Criptografia

public static String encrypt(String user, String password) {    
      String sign = user + password;    
  
      try {    
         java.security.MessageDigest md =    
            java.security.MessageDigest.getInstance("MD5");    
         md.update(sign.getBytes());    
         byte[] hash = md.digest();    
         StringBuffer hexString = new StringBuffer();    
         for (int i = 0; i < hash.length; i++) {    
            if ((0xff & hash[i]) < 0x10)    
               hexString.append(    
                  "0" + Integer.toHexString((0xFF & hash[i])));    
            else    
               hexString.append(Integer.toHexString(0xFF & hash[i]));    
         }    
         sign = hexString.toString();    
      }    
      catch (Exception nsae) {    
         nsae.printStackTrace();    
      }    
      return sign;    
   }