001    /* RC5ParameterSpec.java -- parameters for RC5.
002       Copyright (C) 2004  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.crypto.spec;
040    
041    import java.security.spec.AlgorithmParameterSpec;
042    
043    /**
044     * A wrapper for parameters to the <a
045     * href="http://www.rsasecurity.com/rsalabs/faq/3-6-4.html">RC5</a>
046     * block cipher.
047     *
048     * @author Casey Marshall (csm@gnu.org)
049     * @since 1.4
050     */
051    public class RC5ParameterSpec implements AlgorithmParameterSpec
052    {
053    
054      // Fields.
055      // ------------------------------------------------------------------------
056    
057      /** The IV. */
058      private byte[] iv;
059    
060      /** The number of rounds. */
061      private int rounds;
062    
063      /** The version number. */
064      private int version;
065    
066      /** The word size, in bits. */
067      private int wordSize;
068    
069      // Constructors.
070      // ------------------------------------------------------------------------
071    
072      /**
073       * Create RC5 parameters without an IV.
074       *
075       * @param version  The version number.
076       * @param rounds   The number of rounds.
077       * @param wordSize The size of a word, in bits.
078       */
079      public RC5ParameterSpec(int version, int rounds, int wordSize)
080      {
081        this.version = version;
082        this.rounds = rounds;
083        this.wordSize = wordSize;
084      }
085    
086      /**
087       * Create RC5 parameters with an IV. The bytes in <code>iv</code> in
088       * the range <code>[0, 2*(wordSize/8)-1]</code> are used.
089       *
090       * @param version  The version number.
091       * @param rounds   The number of rounds.
092       * @param wordSize The size of a word, in bits.
093       * @param iv       The IV data.
094       */
095      public RC5ParameterSpec(int version, int rounds, int wordSize, byte[] iv)
096      {
097        this(version, rounds, wordSize, iv, 0);
098      }
099    
100      /**
101       * Create RC5 parameters with an IV. The bytes in <code>iv</code> in
102       * the range <code>[off, off+2*(wordSize/8)-1]</code> are used.
103       *
104       * @param version  The version number.
105       * @param rounds   The number of rounds.
106       * @param wordSize The size of a word, in bits.
107       * @param iv       The IV data.
108       * @param off      From where in the array the IV starts.
109       */
110      public
111      RC5ParameterSpec(int version, int rounds, int wordSize, byte[] iv, int off)
112      {
113        this(version, rounds, wordSize);
114        int ivLength = 2 * (wordSize / 8);
115        if (off < 0)
116          throw new IllegalArgumentException();
117        if (iv.length - off < ivLength)
118          {
119            throw new IllegalArgumentException("IV too short");
120          }
121        this.iv = new byte[ivLength];
122        System.arraycopy(iv, off, this.iv, 0, ivLength);
123      }
124    
125      // Instance methods.
126      // ------------------------------------------------------------------------
127    
128      /**
129       * Return the initializaiton vector, or <code>null</code> if none was
130       * specified.
131       *
132       * @return The IV, or null.
133       */
134      public byte[] getIV()
135      {
136        return iv;
137      }
138    
139      /**
140       * Get the number of rounds.
141       *
142       * @return The number of rounds.
143       */
144      public int getRounds()
145      {
146        return rounds;
147      }
148    
149      /**
150       * Get the version number.
151       *
152       * @return The version number.
153       */
154      public int getVersion()
155      {
156        return version;
157      }
158    
159      /**
160       * Get the word size, in bits.
161       *
162       * @return The word size, in bits.
163       */
164      public int getWordSize()
165      {
166        return wordSize;
167      }
168    
169      public boolean equals(Object o)
170      {
171        if (this == o) return true;
172        byte[] oiv = ((RC5ParameterSpec) o).getIV();
173        if (iv != oiv)
174          {
175            if (iv == null || oiv == null) return false;
176            if (iv.length != oiv.length) return false;
177            for (int i = 0; i < iv.length; i++)
178              {
179                if (iv[i] != oiv[i])
180                  {
181                    return false;
182                  }
183              }
184          }
185        return rounds   == ((RC5ParameterSpec) o).getRounds()
186            && version  == ((RC5ParameterSpec) o).getVersion()
187            && wordSize == ((RC5ParameterSpec) o).getWordSize();
188      }
189    
190      public int hashCode()
191      {
192        int code = rounds + version + wordSize;
193        if (iv != null)
194          {
195            for (int i = 0; i < iv.length; i++)
196              {
197                code += iv[i];
198              }
199          }
200        return code;
201      }
202    }