Java example source code file (DESedeKeySpec.java)

This example Java source code file (DESedeKeySpec.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

des_ede_key_len, desedekeyspec, invalidkeyexception, security, wrong

The DESedeKeySpec.java Java example source code

/*
 * 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-EDE ("triple-DES") key.
 *
 * @author Jan Luehe
 *
 * @since 1.4
 */
public class DESedeKeySpec implements java.security.spec.KeySpec {

    /**
     * The constant which defines the length of a DESede key in bytes.
     */
    public static final int DES_EDE_KEY_LEN = 24;

    private byte[] key;

    /**
     * Creates a DESedeKeySpec object using the first 24 bytes in
     * <code>key as the key material for the DES-EDE key.
     *
     * <p> The bytes that constitute the DES-EDE key are those between
     * <code>key[0] and key[23] inclusive
     *
     * @param key the buffer with the DES-EDE key material. The first
     * 24 bytes of the buffer are copied to protect against subsequent
     * modification.
     *
     * @exception NullPointerException if <code>key is null.
     * @exception InvalidKeyException if the given key material is shorter
     * than 24 bytes.
     */
    public DESedeKeySpec(byte[] key) throws InvalidKeyException {
        this(key, 0);
    }

    /**
     * Creates a DESedeKeySpec object using the first 24 bytes in
     * <code>key, beginning at offset inclusive,
     * as the key material for the DES-EDE key.
     *
     * <p> The bytes that constitute the DES-EDE key are those between
     * <code>key[offset] and key[offset+23] inclusive.
     *
     * @param key the buffer with the DES-EDE key material. The first
     * 24 bytes of the buffer beginning at <code>offset inclusive
     * are copied to protect against subsequent modification.
     * @param offset the offset in <code>key, where the DES-EDE key
     * material starts.
     *
     * @exception NullPointerException if <code>key is null.
     * @exception InvalidKeyException if the given key material, starting at
     * <code>offset inclusive, is shorter than 24 bytes
     */
    public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException {
        if (key.length - offset < 24) {
            throw new InvalidKeyException("Wrong key size");
        }
        this.key = new byte[24];
        System.arraycopy(key, offset, this.key, 0, 24);
    }

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

    /**
     * Checks if the given DES-EDE key, starting at <code>offset
     * inclusive, is parity-adjusted.
     *
     * @param key    a byte array which holds the key value
     * @param offset the offset into the byte array
     * @return true if the given DES-EDE key is parity-adjusted, false
     * otherwise
     *
     * @exception NullPointerException if <code>key is null.
     * @exception InvalidKeyException if the given key material, starting at
     * <code>offset inclusive, is shorter than 24 bytes
     */
    public static boolean isParityAdjusted(byte[] key, int offset)
        throws InvalidKeyException {
            if (key.length - offset < 24) {
                throw new InvalidKeyException("Wrong key size");
            }
            if (DESKeySpec.isParityAdjusted(key, offset) == false
                || DESKeySpec.isParityAdjusted(key, offset + 8) == false
                || DESKeySpec.isParityAdjusted(key, offset + 16) == false) {
                return false;
            }
            return true;
    }
}