Java实现DES加密与解密，md5加密以及Java实现MD5加密解密类

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);
     }
 }

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); 
  } 
} 

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; 
    } 
  } 
}