 111   {
 112     return in;
 113   }
 114
 115   protected AlgorithmParameters engineGetParameters()
 116   {
 117     return null;
 118   }
 119
 120   protected void engineInit(int mode, Key key, SecureRandom r)
 121       throws InvalidKeyException
 122   {
 123     if (mode != Cipher.ENCRYPT_MODE && mode != Cipher.DECRYPT_MODE)
 124       {
 125         throw new IllegalArgumentException(
 126                                            "arcfour is for encryption or decryption only");
 127       }
 128     if (key == null || !key.getFormat().equalsIgnoreCase("RAW"))
 129       {
 130         throw new InvalidKeyException("key must be non-null raw bytes");
 131       }
 132     HashMap attrib = new HashMap();
 133     attrib.put(ARCFour.ARCFOUR_KEY_MATERIAL, key.getEncoded());
 134     keystream.init(attrib);
 135   }
 136
 137   protected void engineInit(int mode, Key key, AlgorithmParameterSpec p,
 138                             SecureRandom r) throws InvalidKeyException,
 139       InvalidAlgorithmParameterException
 140   {
 141     engineInit(mode, key, r);
 142   }
 143
 144   protected void engineInit(int mode, Key key, AlgorithmParameters p,
 145                             SecureRandom r) throws InvalidKeyException,
 146       InvalidAlgorithmParameterException
 147   {
 148     engineInit(mode, key, r);
 149   }
 150
 151   protected byte[] engineUpdate(byte[] in, int offset, int length)
 152   {
 153     if (length < 0 || offset < 0 || length + offset > in.length)
 154       {
 155         throw new ArrayIndexOutOfBoundsException();
 156       }
 157     byte[] result = new byte[length];
 158     try
 159       {
 160         for (int i = 0; i < length; i++)
 161           {
 162             result[i] = (byte) (in[i + offset] ^ keystream.nextByte());
 163           }
 164       }
 165     catch (LimitReachedException wontHappen)
 166       {
 167       }
 168     return result;
 169   }
 170
 171   protected int engineUpdate(byte[] in, int inOffset, int length, byte[] out,
 172                              int outOffset) throws ShortBufferException
 173   {
 174     if (length < 0 || inOffset < 0 || length + inOffset > in.length
 175         || outOffset < 0)
 176       {
 177         throw new ArrayIndexOutOfBoundsException();
 178       }
 179     if (outOffset + length > out.length)
 180       {
 181         throw new ShortBufferException();
 182       }
 183     try
 184       {
 185         for (int i = 0; i < length; i++)
 186           {
 187             out[i + outOffset] = (byte) (in[i + inOffset] ^ keystream.nextByte());
 188           }
 189       }
 190     catch (LimitReachedException wontHappen)
 191       {
 192       }
 193     return length;
 194   }
 195
 196   protected byte[] engineDoFinal(byte[] in, int offset, int length)
 197       throws IllegalBlockSizeException, BadPaddingException
 198   {
 199     return engineUpdate(in, offset, length);
 200   }
 201
 202   protected int engineDoFinal(byte[] in, int inOffset, int length, byte[] out,
 203                               int outOffset) throws ShortBufferException,
 204       IllegalBlockSizeException, BadPaddingException
 205   {
 206     return engineUpdate(in, inOffset, length, out, outOffset);
 207   }
 208 }