util.java

pos机交易实现源代码 含金融卡交易8583协议实现 开发环境：linux 典型应用：嵌入系统开发 仅供参考

/*
 * Copyright (c) 2000 jPOS.org.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *    "This product includes software developed by the jPOS project 
 *    (http://www.jpos.org/)". Alternately, this acknowledgment may 
 *    appear in the software itself, if and wherever such third-party 
 *    acknowledgments normally appear.
 *
 * 4. The names "jPOS" and "jPOS.org" must not be used to endorse 
 *    or promote products derived from this software without prior 
 *    written permission. For written permission, please contact 
 *    [e-mail].
 *
 * 5. Products derived from this software may not be called "jPOS",
 *    nor may "jPOS" appear in their name, without prior written
 *    permission of the jPOS project.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  
 * IN NO EVENT SHALL THE JPOS PROJECT OR ITS CONTRIBUTORS BE LIABLE FOR 
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the jPOS Project.  For more
 * information please see <http://www.jpos.org/>.
 */

package  org.jpos.security;

import  java.util.Arrays;


/**
 * Util class contains some useful methods.
 * @author Hani S. Kirollos
 * @version $Revision: 1.1 $ $Date: 2002/04/17 20:03:11 $
 */
public class Util {

    /**
     * DES Keys use the LSB as the odd parity bit.  This method can
     * be used enforce correct parity.
     *
     * @param bytes the byte array to set the odd parity on.
     */
    public static void adjustDESParity (byte[] bytes) {
        for (int i = 0; i < bytes.length; i++) {
            int b = bytes[i];
            bytes[i] = (byte)((b & 0xfe) | ((((b >> 1) ^ (b >> 2) ^ (b >> 3) ^ (b >> 4) ^ (b >> 5) ^ (b >> 6) ^ (b >> 7)) ^ 0x01) & 0x01));
        }
    }

    /**
     * DES Keys use the LSB as the odd parity bit.  This method checks
     * whether the parity is adjusted or not
     *
     * @param bytes the byte[] to be checked
     * @return true if parity is adjusted else returns false
     */
    public static boolean isDESParityAdjusted (byte[] bytes) {
        byte[] correct = (byte[])bytes.clone();
        adjustDESParity(correct);
        return  Arrays.equals(bytes, correct);
    }
}