}
import java.security.*;import javax.crypto.Cipher;import javax.crypto.SecretKey;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESKeySpec;/** * Copyright 2007 GuangZhou Cotel Co. Ltd. * All right reserved. * DES加密解密类. * @author <a href="http://www.coder55.com/mailto:xiexingxing1121@126.com" mce_href="http://www.coder55.com/mailto:xiexingxing1121@126.com">AmigoXie</a> * @version 1.0 * Creation date: 2007-7-31 - 上午11:59:28 */public class Des { /** 加密、解密key. */ private static final String PASSWORD_CRYPT_KEY = "kEHrDooxWHCWtfeSxvDvgqZq"; /** 加密算法,可用 DES,DESede,Blowfish. */ private final static String ALGORITHM = "DES"; public static void main(String[] args) throws Exception { String md5Password = "202cb962ac59075b964b07152d234b70"; String str = Des.encrypt(md5Password); System.out.println("str: " + str); str = Des.decrypt(str); System.out.println("str: " + str); } /** * 对数据进行DES加密. * @param data 待进行DES加密的数据 * @return 返回经过DES加密后的数据 * @throws Exception * @author <a href="http://www.coder55.com/mailto:xiexingxing1121@126.com" mce_href="http://www.coder55.com/mailto:xiexingxing1121@126.com">AmigoXie</a> * Creation date: 2007-7-31 - 下午12:06:24 */ public final static String decrypt(String data) throws Exception { return new String(decrypt(hex2byte(data.getBytes()), PASSWORD_CRYPT_KEY.getBytes())); } /** * 对用DES加密过的数据进行解密. * @param data DES加密数据 * @return 返回解密后的数据 * @throws Exception * @author <a href="http://www.coder55.com/mailto:xiexingxing1121@126.com" mce_href="http://www.coder55.com/mailto:xiexingxing1121@126.com">AmigoXie</a> * Creation date: 2007-7-31 - 下午12:07:54 */ public final static String encrypt(String data) throws Exception { return byte2hex(encrypt(data.getBytes(), PASSWORD_CRYPT_KEY .getBytes())); } /** * 用指定的key对数据进行DES加密. * @param data 待加密的数据 * @param key DES加密的key * @return 返回DES加密后的数据 * @throws Exception * @author <a href="http://www.coder55.com/mailto:xiexingxing1121@126.com" mce_href="http://www.coder55.com/mailto:xiexingxing1121@126.com">AmigoXie</a> * Creation date: 2007-7-31 - 下午12:09:03 */ private static byte[] encrypt(byte[] data, byte[] key) throws Exception { // DES算法要求有一个可信任的随机数源 SecureRandom sr = new SecureRandom(); // 从原始密匙数据创建DESKeySpec对象 DESKeySpec dks = new DESKeySpec(key); // 创建一个密匙工厂，然后用它把DESKeySpec转换成 // 一个SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher对象实际完成加密操作 Cipher cipher = Cipher.getInstance(ALGORITHM); // 用密匙初始化Cipher对象 cipher.init(Cipher.ENCRYPT_MODE, securekey, sr); // 现在，获取数据并加密 // 正式执行加密操作 return cipher.doFinal(data); } /** * 用指定的key对数据进行DES解密. * @param data 待解密的数据 * @param key DES解密的key * @return 返回DES解密后的数据 * @throws Exception * @author <a href="http://www.coder55.com/mailto:xiexingxing1121@126.com" mce_href="http://www.coder55.com/mailto:xiexingxing1121@126.com">AmigoXie</a> * Creation date: 2007-7-31 - 下午12:10:34 */ private static byte[] decrypt(byte[] data, byte[] key) throws Exception { // DES算法要求有一个可信任的随机数源 SecureRandom sr = new SecureRandom(); // 从原始密匙数据创建一个DESKeySpec对象 DESKeySpec dks = new DESKeySpec(key); // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成 // 一个SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher对象实际完成解密操作 Cipher cipher = Cipher.getInstance(ALGORITHM); // 用密匙初始化Cipher对象 cipher.init(Cipher.DECRYPT_MODE, securekey, sr); // 现在，获取数据并解密 // 正式执行解密操作 return cipher.doFinal(data); } public static byte[] hex2byte(byte[] b) { if ((b.length % 2) != 0) throw new IllegalArgumentException("长度不是偶数"); byte[] b2 = new byte[b.length / 2]; for (int n = 0; n < b.length; n += 2) { String item = new String(b, n, 2); b2[n / 2] = (byte) Integer.parseInt(item, 16); } return b2; } public static String byte2hex(byte[] b) { String hs = ""; String stmp = ""; for (int n = 0; n < b.length; n++) { stmp = (java.lang.Integer.toHexString(b[n] & 0XFF)); if (stmp.length() == 1) hs = hs + "0" + stmp; else hs = hs + stmp; } return hs.toUpperCase(); }}本文转自：
另一个例子:
[java]
/**
* @author 李国庆
* @company leemenz (C) copyright
* @time Nov 1, 2006 10:18:41 AM
* @version 1.0.0.0
* @package com.des
*/
package com.des;
import java.security.*;
import javax.crypto.*;
public class DESPlus {
private static String strDefaultKey = "national";
private Cipher encryptCipher = null;
private Cipher decryptCipher = null;
/**
* 将byte数组转换为表示16进制值的字符串， 如：byte[]{8,18}转换为：0813， 和public static byte[]
* hexStr2ByteArr(String strIn) 互为可逆的转换过程
*
* @param arrB
* 需要转换的byte数组
* @return 转换后的字符串
* @throws Exception
* 本方法不处理任何异常，所有异常全部抛出
*/