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	/*
	* Copyright (c) 1997, 2011, 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 javax.crypto.spec;

	import java.security.InvalidKeyException;

	/**
	* This class specifies a DES key.
	*
	* @author Jan Luehe
	*
	* @since 1.4
	*/
	public class DESKeySpec implements java.security.spec.KeySpec {

	/**
	* The constant which defines the length of a DES key in bytes.
	*/
	public static final int DES_KEY_LEN = 8;

	private byte[] key;

	/*
	* Weak/semi-weak keys copied from FIPS 74.
	*
	* "...The first 6 keys have duals different than themselves, hence
	* each is both a key and a dual giving 12 keys with duals. The last
	* four keys equal their duals, and are called self-dual keys..."
	*
	* 1. E001E001F101F101 01E001E001F101F1
	* 2. FE1FFE1FFEOEFEOE 1FFE1FFEOEFEOEFE
	* 3. E01FE01FF10EF10E 1FE01FEOOEF10EF1
	* 4. 01FE01FE01FE01FE FE01FE01FE01FE01
	* 5. 011F011F010E010E 1F011F010E010E01
	* 6. E0FEE0FEF1FEF1FE FEE0FEE0FEF1FEF1
	* 7. 0101010101010101 0101010101010101
	* 8. FEFEFEFEFEFEFEFE FEFEFEFEFEFEFEFE
	* 9. E0E0E0E0F1F1F1F1 E0E0E0E0F1F1F1F1
	* 10. 1F1F1F1F0E0E0E0E 1F1F1F1F0E0E0E0E
	*/
	private static final byte[][] WEAK_KEYS = {

	{ (byte)0x01, (byte)0x01, (byte)0x01, (byte)0x01, (byte)0x01,
	(byte)0x01, (byte)0x01, (byte)0x01 },

	{ (byte)0xFE, (byte)0xFE, (byte)0xFE, (byte)0xFE, (byte)0xFE,
	(byte)0xFE, (byte)0xFE, (byte)0xFE },

	{ (byte)0x1F, (byte)0x1F, (byte)0x1F, (byte)0x1F, (byte)0x0E,
	(byte)0x0E, (byte)0x0E, (byte)0x0E },

	{ (byte)0xE0, (byte)0xE0, (byte)0xE0, (byte)0xE0, (byte)0xF1,
	(byte)0xF1, (byte)0xF1, (byte)0xF1 },

	{ (byte)0x01, (byte)0xFE, (byte)0x01, (byte)0xFE, (byte)0x01,
	(byte)0xFE, (byte)0x01, (byte)0xFE },

	{ (byte)0x1F, (byte)0xE0, (byte)0x1F, (byte)0xE0, (byte)0x0E,
	(byte)0xF1, (byte)0x0E, (byte)0xF1 },

	{ (byte)0x01, (byte)0xE0, (byte)0x01, (byte)0xE0, (byte)0x01,
	(byte)0xF1, (byte)0x01, (byte)0xF1 },

	{ (byte)0x1F, (byte)0xFE, (byte)0x1F, (byte)0xFE, (byte)0x0E,
	(byte)0xFE, (byte)0x0E, (byte)0xFE },

	{ (byte)0x01, (byte)0x1F, (byte)0x01, (byte)0x1F, (byte)0x01,
	(byte)0x0E, (byte)0x01, (byte)0x0E },

	{ (byte)0xE0, (byte)0xFE, (byte)0xE0, (byte)0xFE, (byte)0xF1,
	(byte)0xFE, (byte)0xF1, (byte)0xFE },

	{ (byte)0xFE, (byte)0x01, (byte)0xFE, (byte)0x01, (byte)0xFE,
	(byte)0x01, (byte)0xFE, (byte)0x01 },

	{ (byte)0xE0, (byte)0x1F, (byte)0xE0, (byte)0x1F, (byte)0xF1,
	(byte)0x0E, (byte)0xF1, (byte)0x0E },

	{ (byte)0xE0, (byte)0x01, (byte)0xE0, (byte)0x01, (byte)0xF1,
	(byte)0x01, (byte)0xF1, (byte)0x01 },

	{ (byte)0xFE, (byte)0x1F, (byte)0xFE, (byte)0x1F, (byte)0xFE,
	(byte)0x0E, (byte)0xFE, (byte)0x0E },

