Source for gnu.javax.crypto.jce.cipher.ARCFourSpi

   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 stream
  66:  * cipher.
  67:  */
  68: public class ARCFourSpi
  69:     extends CipherSpi
  70: {
  71:   private IRandom keystream;
  72: 
  73:   public ARCFourSpi()
  74:   {
  75:     super();
  76:     keystream = PRNGFactory.getInstance(Registry.ARCFOUR_PRNG);
  77:   }
  78: 
  79:   protected int engineGetBlockSize()
  80:   {
  81:     return 0; // stream cipher.
  82:   }
  83: 
  84:   protected void engineSetMode(String s) throws NoSuchAlgorithmException
  85:   {
  86:     // ignored.
  87:   }
  88: 
  89:   protected void engineSetPadding(String s) throws NoSuchPaddingException
  90:   {
  91:     // ignored.
  92:   }
  93: 
  94:   protected byte[] engineGetIV()
  95:   {
  96:     return null;
  97:   }
  98: 
  99:   protected int engineGetOutputSize(int in)
 100:   {
 101:     return in;
 102:   }
 103: 
 104:   protected AlgorithmParameters engineGetParameters()
 105:   {
 106:     return null;
 107:   }
 108: 
 109:   protected void engineInit(int mode, Key key, SecureRandom r)
 110:       throws InvalidKeyException
 111:   {
 112:     if (mode != Cipher.ENCRYPT_MODE && mode != Cipher.DECRYPT_MODE)
 113:       throw new IllegalArgumentException(
 114:           "arcfour is for encryption or decryption only");
 115:     if (key == null || ! key.getFormat().equalsIgnoreCase("RAW"))
 116:       throw new InvalidKeyException("key must be non-null raw bytes");
 117:     HashMap attrib = new HashMap();
 118:     attrib.put(ARCFour.ARCFOUR_KEY_MATERIAL, key.getEncoded());
 119:     keystream.init(attrib);
 120:   }
 121: 
 122:   protected void engineInit(int mode, Key key, AlgorithmParameterSpec p,
 123:                             SecureRandom r) throws InvalidKeyException,
 124:       InvalidAlgorithmParameterException
 125:   {
 126:     engineInit(mode, key, r);
 127:   }
 128: 
 129:   protected void engineInit(int mode, Key key, AlgorithmParameters p,
 130:                             SecureRandom r) throws InvalidKeyException,
 131:       InvalidAlgorithmParameterException
 132:   {
 133:     engineInit(mode, key, r);
 134:   }
 135: 
 136:   protected byte[] engineUpdate(byte[] in, int offset, int length)
 137:   {
 138:     if (length < 0 || offset < 0 || length + offset > in.length)
 139:       throw new ArrayIndexOutOfBoundsException();
 140:     byte[] result = new byte[length];
 141:     try
 142:       {
 143:         for (int i = 0; i < length; i++)
 144:           result[i] = (byte)(in[i + offset] ^ keystream.nextByte());
 145:       }
 146:     catch (LimitReachedException wontHappen)
 147:       {
 148:       }
 149:     return result;
 150:   }
 151: 
 152:   protected int engineUpdate(byte[] in, int inOffset, int length, byte[] out,
 153:                              int outOffset) throws ShortBufferException
 154:   {
 155:     if (length < 0 || inOffset < 0 || length + inOffset > in.length
 156:         || outOffset < 0)
 157:       throw new ArrayIndexOutOfBoundsException();
 158:     if (outOffset + length > out.length)
 159:       throw new ShortBufferException();
 160:     try
 161:       {
 162:         for (int i = 0; i < length; i++)
 163:           out[i + outOffset] = (byte)(in[i + inOffset] ^ keystream.nextByte());
 164:       }
 165:     catch (LimitReachedException wontHappen)
 166:       {
 167:       }
 168:     return length;
 169:   }
 170: 
 171:   protected byte[] engineDoFinal(byte[] in, int offset, int length)
 172:       throws IllegalBlockSizeException, BadPaddingException
 173:   {
 174:     return engineUpdate(in, offset, length);
 175:   }
 176: 
 177:   protected int engineDoFinal(byte[] in, int inOffset, int length, byte[] out,
 178:                               int outOffset) throws ShortBufferException,
 179:       IllegalBlockSizeException, BadPaddingException
 180:   {
 181:     return engineUpdate(in, inOffset, length, out, outOffset);
 182:   }
 183: }