libjava/classpath/gnu/javax/crypto/prng/PBKDF2.java

   1 /* PBKDF2.java --
   2    Copyright (C) 2003, 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.prng;
  40
  41 import gnu.java.security.prng.BasePRNG;
  42 import gnu.java.security.prng.LimitReachedException;
  43 import gnu.javax.crypto.mac.HMac;
  44 import gnu.javax.crypto.mac.IMac;
  45
  46 import java.io.UnsupportedEncodingException;
  47 import java.util.Arrays;
  48 import java.util.HashMap;
  49 import java.util.Map;
  50
  51 /**
  52  * <p>An implementation of the <i>key derivation function</i> KDF2 from PKCS #5:
  53  * Password-Based Cryptography (<b>PBE</b>). This KDF is essentially a way to
  54  * transform a password and a salt into a stream of random bytes, which may then
  55  * be used to initialize a cipher or a MAC.</p>
  56  *
  57  * <p>This version uses a MAC as its pseudo-random function, and the password is
  58  * used as the key.</p>
  59  *
  60  * <p>References:</p>
  61  * <ol>
  62  *    <li>B. Kaliski, <a href="http://www.ietf.org/rfc/rfc2898.txt">RFC 2898:
  63  *    Password-Based Cryptography Specification, Version 2.0</a></li>
  64  * </ol>
  65  *
  66  * @version $Revision: 1.1 $
  67  */
  68 public class PBKDF2 extends BasePRNG implements Cloneable
  69 {
  70
  71   // Contstants and variables
  72   // -------------------------------------------------------------------------
  73
  74   /**
  75    * The bytes fed into the MAC. This is initially the concatenation of the
  76    * salt and the block number.
  77    */
  78   private byte[] in;
  79
  80   /** The iteration count. */
  81   private int iterationCount;
  82
  83   /** The salt. */
  84   private byte[] salt;
  85
  86   /** The MAC (the pseudo-random function we use). */
  87   private IMac mac;
  88
  89   /** The number of hLen-sized blocks generated. */
  90   private long count;
  91
  92   // Constructor(s)
  93   // -------------------------------------------------------------------------
  94
  95   /**
  96    * <p>Creates a new PBKDF2 object. The argument is the MAC that will serve as
  97    * the pseudo-random function. The MAC does not need to be initialized.</p>
  98    *
  99    * @param mac The pseudo-random function.
 100    */
 101   public PBKDF2(IMac mac)
 102   {
 103     super("PBKDF2-" + mac.name());
 104     this.mac = mac;
 105     iterationCount = -1;
 106   }
 107
 108   // Class methods
 109   // -------------------------------------------------------------------------
 110
 111   // Instance methods
 112   // -------------------------------------------------------------------------
 113
 114   public void setup(Map attributes)
 115   {
 116     Map macAttrib = new HashMap();
 117     macAttrib.put(HMac.USE_WITH_PKCS5_V2, Boolean.TRUE);
 118
 119     byte[] s = (byte[]) attributes.get(IPBE.SALT);
 120     if (s == null)
 121       {
 122         if (salt == null)
 123           {
 124             throw new IllegalArgumentException("no salt specified");
 125           } // Otherwise re-use.
 126       }
 127     else
 128       {
 129         salt = s;
 130       }
 131
 132     char[] password = (char[]) attributes.get(IPBE.PASSWORD);
 133     if (password != null)
 134       {
 135         try
 136           {
 137             macAttrib.put(IMac.MAC_KEY_MATERIAL,
 138                           new String(password).getBytes("UTF-8"));
 139           }
 140         catch (UnsupportedEncodingException uee)
 141           {
 142             throw new Error(uee.getMessage());
 143           }
 144       }
 145     else if (!initialised)
 146       {
 147         throw new IllegalArgumentException("no password specified");
 148       } // otherwise re-use previous password.
 149
 150     try
 151       {
 152         mac.init(macAttrib);
 153       }
 154     catch (Exception x)
 155       {
 156         throw new IllegalArgumentException(x.getMessage());
 157       }
 158
 159     Integer ic = (Integer) attributes.get(IPBE.ITERATION_COUNT);
 160     if (ic != null)
 161       {
 162         iterationCount = ic.intValue();
 163       }
 164     if (iterationCount <= 0)
 165       {
 166         throw new IllegalArgumentException("bad iteration count");
 167       }
 168
 169     count = 0L;
 170     buffer = new byte[mac.macSize()];
 171     try
 172       {
 173         fillBlock();
 174         //      } catch (Exception x) {
 175       }
 176     catch (LimitReachedException x)
 177       {
 178         //         x.printStackTrace(System.err);
 179         throw new Error(x.getMessage());
 180       }
 181   }
 182
 183   public void fillBlock() throws LimitReachedException
 184   {
 185     if (++count > ((1L << 32) - 1))
 186       {
 187         throw new LimitReachedException();
 188       }
 189     //      for (int i = 0; i < buffer.length; i++) {
 190     //         buffer[i] = 0;
 191     //      }
 192     Arrays.fill(buffer, (byte) 0x00);
 193     int limit = salt.length;
 194     //      in = new byte[salt.length + 4];
 195     in = new byte[limit + 4];
 196     System.arraycopy(salt, 0, in, 0, salt.length);
 197     //      in[salt.length  ] = (byte)(count >>> 24);
 198     //      in[salt.length+1] = (byte)(count >>> 16);
 199     //      in[salt.length+2] = (byte)(count >>>  8);
 200     //      in[salt.length+3] = (byte) count;
 201     in[limit++] = (byte) (count >>> 24);
 202     in[limit++] = (byte) (count >>> 16);
 203     in[limit++] = (byte) (count >>> 8);
 204     in[limit] = (byte) count;
 205     for (int i = 0; i < iterationCount; i++)
 206       {
 207         mac.reset();
 208         mac.update(in, 0, in.length);
 209         in = mac.digest();
 210         for (int j = 0; j < buffer.length; j++)
 211           {
 212             buffer[j] ^= in[j];
 213           }
 214       }
 215   }
 216 }