	{ (byte)0x1F, (byte)0x01, (byte)0x1F, (byte)0x01, (byte)0x0E,
	(byte)0x01, (byte)0x0E, (byte)0x01 },

	{ (byte)0xFE, (byte)0xE0, (byte)0xFE, (byte)0xE0, (byte)0xFE,
	(byte)0xF1, (byte)0xFE, (byte)0xF1 }
	};

	/**
	* Creates a DESKeySpec object using the first 8 bytes in
	* <code>key</code> as the key material for the DES key.
	*
	* <p> The bytes that constitute the DES key are those between
	* <code>key[0]</code> and <code>key[7]</code> inclusive.
	*
	* @param key the buffer with the DES key material. The first 8 bytes
	* of the buffer are copied to protect against subsequent modification.
	*
	* @exception NullPointerException if the given key material is
	* <code>null</code>
	* @exception InvalidKeyException if the given key material is shorter
	* than 8 bytes.
	*/
	public DESKeySpec(byte[] key) throws InvalidKeyException {
	this(key, 0);
	}

	/**
	* Creates a DESKeySpec object using the first 8 bytes in
	* <code>key</code>, beginning at <code>offset</code> inclusive,
	* as the key material for the DES key.
	*
	* <p> The bytes that constitute the DES key are those between
	* <code>key[offset]</code> and <code>key[offset+7]</code> inclusive.
	*
	* @param key the buffer with the DES key material. The first 8 bytes
	* of the buffer beginning at <code>offset</code> inclusive are copied
	* to protect against subsequent modification.
	* @param offset the offset in <code>key</code>, where the DES key
	* material starts.
	*
	* @exception NullPointerException if the given key material is
	* <code>null</code>
	* @exception InvalidKeyException if the given key material, starting at
	* <code>offset</code> inclusive, is shorter than 8 bytes.
	*/
	public DESKeySpec(byte[] key, int offset) throws InvalidKeyException {
	if (key.length - offset < DES_KEY_LEN) {
	throw new InvalidKeyException("Wrong key size");
	}
	this.key = new byte[DES_KEY_LEN];
	System.arraycopy(key, offset, this.key, 0, DES_KEY_LEN);
	}

	/**
	* Returns the DES key material.
	*
	* @return the DES key material. Returns a new array
	* each time this method is called.
	*/
	public byte[] getKey() {
	return this.key.clone();
	}

	/**
	* Checks if the given DES key material, starting at <code>offset</code>
	* inclusive, is parity-adjusted.
	*
	* @param key the buffer with the DES key material.
	* @param offset the offset in <code>key</code>, where the DES key
	* material starts.
	*
	* @return true if the given DES key material is parity-adjusted, false
	* otherwise.
	*
	* @exception InvalidKeyException if the given key material is
	* <code>null</code>, or starting at <code>offset</code> inclusive, is
	* shorter than 8 bytes.
	*/
	public static boolean isParityAdjusted(byte[] key, int offset)
	throws InvalidKeyException {
	if (key == null) {
	throw new InvalidKeyException("null key");
	}
	if (key.length - offset < DES_KEY_LEN) {
	throw new InvalidKeyException("Wrong key size");
	}

	for (int i = 0; i < DES_KEY_LEN; i++) {
	int k = Integer.bitCount(key[offset++] & 0xff);
	if ((k & 1) == 0) {
	return false;
	}
	}

	return true;
	}

	/**
	* Checks if the given DES key material is weak or semi-weak.
	*
	* @param key the buffer with the DES key material.
	* @param offset the offset in <code>key</code>, where the DES key
	* material starts.
	*
	* @return true if the given DES key material is weak or semi-weak, false
	* otherwise.
	*
	* @exception InvalidKeyException if the given key material is
	* <code>null</code>, or starting at <code>offset</code> inclusive, is
	* shorter than 8 bytes.
	*/
	public static boolean isWeak(byte[] key, int offset)
	throws InvalidKeyException {
	if (key == null) {
	throw new InvalidKeyException("null key");
	}
	if (key.length - offset < DES_KEY_LEN) {
	throw new InvalidKeyException("Wrong key size");
	}
	for (int i = 0; i < WEAK_KEYS.length; i++) {
	boolean found = true;
	for (int j = 0; j < DES_KEY_LEN && found == true; j++) {
	if (WEAK_KEYS[i][j] != key[j+offset]) {
	found = false;
	}
	}
	if (found == true) {
	return found;
	}
	}
	return false;
	}
	}

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