001    /* IvParameterSpec.java -- A simple wrapper for initialization vectors.
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 an initialization vector. An initialization vector is
045     * necessary for any cipher in any <i>feedback mode</i>, e.g. CBC.
046     *
047     * @author Casey Marshall (csm@gnu.org)
048     */
049    public class IvParameterSpec implements AlgorithmParameterSpec
050    {
051    
052      // Fields.
053      // ------------------------------------------------------------------------
054    
055      /** The IV. */
056      private byte[] iv;
057    
058      // Constructors.
059      // ------------------------------------------------------------------------
060    
061      /**
062       * Create a new initialization vector spec from an entire byte array.
063       *
064       * @param iv The IV bytes.
065       */
066      public IvParameterSpec(byte[] iv)
067      {
068        this(iv, 0, iv.length);
069      }
070    
071      /**
072       * Create a new initialization vector spec from part of a byte array.
073       *
074       * @param iv  The IV bytes.
075       * @param off The offset into the IV bytes.
076       * @param len The number of IV bytes.
077       */
078      public IvParameterSpec(byte[] iv, int off, int len)
079      {
080        this.iv = new byte[len];
081        System.arraycopy(iv, off, this.iv, 0, len);
082      }
083    
084      // Instance methods.
085      // ------------------------------------------------------------------------
086    
087      /**
088       * Returns the IV. This method does not copy the byte array.
089       *
090       * @return The IV.
091       */
092      public byte[] getIV()
093      {
094        return iv;
095      }
096    }