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; /**  * 密匙工具類(包含des加密與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 根據鍵值進行加密      * @param data       * @param key 加密鍵byte數組      * @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 根據鍵值進行解密      * @param data      * @param key 加密鍵byte數組      * @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 根據鍵值進行加密      * @param data      * @param key 加密鍵byte數組      * @return      * @throws Exception      */     private static byte[] encrypt(byte[] data, byte[] key) throws Exception {       // 生成一個可信任的隨機數源       SecureRandom sr = new SecureRandom();       // 從原始密鑰數據創建DESKeySpec對象       DESKeySpec dks = new DESKeySpec(key);       // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象       SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);       SecretKey securekey = keyFactory.generateSecret(dks);       // Cipher對象實際完成加密操作       Cipher cipher = Cipher.getInstance(DES);       // 用密鑰初始化Cipher對象       cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);       return cipher.doFinal(data);     }     /**     * Description 根據鍵值進行解密     * @param data     * @param key 加密鍵byte數組     * @return     * @throws Exception     */     private static byte[] decrypt(byte[] data, byte[] key) throws Exception {       // 生成一個可信任的隨機數源       SecureRandom sr = new SecureRandom();       // 從原始密鑰數據創建DESKeySpec對象       DESKeySpec dks = new DESKeySpec(key);       // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象       SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);       SecretKey securekey = keyFactory.generateSecret(dks);       // Cipher對象實際完成解密操作       Cipher cipher = Cipher.getInstance(DES);       // 用密鑰初始化Cipher對象       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;   /**    * 將16進制字符串轉換成字節數組    * @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;   }   /**    * 將指定byte數組轉換成16進制字符串    * @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();   }   /**    * 驗證口令是否合法    * @param password    * @param passwordInDb    * @return    * @throws NoSuchAlgorithmException    * @throws UnsupportedEncodingException    */   public static boolean validPassword(String password, String passwordInDb)       throws NoSuchAlgorithmException, UnsupportedEncodingException {     //將16進制字符串格式口令轉換成字節數組     byte[] pwdInDb = hexStringToByte(passwordInDb);     //聲明鹽變量     byte[] salt = new byte[SALT_LENGTH];     //將鹽從數據庫中保存的口令字節數組中提取出來     System.arraycopy(pwdInDb, 0, salt, 0, SALT_LENGTH);     //創建消息摘要對象     MessageDigest md = MessageDigest.getInstance("MD5");     //將鹽數據傳入消息摘要對象     md.update(salt);     //將口令的數據傳給消息摘要對象     md.update(password.getBytes("UTF-8"));     //生成輸入口令的消息摘要     byte[] digest = md.digest();     //聲明一個保存數據庫中口令消息摘要的變量     byte[] digestInDb = new byte[pwdInDb.length - SALT_LENGTH];     //取得數據庫中口令的消息摘要     System.arraycopy(pwdInDb, SALT_LENGTH, digestInDb, 0, digestInDb.length);     //比較根據輸入口令生成的消息摘要和數據庫中消息摘要是否相同     if (Arrays.equals(digest, digestInDb)) {       //口令正確返回口令匹配消息       return true;     } else {       //口令不正確返回口令不匹配消息       return false;     }   }   /**    * 獲得加密后的16進制形式口令    * @param password    * @return    * @throws NoSuchAlgorithmException    * @throws UnsupportedEncodingException    */   public static String getEncryptedPwd(String password)       throws NoSuchAlgorithmException, UnsupportedEncodingException {     //聲明加密后的口令數組變量     byte[] pwd = null;     //隨機數生成器     SecureRandom random = new SecureRandom();     //聲明鹽數組變量     byte[] salt = new byte[SALT_LENGTH];     //將隨機數放入鹽變量中     random.nextBytes(salt);     //聲明消息摘要對象     MessageDigest md = null;     //創建消息摘要     md = MessageDigest.getInstance("MD5");     //將鹽數據傳入消息摘要對象     md.update(salt);     //將口令的數據傳給消息摘要對象     md.update(password.getBytes("UTF-8"));     //獲得消息摘要的字節數組     byte[] digest = md.digest();     //因為要在口令的字節數組中存放鹽，所以加上鹽的字節長度     pwd = new byte[digest.length + SALT_LENGTH];     //將鹽的字節拷貝到生成的加密口令字節數組的前12個字節，以便在驗證口令時取出鹽     System.arraycopy(salt, 0, pwd, 0, SALT_LENGTH);     //將消息摘要拷貝到加密口令字節數組從第13個字節開始的字節     System.arraycopy(digest, 0, pwd, SALT_LENGTH, digest.length);     //將字節數組格式加密后的口令轉化為16進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("歡迎登陸?。?！");       }else{         System.out.println("口令錯誤，請重新輸入！??！");       }     } catch (NoSuchAlgorithmException e) {       // TODO Auto-generated catch block       e.printStackTrace();     } catch (UnsupportedEncodingException e) {       // TODO Auto-generated catch block       e.printStackTrace();     }    }   /**    * 注冊用戶    *    * @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();     }   }   /**    * 驗證登陸    *    * @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){ // 該用戶存在         return MyMD5Util.validPassword(password, pwdInDb);     }else{       System.out.println("不存在該用戶！?。?);       return false;     }   } }