Java实现DES加密与解密，md5加密以及Java实现MD5加密解密类

很多时候要对秘要进行持久化加密，此时的加密采用md5。采用对称加密的时候就采用DES方法了

import java.io.IOException;
  import java.security.MessageDigest;
  import java.security.SecureRandom;
  import javax.crypto.Cipher;
  import javax.crypto.SecretKey;
  import javax.crypto.SecretKeyFactory;
  import javax.crypto.spec.DESKeySpec;
 import sun.misc.BASEDecoder;
 import sun.misc.BASEEncoder;
 /**
  * 密匙工具类(包含des加密与md加密)
  * @author mingge
  *
  */
 public class KeysUtil {
     private final static String DES = "DES";
     private final static String MD = "MD";
     private final static String KEY="opeddsaeaddadbcabf";
     /**
      * MD加密算法
      * @param data
      * @return
      */
     public static String mdEncrypt(String data) {
       String resultString = null;
       try {
         resultString = new String(data);
         MessageDigest md = MessageDigest.getInstance(MD);
         resultString =bytehexString(md.digest(resultString.getBytes()));
       } catch (Exception ex) {
       }
       return resultString;
     }
     private static String bytehexString(byte[] bytes) {
       StringBuffer bf = new StringBuffer(bytes.length * );
       for (int i = ; i < bytes.length; i++) {
         if ((bytes[i] & xff) < x) {
           bf.append("T");
         }
         bf.append(Long.toString(bytes[i] & xff, ));
       }
       return bf.toString();
     }
     /**
      * Description 根据键值进行加密
      * @param data
      * @param key 加密键byte数组
      * @return
      * @throws Exception
      */
     public static String desEncrypt(String data, String key) throws Exception {
       if (key==null) {
         key=KEY;
       }
       byte[] bt = encrypt(data.getBytes(), key.getBytes());
       String strs = new BASEEncoder().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 desDecrypt(String data, String key) throws IOException,
         Exception {
       if (data == null){
         return null;
       }
       if (key==null) {
         key=KEY;
       }
       BASEDecoder decoder = new BASEDecoder();
       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 static byte[] encrypt(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);
     }
 }

