deskeyfactory.java

面向应用的智能安全代理平台和工具包是一个综合网络应用的安全共性需求而设计和实现的一个通用性的网络信息安全应用支撑平台

package au.net.aba.crypto.provider;

/*
 * $Id: DESKeyFactory.java,v 1.12 1999/02/18 06:28:48 leachbj Exp $
 * $Author: leachbj $
 *
 * Copyright (C) 1996-1998 Australian Business Access Pty Ltd.
 * All rights reserved.
 * 
 * Use, modification, copying and distribution of this software is subject the
 * terms and conditions of the ABA Public Licence. See the file
 * "PUBLIC_LICENCE" for additional information.
 *
 * If you have not received a copy of the Public Licence, you must destroy all
 * copies of this file immediately. 
 *
 * $Source: /aba/CVSROOT/jdk1.1/src/au.net.aba/crypto/provider/DESKeyFactory.java,v $
 * $Revision: 1.12 $
 * $Date: 1999/02/18 06:28:48 $
 * $State: Exp $
 */

import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.security.InvalidKeyException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactorySpi;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * This class is used to convert DES keys into a format usable by the
 * ABA provider.  The supported KeySpec classes are DESKeySpec and
 * SecretKeySpec.  In the case of the SecretKeySpec the key data must
 * be at least 8 bytes long and there must be no encoding on the key
 * data.  The supported Key class is DESKey.
 * <p>
 * This class should not be instantiated directly, instead use the
 * java.security.KeyFactory interface.
 *
 * @see java.security.KeyFactory
 */
public class DESKeyFactory extends SecretKeyFactorySpi
{
	public final static String ident = "$Id: DESKeyFactory.java,v 1.12 1999/02/18 06:28:48 leachbj Exp $";

	/**
	 * Generates a DES SecretKey object from the provided key specification
	 * (key material).  This class supports the DESKeySpec KeySpec and
	 * SecretKeySpec classes.
	 *
	 * @returns The secret key.
	 * @exception InvalidKeySpecException  The provided KeySpec was not
	 * 	a DESKeySpec or SecretKeySpec instance.
	 */
	protected SecretKey engineGenerateSecret(
		KeySpec keySpec)
		throws InvalidKeySpecException
	{
		if (keySpec instanceof DESKeySpec)
		{
			return new DESKey(((DESKeySpec)keySpec).getKey());
		}
		else if (keySpec instanceof SecretKeySpec)
		{
			SecretKeySpec skspec = (SecretKeySpec)keySpec;

			if (!"DES".equals(skspec.getAlgorithm()))
			{
				throw new InvalidKeySpecException(
					"SecretKeySpec not for DES");
			}
			if (!"RAW".equals(skspec.getFormat()))
			{
				throw new InvalidKeySpecException(
					"Unknown encoding format in KeySpec");
			}

			return new DESKey(skspec.getEncoded());
		}

		throw new InvalidKeySpecException(
			keySpec.getClass().getName()
			+ " not valid for DES.");
	}
	/**
	 * Returns a specification (key material) of the given key object in
	 * the requested format. 
	 * <p>
	 * Currently supports conversion from ABA's DES keys to SecretKeySpec
	 * or DESKeySpec instances.
	 *
	 * @param key the key 
	 * @param keySpec the requested format in which the key material shall
	 *		be returned 
	 * @returns the underlying key specification (key material) in the
	 *		requested format
	 * @exception InvalidKeySpecException if the requested key
	 *	specification is inappropriate for the given key, or the given
	 *	key cannot be dealt with (e.g., the given key has an
	 *	unrecognised format). 
	 */
	protected KeySpec engineGetKeySpec(
		SecretKey key,
		Class keySpec)
		throws InvalidKeySpecException
	{
		if (key instanceof DESKey)
		{
			if (SecretKeySpec.class.isAssignableFrom(keySpec))
			{
				return new SecretKeySpec(key.getEncoded(),
					"DES");
			}
			else if (DESKeySpec.class.isAssignableFrom(keySpec))
			{
				try
				{
					return new DESKeySpec(key.getEncoded());
				}
				catch (InvalidKeyException e)
				{
					throw new InvalidKeySpecException(
						e.getMessage());
				}
			}
		}

		throw new InvalidKeySpecException("not implemented");
	}
	/**
	 * Translates a DES key object, whose provider may be unknown or
	 * potentially untrusted, into a corresponding key object of this key
	 * factory. 
	 *
	 * @param key - the key whose provider is unknown or untrusted 
	 * @returns the translated key 
	 * @exception InvalidKeyException if the given key cannot be processed
	 * 	by this key factory. 
	 */
	protected SecretKey engineTranslateKey(
		SecretKey key)
		throws InvalidKeyException
	{
		if (!key.getAlgorithm().equals("DES"))
		{
			throw new InvalidKeyException("not a DES key");
		}

		return new DESKey(key.getEncoded());
	}
}