DES算法简介    

DES（Data Encryption Standard）是发明最早的最广泛使用的分组对称加密算法。DES算法的入口参数有三个：Key、Data、Mode。其中Key为8个字节共64位，是DES算法的工作密钥；Data也为8个字节64位，是要被加密或被解密的数据；Mode为DES的工作方式，有两种：加密或解密。

import java.io.IOException;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.SecretKey;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESKeySpec;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder; public class CodeEode {      private final static String DES = "DES";    private static CodeEode codeEode = null;    private String key="wanghejia.com";    public CodeEode(String key) {         this.key=key;    }    /**     *      * @param key     * @return     */    public static CodeEode getInstance(String key) {         if ((codeEode == null) && (!key.isEmpty())) {             return new CodeEode(key);        }        return codeEode;    }    public static CodeEode getInstance() {         if (codeEode == null) {             return new CodeEode("wanghejia.com");        }        return codeEode;    }    /**     * Description 根据键值进行加密     * @param data      * @param key  加密键byte数组     * @return     * @throws Exception     */    public  String encrypt(String data) throws Exception {         byte[] bt = encrypt(data.getBytes());        String strs = new BASE64Encoder().encode(bt);        return strs;    }     /**     * Description 根据键值进行解密     * @param data     * @param key  加密键byte数组     * @return     * @throws IOException     * @throws Exception     */    public static String decrypt(String data, String key) throws IOException,            Exception {         if (data == null)            return null;        BASE64Decoder decoder = new BASE64Decoder();        byte[] buf = decoder.decodeBuffer(data);        byte[] bt = decrypt(buf,key.getBytes());        return new String(bt);    }     /**     * Description 根据键值进行加密     * @param data     * @param key  加密键byte数组     * @return     * @throws Exception     */    private  byte[] encrypt(byte[] data) throws Exception {         // 生成一个可信任的随机数源        SecureRandom sr = new SecureRandom();         // 从原始密钥数据创建DESKeySpec对象        byte[] keys=this.key.getBytes();        DESKeySpec dks = new DESKeySpec(keys);         // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);        SecretKey securekey = keyFactory.generateSecret(dks);         // Cipher对象实际完成加密操作        Cipher cipher = Cipher.getInstance(DES);         // 用密钥初始化Cipher对象        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);         return cipher.doFinal(data);    }              /**     * Description 根据键值进行解密     * @param data     * @param key  加密键byte数组     * @return     * @throws Exception     */    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {         // 生成一个可信任的随机数源        SecureRandom sr = new SecureRandom();         // 从原始密钥数据创建DESKeySpec对象        DESKeySpec dks = new DESKeySpec(key);         // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);        SecretKey securekey = keyFactory.generateSecret(dks);         // Cipher对象实际完成解密操作        Cipher cipher = Cipher.getInstance(DES);         // 用密钥初始化Cipher对象        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);         return cipher.doFinal(data);    }    public static void main(String[] args) throws Exception {         System.out.println(CodeEode.getInstance().encrypt("123456"));    }}