package gnu.crypto.key;  // -*- c-basic-offset: 3 -*-

// ---------------------------------------------------------------------------
// $Id: GnuSecretKey.java,v 1.2 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING.  If not, write to the
//
//    Free Software Foundation Inc.,
//    51 Franklin Street, Fifth Floor,
//    Boston, MA 02110-1301
//    USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library.  Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module.  An independent module is a module which is
// not derived from or based on this library.  If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so.  If you do not wish to
// do so, delete this exception statement from your version.
//
// ---------------------------------------------------------------------------

import gnu.crypto.util.Util;
import java.security.Key;

/**
 * A secret key composed of a sequence of raw, unformatted octets. This class
 * is analogous to the {@link javax.crypto.spec.SecretKeySpec} class, but is
 * provided for platforms that do not or cannot contain that class.
 *
 * @version $Revision: 1.2 $
 */
public class GnuSecretKey implements Key
{

   // Field.
   // ------------------------------------------------------------------------

   private final byte[] key;
   private final String algorithm;

   // Constructors.
   // ------------------------------------------------------------------------

   /**
    * Creates a new secret key. The supplied byte array is copied by this
    * constructor.
    *
    * @param key The raw, secret key.
    * @param algorithm The algorithm name, which can be null or empty.
    */
   public GnuSecretKey(byte[] key, String algorithm)
   {
      this(key, 0, key.length, algorithm);
   }

   /**
    * Creates a new secret key from a portion of a byte array.
    *
    * @param key The raw, secret key.
    * @param offset The offset at which the key begins.
    * @param length The number of bytes that comprise the key.
    * @param algorithm The algorithm name, which can be null or empty.
    */
   public GnuSecretKey(byte[] key, int offset, int length, String algorithm)
   {
      this.key = new byte[length];
      System.arraycopy(key, offset, this.key, 0, length);
      this.algorithm = algorithm;
   }

   // Instance methods.
   // ------------------------------------------------------------------------

   /**
    * Returns the algorithm name, if any.
    *
    * @return The algorithm name.
    */
   public String getAlgorithm()
   {
      return null;
   }

   /**
    * Returns the encoded key, which is merely the byte array this class was
    * created with. A reference to the internal byte array is returned, so the
    * caller can delete this key from memory by modifying the returned array.
    *
    * @return The raw key.
    */
   public byte[] getEncoded()
   {
      return key;
   }

   /**
    * Returns the string "RAW".
    *
    * @return The string "RAW".
    */
   public String getFormat()
   {
      return "RAW";
   }

   public boolean equals(Object o)
   {
      if (!(o instanceof GnuSecretKey)) {
         return false;
      }
      if (key.length != ((GnuSecretKey) o).key.length) {
         return false;
      }
      byte[] key2 = ((GnuSecretKey) o).key;
      for (int i = 0; i < key.length; i++) {
         if (key[i] != key2[i]) {
            return false;
         }
      }
      return true;
   }

   public String toString()
   {
      return "GnuSecretKey [ " + algorithm + " " + Util.toString(key) + " ]";
   }
}