下面在给大家介绍一段代码关于Java实现MD5加密解密类

Java实现MD5加密以及解密类，附带测试类，具体见代码。

MD5加密解密类——MyMD5Util,代码如下：

package com.zyg.security.md5;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
public class MyMD5Util {
  private static final String HEX_NUMS_STR="0123456789ABCDEF";
  private static final Integer SALT_LENGTH = 12;
  /**
   * 将16进制字符串转换成字节数组
   * @param hex
   * @return
   */
  public static byte[] hexStringToByte(String hex) {
    int len = (hex.length() / 2);
    byte[] result = new byte[len];
    char[] hexChars = hex.toCharArray();
    for (int i = 0; i < len; i++) {
      int pos = i * 2;
      result[i] = (byte) (HEX_NUMS_STR.indexOf(hexChars[pos]) << 4
              | HEX_NUMS_STR.indexOf(hexChars[pos + 1]));
    }
    return result;
  }
  /**
   * 将指定byte数组转换成16进制字符串
   * @param b
   * @return
   */
  public static String byteToHexString(byte[] b) {
    StringBuffer hexString = new StringBuffer();
    for (int i = 0; i < b.length; i++) {
      String hex = Integer.toHexString(b[i] & 0xFF);
      if (hex.length() == 1) {
        hex = '0' + hex;
      }
      hexString.append(hex.toUpperCase());
    }
    return hexString.toString();
  }
  /**
   * 验证口令是否合法
   * @param password
   * @param passwordInDb
   * @return
   * @throws NoSuchAlgorithmException
   * @throws UnsupportedEncodingException
   */
  public static boolean validPassword(String password, String passwordInDb)
      throws NoSuchAlgorithmException, UnsupportedEncodingException {
    //将16进制字符串格式口令转换成字节数组
    byte[] pwdInDb = hexStringToByte(passwordInDb);
    //声明盐变量
    byte[] salt = new byte[SALT_LENGTH];
    //将盐从数据库中保存的口令字节数组中提取出来
    System.arraycopy(pwdInDb, 0, salt, 0, SALT_LENGTH);
    //创建消息摘要对象
    MessageDigest md = MessageDigest.getInstance("MD5");
    //将盐数据传入消息摘要对象
    md.update(salt);
    //将口令的数据传给消息摘要对象
    md.update(password.getBytes("UTF-8"));
    //生成输入口令的消息摘要
    byte[] digest = md.digest();
    //声明一个保存数据库中口令消息摘要的变量
    byte[] digestInDb = new byte[pwdInDb.length - SALT_LENGTH];
    //取得数据库中口令的消息摘要
    System.arraycopy(pwdInDb, SALT_LENGTH, digestInDb, 0, digestInDb.length);
    //比较根据输入口令生成的消息摘要和数据库中消息摘要是否相同
    if (Arrays.equals(digest, digestInDb)) {
      //口令正确返回口令匹配消息
      return true;
    } else {
      //口令不正确返回口令不匹配消息
      return false;
    }
  }
  /**
   * 获得加密后的16进制形式口令
   * @param password
   * @return
   * @throws NoSuchAlgorithmException
   * @throws UnsupportedEncodingException
   */
  public static String getEncryptedPwd(String password)
      throws NoSuchAlgorithmException, UnsupportedEncodingException {
    //声明加密后的口令数组变量
    byte[] pwd = null;
    //随机数生成器
    SecureRandom random = new SecureRandom();
    //声明盐数组变量
    byte[] salt = new byte[SALT_LENGTH];
    //将随机数放入盐变量中
    random.nextBytes(salt);
    //声明消息摘要对象
    MessageDigest md = null;
    //创建消息摘要
    md = MessageDigest.getInstance("MD5");
    //将盐数据传入消息摘要对象
    md.update(salt);
    //将口令的数据传给消息摘要对象
    md.update(password.getBytes("UTF-8"));
    //获得消息摘要的字节数组
    byte[] digest = md.digest();
    //因为要在口令的字节数组中存放盐，所以加上盐的字节长度
    pwd = new byte[digest.length + SALT_LENGTH];
    //将盐的字节拷贝到生成的加密口令字节数组的前12个字节，以便在验证口令时取出盐
    System.arraycopy(salt, 0, pwd, 0, SALT_LENGTH);
    //将消息摘要拷贝到加密口令字节数组从第13个字节开始的字节
    System.arraycopy(digest, 0, pwd, SALT_LENGTH, digest.length);
    //将字节数组格式加密后的口令转化为16进制字符串格式的口令
    return byteToHexString(pwd);
  }
} 

测试类——Client,代码如下：

package com.zyg.security.md5;
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;
public class Client {
  private static Map users = new HashMap();
  public static void main(String[] args){
    String userName = "zyg";
    String password = "123";
    registerUser(userName,password);
    userName = "changong";
    password = "456";
    registerUser(userName,password);
    String loginUserId = "zyg";
    String pwd = "1232";
    try {
      if(loginValid(loginUserId,pwd)){
        System.out.println("欢迎登陆！！！");
      }else{
        System.out.println("口令错误，请重新输入！！！");
      }
    } catch (NoSuchAlgorithmException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  /**
   * 注册用户
   *
   * @param userName
   * @param password
   */
  public static void registerUser(String userName,String password){
    String encryptedPwd = null;
    try {
      encryptedPwd = MyMD5Util.getEncryptedPwd(password);
      users.put(userName, encryptedPwd);
    } catch (NoSuchAlgorithmException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  /**
   * 验证登陆
   *
   * @param userName
   * @param password
   * @return
   * @throws UnsupportedEncodingException
   * @throws NoSuchAlgorithmException
   */
  public static boolean loginValid(String userName,String password)
        throws NoSuchAlgorithmException, UnsupportedEncodingException{
    String pwdInDb = (String)users.get(userName);
    if(null!=pwdInDb){ // 该用户存在
        return MyMD5Util.validPassword(password, pwdInDb);
    }else{
      System.out.println("不存在该用户！！！");
      return false;
    }
  }
}