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	/*
	* Copyright (c) 2005, 2009, 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.nio.ByteBuffer;

	import javax.crypto.MacSpi;
	import javax.crypto.SecretKey;
	import java.security.*;
	import java.security.spec.AlgorithmParameterSpec;

	import static com.sun.crypto.provider.TlsPrfGenerator.genPad;

	/**
	* This file contains the code for the SslMacMD5 and SslMacSHA1 implementations.
	* The SSL 3.0 MAC is a variation of the HMAC algorithm.
	*
	* Note that we don't implement Cloneable as that is not needed for SSL.
	*
	* @author Andreas Sterbenz
	* @since 1.6
	*/
	final class SslMacCore {

	private final MessageDigest md;
	private final byte[] pad1, pad2;

	private boolean first; // Is this the first data to be processed?
	private byte[] secret;

	/**
	* Standard constructor, creates a new SslMacCore instance instantiating
	* a MessageDigest of the specified name.
	*/
	SslMacCore(String digestAlgorithm, byte[] pad1, byte[] pad2)
	throws NoSuchAlgorithmException {
	md = MessageDigest.getInstance(digestAlgorithm);
	this.pad1 = pad1;
	this.pad2 = pad2;
	first = true;
	}

	/**
	* Returns the length of the Mac in bytes.
	*
	* @return the Mac length in bytes.
	*/
	int getDigestLength() {
	return md.getDigestLength();
	}

	/**
	* Initializes the Mac with the given secret key and algorithm parameters.
	*
	* @param key the secret key.
	* @param params the algorithm parameters.
	*
	* @exception InvalidKeyException if the given key is inappropriate for
	* initializing this MAC.
	* @exception InvalidAlgorithmParameterException if the given algorithm
	* parameters are inappropriate for this MAC.
	*/
	void init(Key key, AlgorithmParameterSpec params)
	throws InvalidKeyException, InvalidAlgorithmParameterException {

	if (params != null) {
	throw new InvalidAlgorithmParameterException
	("SslMac does not use parameters");
	}

	if (!(key instanceof SecretKey)) {
	throw new InvalidKeyException("Secret key expected");
	}

	secret = key.getEncoded();
	if (secret == null \|\| secret.length == 0) {
	throw new InvalidKeyException("Missing key data");
	}

	reset();
	}

	/**
	* Processes the given byte.
	*
	* @param input the input byte to be processed.
	*/
	void update(byte input) {
	if (first == true) {
	// compute digest for 1st pass; start with inner pad
	md.update(secret);
	md.update(pad1);
	first = false;
	}

	// add the passed byte to the inner digest
	md.update(input);
	}

	/**
	* Processes the first <code>len</code> bytes in <code>input</code>,
	* starting at <code>offset</code>.
	*
	* @param input the input buffer.
	* @param offset the offset in <code>input</code> where the input starts.
	* @param len the number of bytes to process.
	*/
	void update(byte input[], int offset, int len) {
	if (first == true) {
	// compute digest for 1st pass; start with inner pad
	md.update(secret);
	md.update(pad1);
	first = false;
	}

	// add the selected part of an array of bytes to the inner digest
	md.update(input, offset, len);
	}

	void update(ByteBuffer input) {
	if (first == true) {
	// compute digest for 1st pass; start with inner pad
	md.update(secret);
	md.update(pad1);
	first = false;
	}

	md.update(input);
	}

	/**
	* Completes the Mac computation and resets the Mac for further use,
	* maintaining the secret key that the Mac was initialized with.
	*
	* @return the Mac result.
	*/
	byte[] doFinal() {
	if (first == true) {
	// compute digest for 1st pass; start with inner pad
	md.update(secret);
	md.update(pad1);
	} else {
	first = true;
	}

	try {
	// finish the inner digest
	byte[] tmp = md.digest();

	// compute digest for 2nd pass; start with outer pad
	md.update(secret);
	md.update(pad2);
	// add result of 1st hash
	md.update(tmp);

	md.digest(tmp, 0, tmp.length);
	return tmp;
	} catch (DigestException e) {
	// should never occur
	throw new ProviderException(e);
	}
	}

	/**
	* Resets the Mac for further use, maintaining the secret key that the
	* Mac was initialized with.
	*/
	void reset() {
	if (first == false) {
	md.reset();
	first = true;
	}
	}

	// nested static class for the SslMacMD5 implementation
	public static final class SslMacMD5 extends MacSpi {
	private final SslMacCore core;
	public SslMacMD5() throws NoSuchAlgorithmException {
	core = new SslMacCore("MD5", md5Pad1, md5Pad2);
	}
	protected int engineGetMacLength() {
	return core.getDigestLength();
	}
	protected void engineInit(Key key, AlgorithmParameterSpec params)
	throws InvalidKeyException, InvalidAlgorithmParameterException {
	core.init(key, params);
	}
	protected void engineUpdate(byte input) {
	core.update(input);
	}
	protected void engineUpdate(byte input[], int offset, int len) {
	core.update(input, offset, len);
	}
	protected void engineUpdate(ByteBuffer input) {
	core.update(input);
	}
	protected byte[] engineDoFinal() {
	return core.doFinal();
	}
	protected void engineReset() {
	core.reset();
	}

	static final byte[] md5Pad1 = genPad((byte)0x36, 48);
	static final byte[] md5Pad2 = genPad((byte)0x5c, 48);
	}

	// nested static class for the SslMacMD5 implementation
	public static final class SslMacSHA1 extends MacSpi {
	private final SslMacCore core;
	public SslMacSHA1() throws NoSuchAlgorithmException {
	core = new SslMacCore("SHA", shaPad1, shaPad2);
	}
	protected int engineGetMacLength() {
	return core.getDigestLength();
	}
	protected void engineInit(Key key, AlgorithmParameterSpec params)
	throws InvalidKeyException, InvalidAlgorithmParameterException {
	core.init(key, params);
	}
	protected void engineUpdate(byte input) {
	core.update(input);
	}
	protected void engineUpdate(byte input[], int offset, int len) {
	core.update(input, offset, len);
	}
	protected void engineUpdate(ByteBuffer input) {
	core.update(input);
	}
	protected byte[] engineDoFinal() {
	return core.doFinal();
	}
	protected void engineReset() {
	core.reset();
	}

	static final byte[] shaPad1 = genPad((byte)0x36, 40);
	static final byte[] shaPad2 = genPad((byte)0x5c, 40);
	}

	}

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