package au.net.aba.crypto.provider;

/*
 * $Id: PBEKeyFactory.java,v 1.3 1999/01/28 04:47:28 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/PBEKeyFactory.java,v $
 * $Revision: 1.3 $
 * $Date: 1999/01/28 04:47:28 $
 * $State: Exp $
 */

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

/**
 * This class is used to convert password based keys into a format
 * usable by the ABA provider.  This class can convert PBEKeySpec
 * objects into an ABA PBEKey and visa versa.
 * <p>
 * This class should not be instantiated directly, instead use the
 * java.security.KeyFactory interface.
 *
 * @see java.security.KeyFactory
 */
public class PBEKeyFactory extends SecretKeyFactorySpi
{
	public final static String ident = "$Id: PBEKeyFactory.java,v 1.3 1999/01/28 04:47:28 leachbj Exp $";

	/**
	 * Generates a PBE SecretKey object from the provided key specification
	 * (key material).  This class supports the PBEKeySpec KeySpec class.
	 *
	 * @returns The secret key.
	 * @exception InvalidKeySpecException  The provided KeySpec was not
	 * 	a PBEKeySpec KeySpec.
	 */
	protected SecretKey engineGenerateSecret(
		KeySpec keySpec)
		throws InvalidKeySpecException
	{
		if (keySpec == null || !(keySpec instanceof PBEKeySpec))
		{
			throw new InvalidKeySpecException("Invalid KeySpec");
		}

		char[] password = ((PBEKeySpec)keySpec).getPassword();
		
		return new PBEKey(password);
	}
	/**
	 * Returns a specification (key material) of the given key object in
	 * the requested format.  Currently only the PBEKeySpec KeySpec
	 * class is supported.
	 *
	 * @param key the key 
	 * @param keySpec the requested format in which the key material shall
	 *		be returned, must be PBEKeySpec.class
	 * @returns the underlying key specification (key material) in the
	 *		requested format
	 * @exception InvalidKeySpecException if the provided key
	 *	is not a PBEKey or the requested KeySpec is not a
	 * 	PBEKeySpec.
	 */
	protected KeySpec engineGetKeySpec(
		SecretKey key,
		Class keySpec)
		throws InvalidKeySpecException
	{
		if (key instanceof PBEKey)
		{
			if (keySpec.equals(PBEKeySpec.class))
			{
				PBEKey pbeKey = (PBEKey)key;
				
				return new PBEKeySpec(pbeKey.getPassword());
			}
		}

		throw new InvalidKeySpecException(
			"Unsupported KeySpec requested.");
	}
	/**
	 * Translates a PBE 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("PBE"))
		{
			throw new InvalidKeyException("not a PBE key");
		}
		
		// To do this requires translating bytes into chars!
		byte[] bytes = key.getEncoded();
		char[] pwd = new char[bytes.length];
		for (int i = 0; i < pwd.length; i++)
			pwd[i] = (char)bytes[i];
		return new PBEKey(pwd);
	}
}