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 public class ARCFourSpi extends CipherSpi
  69 {
  70
  71   // Constants and variables.
  72   // -----------------------------------------------------------------------
  73
  74   private IRandom keystream;
  75
  76   // Constructors.
  77   // -----------------------------------------------------------------------
  78
  79   public ARCFourSpi()
  80   {
  81     super();
  82     keystream = PRNGFactory.getInstance(Registry.ARCFOUR_PRNG);
  83   }
  84
  85   // Methods implementing CipherSpi.
  86   // -----------------------------------------------------------------------
  87
  88   protected int engineGetBlockSize()
  89   {
  90     return 0; // stream cipher.
  91   }
  92
  93   protected void engineSetMode(String s) throws NoSuchAlgorithmException
  94   {
  95     // ignored.
  96   }
  97
  98   protected void engineSetPadding(String s) throws NoSuchPaddingException
  99   {
 100     // ignored.
 101   }
 102
 103   protected byte[] engineGetIV()
 104   {
 105     return null;
 106   }
 107
 108   protected int engineGetOutputSize(int in)
 109   {
 110     return in;
 111   }
 112
 113   protected AlgorithmParameters engineGetParameters()
 114   {
 115     return null;
 116   }
 117
 118   protected void engineInit(int mode, Key key, SecureRandom r)
 119       throws InvalidKeyException
 120   {
 121     if (mode != Cipher.ENCRYPT_MODE && mode != Cipher.DECRYPT_MODE)
 122       {
 123         throw new IllegalArgumentException(
 124                                            "arcfour is for encryption or decryption only");
 125       }
 126     if (key == null || !key.getFormat().equalsIgnoreCase("RAW"))
 127       {
 128         throw new InvalidKeyException("key must be non-null raw bytes");
 129       }
 130     HashMap attrib = new HashMap();
 131     attrib.put(ARCFour.ARCFOUR_KEY_MATERIAL, key.getEncoded());
 132     keystream.init(attrib);
 133   }
 134
 135   protected void engineInit(int mode, Key key, AlgorithmParameterSpec p,
 136                             SecureRandom r) throws InvalidKeyException,
 137       InvalidAlgorithmParameterException
 138   {
 139     engineInit(mode, key, r);
 140   }
 141
 142   protected void engineInit(int mode, Key key, AlgorithmParameters p,
 143                             SecureRandom r) throws InvalidKeyException,
 144       InvalidAlgorithmParameterException
 145   {
 146     engineInit(mode, key, r);
 147   }
 148
 149   protected byte[] engineUpdate(byte[] in, int offset, int length)
 150   {
 151     if (length < 0 || offset < 0 || length + offset > in.length)
 152       {
 153         throw new ArrayIndexOutOfBoundsException();
 154       }
 155     byte[] result = new byte[length];
 156     try
 157       {
 158         for (int i = 0; i < length; i++)
 159           {
 160             result[i] = (byte) (in[i + offset] ^ keystream.nextByte());
 161           }
 162       }
 163     catch (LimitReachedException wontHappen)
 164       {
 165       }
 166     return result;
 167   }
 168
 169   protected int engineUpdate(byte[] in, int inOffset, int length, byte[] out,
 170                              int outOffset) throws ShortBufferException
 171   {
 172     if (length < 0 || inOffset < 0 || length + inOffset > in.length
 173         || outOffset < 0)
 174       {
 175         throw new ArrayIndexOutOfBoundsException();
 176       }
 177     if (outOffset + length > out.length)
 178       {
 179         throw new ShortBufferException();
 180       }
 181     try
 182       {
 183         for (int i = 0; i < length; i++)
 184           {
 185             out[i + outOffset] = (byte) (in[i + inOffset] ^ keystream.nextByte());
 186           }
 187       }
 188     catch (LimitReachedException wontHappen)
 189       {
 190       }
 191     return length;
 192   }
 193
 194   protected byte[] engineDoFinal(byte[] in, int offset, int length)
 195       throws IllegalBlockSizeException, BadPaddingException
 196   {
 197     return engineUpdate(in, offset, length);
 198   }
 199
 200   protected int engineDoFinal(byte[] in, int inOffset, int length, byte[] out,
 201                               int outOffset) throws ShortBufferException,
 202       IllegalBlockSizeException, BadPaddingException
 203   {
 204     return engineUpdate(in, inOffset, length, out, outOffset);
 205   }
 206 }