libjava/classpath/gnu/javax/crypto/jce/mac/MacAdapter.java

   1 /* MacAdapter.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.mac;
  40
  41 import gnu.javax.crypto.mac.IMac;
  42 import gnu.javax.crypto.mac.MacFactory;
  43
  44 import java.security.InvalidAlgorithmParameterException;
  45 import java.security.InvalidKeyException;
  46 import java.security.Key;
  47 import java.security.spec.AlgorithmParameterSpec;
  48 import java.util.HashMap;
  49 import java.util.Map;
  50 import javax.crypto.MacSpi;
  51
  52 /**
  53  * The implementation of a generic {@link javax.crypto.Mac} adapter class to
  54  * wrap GNU MAC instances.
  55  * <p>
  56  * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) for
  57  * the {@link javax.crypto.Mac} class, which provides the functionality of a
  58  * message authentication code algorithm, such as the <i>Hashed Message
  59  * Authentication Code</i> (<b>HMAC</b>) algorithms.
  60  */
  61 class MacAdapter
  62     extends MacSpi
  63     implements Cloneable
  64 {
  65   /** Our MAC instance. */
  66   protected IMac mac;
  67   /** Our MAC attributes. */
  68   protected Map attributes;
  69
  70   /**
  71    * Creates a new Mac instance for the given name.
  72    *
  73    * @param name The name of the mac to create.
  74    */
  75   protected MacAdapter(String name)
  76   {
  77     mac = MacFactory.getInstance(name);
  78     attributes = new HashMap();
  79   }
  80
  81   /**
  82    * Private constructor for cloning purposes.
  83    *
  84    * @param mac a clone of the internal {@link IMac} instance.
  85    * @param attributes a clone of the current {@link Map} of attributes.
  86    */
  87   private MacAdapter(IMac mac, Map attributes)
  88   {
  89     super();
  90
  91     this.mac = mac;
  92     this.attributes = attributes;
  93   }
  94
  95   public Object clone() throws CloneNotSupportedException
  96   {
  97     return new MacAdapter((IMac) mac.clone(), new HashMap(attributes));
  98   }
  99
 100   protected byte[] engineDoFinal()
 101   {
 102     byte[] result = mac.digest();
 103     engineReset();
 104     return result;
 105   }
 106
 107   protected int engineGetMacLength()
 108   {
 109     return mac.macSize();
 110   }
 111
 112   protected void engineInit(Key key, AlgorithmParameterSpec params)
 113       throws InvalidKeyException, InvalidAlgorithmParameterException
 114   {
 115     if (! key.getFormat().equalsIgnoreCase("RAW"))
 116       throw new InvalidKeyException("unknown key format " + key.getFormat());
 117     attributes.put(IMac.MAC_KEY_MATERIAL, key.getEncoded());
 118     mac.reset();
 119     mac.init(attributes);
 120   }
 121
 122   protected void engineReset()
 123   {
 124     mac.reset();
 125   }
 126
 127   protected void engineUpdate(byte b)
 128   {
 129     mac.update(b);
 130   }
 131
 132   protected void engineUpdate(byte[] in, int off, int len)
 133   {
 134     mac.update(in, off, len);
 135   }
 136 }