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	/*
	* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.crypto.provider;

	import java.security.Key;
	import java.security.PublicKey;
	import java.security.PrivateKey;
	import java.security.KeyFactorySpi;
	import java.security.InvalidKeyException;
	import java.security.spec.KeySpec;
	import java.security.spec.InvalidKeySpecException;
	import java.security.spec.X509EncodedKeySpec;
	import java.security.spec.PKCS8EncodedKeySpec;
	import javax.crypto.spec.DHPublicKeySpec;
	import javax.crypto.spec.DHPrivateKeySpec;
	import javax.crypto.spec.DHParameterSpec;

	/**
	* This class implements the Diffie-Hellman key factory of the Sun provider.
	*
	* @author Jan Luehe
	*
	*/
	public final class DHKeyFactory extends KeyFactorySpi {

	/**
	* Empty constructor
	*/
	public DHKeyFactory() {
	}

	/**
	* Generates a public key object from the provided key specification
	* (key material).
	*
	* @param keySpec the specification (key material) of the public key
	*
	* @return the public key
	*
	* @exception InvalidKeySpecException if the given key specification
	* is inappropriate for this key factory to produce a public key.
	*/
	protected PublicKey engineGeneratePublic(KeySpec keySpec)
	throws InvalidKeySpecException
	{
	try {
	if (keySpec instanceof DHPublicKeySpec) {
	DHPublicKeySpec dhPubKeySpec = (DHPublicKeySpec)keySpec;
	return new DHPublicKey(dhPubKeySpec.getY(),
	dhPubKeySpec.getP(),
	dhPubKeySpec.getG());

	} else if (keySpec instanceof X509EncodedKeySpec) {
	return new DHPublicKey
	(((X509EncodedKeySpec)keySpec).getEncoded());

	} else {
	throw new InvalidKeySpecException
	("Inappropriate key specification");
	}
	} catch (InvalidKeyException e) {
	throw new InvalidKeySpecException
	("Inappropriate key specification", e);
	}
	}

	/**
	* Generates a private key object from the provided key specification
	* (key material).
	*
	* @param keySpec the specification (key material) of the private key
	*
	* @return the private key
	*
	* @exception InvalidKeySpecException if the given key specification
	* is inappropriate for this key factory to produce a private key.
	*/
	protected PrivateKey engineGeneratePrivate(KeySpec keySpec)
	throws InvalidKeySpecException
	{
	try {
	if (keySpec instanceof DHPrivateKeySpec) {
	DHPrivateKeySpec dhPrivKeySpec = (DHPrivateKeySpec)keySpec;
	return new DHPrivateKey(dhPrivKeySpec.getX(),
	dhPrivKeySpec.getP(),
	dhPrivKeySpec.getG());

	} else if (keySpec instanceof PKCS8EncodedKeySpec) {
	return new DHPrivateKey
	(((PKCS8EncodedKeySpec)keySpec).getEncoded());

	} else {
	throw new InvalidKeySpecException
	("Inappropriate key specification");
	}
	} catch (InvalidKeyException e) {
	throw new InvalidKeySpecException
	("Inappropriate key specification", e);
	}
	}

	/**
	* Returns a specification (key material) of the given key object
	* in the requested format.
	*
	* @param key the key
	*
	* @param keySpec the requested format in which the key material shall be
	* returned
	*
	* @return 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 processed
	* (e.g., the given key has an unrecognized algorithm or format).
	*/
	protected <T extends KeySpec>
	T engineGetKeySpec(Key key, Class<T> keySpec)
	throws InvalidKeySpecException {
	DHParameterSpec params;

	if (key instanceof javax.crypto.interfaces.DHPublicKey) {

	if (DHPublicKeySpec.class.isAssignableFrom(keySpec)) {
	javax.crypto.interfaces.DHPublicKey dhPubKey
	= (javax.crypto.interfaces.DHPublicKey) key;
	params = dhPubKey.getParams();
	return keySpec.cast(new DHPublicKeySpec(dhPubKey.getY(),
	params.getP(),
	params.getG()));

	} else if (X509EncodedKeySpec.class.isAssignableFrom(keySpec)) {
	return keySpec.cast(new X509EncodedKeySpec(key.getEncoded()));

	} else {
	throw new InvalidKeySpecException
	("Inappropriate key specification");
	}

	} else if (key instanceof javax.crypto.interfaces.DHPrivateKey) {

	if (DHPrivateKeySpec.class.isAssignableFrom(keySpec)) {
	javax.crypto.interfaces.DHPrivateKey dhPrivKey
	= (javax.crypto.interfaces.DHPrivateKey)key;
	params = dhPrivKey.getParams();
	return keySpec.cast(new DHPrivateKeySpec(dhPrivKey.getX(),
	params.getP(),
	params.getG()));

	} else if (PKCS8EncodedKeySpec.class.isAssignableFrom(keySpec)) {
	return keySpec.cast(new PKCS8EncodedKeySpec(key.getEncoded()));

	} else {
	throw new InvalidKeySpecException
	("Inappropriate key specification");
	}

	} else {
	throw new InvalidKeySpecException("Inappropriate key type");
	}
	}

	/**
	* Translates a 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
	*
	* @return the translated key
	*
	* @exception InvalidKeyException if the given key cannot be processed by
	* this key factory.
	*/
	protected Key engineTranslateKey(Key key)
	throws InvalidKeyException
	{
	try {

	if (key instanceof javax.crypto.interfaces.DHPublicKey) {
	// Check if key originates from this factory
	if (key instanceof com.sun.crypto.provider.DHPublicKey) {
	return key;
	}
	// Convert key to spec
	DHPublicKeySpec dhPubKeySpec
	= engineGetKeySpec(key, DHPublicKeySpec.class);
	// Create key from spec, and return it
	return engineGeneratePublic(dhPubKeySpec);

	} else if (key instanceof javax.crypto.interfaces.DHPrivateKey) {
	// Check if key originates from this factory
	if (key instanceof com.sun.crypto.provider.DHPrivateKey) {
	return key;
	}
	// Convert key to spec
	DHPrivateKeySpec dhPrivKeySpec
	= engineGetKeySpec(key, DHPrivateKeySpec.class);
	// Create key from spec, and return it
	return engineGeneratePrivate(dhPrivKeySpec);

	} else {
	throw new InvalidKeyException("Wrong algorithm type");
	}

	} catch (InvalidKeySpecException e) {
	throw new InvalidKeyException("Cannot translate key", e);
	}
	}
	}

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