又一種對字串加密的函數

#region  對字串的加密/解密

         ///   <summary>
         ///  對字串進行適應 ServU 的 MD5 加密
         ///   </summary>
         ///   <param name="str"></param>
         ///   <returns></returns>
         public   static   string  strServUPWD( string  str)
        {
             string  strResult  =   "" ;
            strResult  =  Str.RandomSTR( 2 );
            str  =  strResult  +  str;
            str  =  NoneEncrypt(str, 1 );
            str  =  strResult  +  str;

             return  str;
        }

         ///   <summary>
         ///  對字串進行加密（無法復原）
         ///   </summary>
         ///   <param name="Password"> 要加密的字串 </param>
         ///   <param name="Format"> 加密方式,0 is SHA1,1 is MD5 </param>
         ///   <returns></returns>
         public   static   string  NoneEncrypt( string  Password, int  Format)
        {
             string  strResult  =   "" ;
             switch ( Format )
            {
                 case   0     :
                    strResult  =  FormsAuthentication.HashPasswordForStoringInConfigFile(Password, " SHA1 " );
                     break ;
                 case   1     :
                    strResult  =  FormsAuthentication.HashPasswordForStoringInConfigFile(Password, " MD5 " );
                     break ;
                 default     :
                    strResult  =  Password;
                     break ;
            }

             return  strResult;
        }


         ///   <summary>
         ///  對字串進行加密
         ///   </summary>
         ///   <param name="Passowrd"> 待加密的字串 </param>
         ///   <returns> string </returns>
         public   static   string  Encrypt( string  Passowrd)
        {
             string  strResult  =   "" ;

            FormsAuthenticationTicket ticket  =   new  FormsAuthenticationTicket(Passowrd,  true ,  2 );
            strResult  =  FormsAuthentication.Encrypt(ticket).ToString();
            
             return  strResult;
        }


         ///   <summary>
         ///  對字串進行解密
         ///   </summary>
         ///   <param name="Passowrd"> 已加密的字串 </param>
         ///   <returns></returns>
         public   static   string  Decrypt( string  Passowrd)
        {
             string  strResult  =   "" ;

            strResult  =  FormsAuthentication.Decrypt(Passowrd).Name.ToString();
            
             return  strResult;
        }

         #endregion