javaMD5、DES加密解密

有几天没有写博客了，今天闲着无聊，看了一下java中的加密、解密，主要是MD5和DES加密和解密，特意做成了一个工具类，方便需要的时候拿来使用，在项目中比如用户的密码比较隐私的信息可以采用MD5加密，像Cookie之类的可以采用DES加密，毕竟到服务端来的时候，你还要把信息解析出来！

package com.taobao.frame.utils;

import java.security.MessageDigest;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.SecretKeySpec;

public class CodeUtil {

    private static final String PASSWORD_CRYPT_KEY = "hechangchun";
    private final static String DES = "DES";

    /**
     * MD5加密 32位
     */
    public static String MD5Reversible(String inStr) {
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }
        char[] charArray = inStr.toCharArray();
        byte[] byteArray = new byte[charArray.length];
        for (int i = 0; i < charArray.length; i++)
            byteArray[i] = (byte) charArray[i];
        byte[] md5Bytes = md5.digest(byteArray);
        StringBuffer hexValue = new StringBuffer();
        for (int i = 0; i < md5Bytes.length; i++) {
            int val = ((int) md5Bytes[i]) & 0xff;
            if (val < 16)
                hexValue.append("0");
            hexValue.append(Integer.toHexString(val));
        }
        return hexValue.toString();
    }
    /**
     * 加密 
     */
    public static byte[] encrypt(byte[] src, 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(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 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(src);
    }

    /**
     * 解密
     */
    public static byte[] decrypt(byte[] src, 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(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 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(src);
    }

    /**
     * 密码解密
     */
    public final static String decrypt(String data) {
        try {
            return new String(decrypt(hex2byte(data.getBytes()),PASSWORD_CRYPT_KEY.getBytes()));
        } catch (Exception e) {
        }
        return null;
    }

    /**
     * 密码加密 
     */
    public final static String encrypt(String password) {
        try {
            return byte2hex(encrypt(password.getBytes(), PASSWORD_CRYPT_KEY.getBytes()));
        } catch (Exception e) {
        }
        return null;
    }
    /**
     * 二行制转字符串
     */
    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();
    }

    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;
    }
    
    /**
     * HMAC加密
     */
    public static byte[] encryptHMAC(byte[] data, byte[] key) throws Exception  {
        SecretKey secretKey = new SecretKeySpec(key, "HmacMD5");
        Mac mac = Mac.getInstance(secretKey.getAlgorithm());
        mac.init(secretKey);
        return mac.doFinal(data);

    }
    /**
     * HMAC签名
     */
    public static String sign(String sb,String secret){
        try{
            return byte2hex(encryptHMAC(sb.toString().getBytes("utf-8"), secret.getBytes("utf-8")));
        }
        catch(Exception e){
            return null;
        }
    }
}