001    /* RC2ParameterSpec.java -- Wrapper for RC2 parameters.
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 for the <a
045     * href="http://www.rsasecurity.com/rsalabs/faq/3-6-2.html">RC2</a>
046     * block cipher ("RC" means either "Rivest Cipher" or "Ron's Code",
047     * depending upon who you ask and when).
048     *
049     * @author Casey Marshall (csm@gnu.org)
050     * @since 1.4
051     */
052    public class RC2ParameterSpec implements AlgorithmParameterSpec
053    {
054    
055      // Constants and fields.
056      // ------------------------------------------------------------------------
057    
058      /** The length of an RC2 IV, in bytes. */
059      private static final int RC2_IV_LENGTH = 8;
060    
061      /** The effective key length, in bits. */
062      private int effectiveKeyBits;
063    
064      /** The initialization vector. */
065      private byte[] iv;
066    
067      // Constructors.
068      // ------------------------------------------------------------------------
069    
070      /**
071       * Create RC2 parameters without an IV.
072       *
073       * @param effectiveKeyBits The number of effective key bits.
074       */
075      public RC2ParameterSpec(int effectiveKeyBits)
076      {
077        this.effectiveKeyBits = effectiveKeyBits;
078      }
079    
080      /**
081       * Create RC2 parameters with an IV.
082       *
083       * @param effectiveKeyBits The number of effective key bits.
084       * @param iv               The IV; the first eight bytes of this array
085       *                         are used.
086       */
087      public RC2ParameterSpec(int effectiveKeyBits, byte[] iv)
088      {
089        this(effectiveKeyBits, iv, 0);
090      }
091    
092      /**
093       * Create RC2 parameters with an IV.
094       *
095       * @param effectiveKeyBits The number of effective key bits.
096       * @param iv               The IV; the first eight bytes of this array
097       *                         after <code>offset</code> are used.
098       * @param offset           From whence to start in the array.
099       */
100      public RC2ParameterSpec(int effectiveKeyBits, byte[] iv, int offset)
101      {
102        if (iv.length - offset < RC2_IV_LENGTH)
103          {
104            throw new IllegalArgumentException("IV too short");
105          }
106        this.effectiveKeyBits = effectiveKeyBits;
107        this.iv = new byte[RC2_IV_LENGTH];
108        System.arraycopy(iv, offset, this.iv, 0, RC2_IV_LENGTH);
109      }
110    
111      // Instance methods.
112      // ------------------------------------------------------------------------
113    
114      /**
115       * Get the number of effective key bits.
116       *
117       * @return The numer of effective key bits.
118       */
119      public int getEffectiveKeyBits()
120      {
121        return effectiveKeyBits;
122      }
123    
124      /**
125       * Return the initialization vector, or <code>null</code> if none was
126       * specified.
127       *
128       * @return The IV, or null.
129       */
130      public byte[] getIV()
131      {
132        return iv;
133      }
134    
135      public boolean equals(Object o)
136      {
137        if (this == o) return true;
138        byte[] oiv = ((RC2ParameterSpec) o).getIV();
139        if (iv != oiv)
140          {
141            if (iv == null || oiv == null) return false;
142            if (iv.length != oiv.length) return false;
143            for (int i = 0; i < iv.length; i++)
144              {
145                if (iv[i] != oiv[i])
146                  {
147                    return false;
148                  }
149              }
150          }
151        return effectiveKeyBits == ((RC2ParameterSpec) o).getEffectiveKeyBits();
152      }
153    
154      public int hashCode()
155      {
156        int code = effectiveKeyBits;
157        if (iv != null)
158          {
159            for (int i = 0; i < RC2_IV_LENGTH; i++)
160              {
161                code += iv[i];
162              }
163          }
164        return code;
165      }
166    }