the present invention discloses a usb memory card such as an intelligent stick , of which a control of data encryption is included to enhance data security and meet the data security requirement . the usb memory card of this invention is applicable for the traditional smart card market , like as e - commerce , id token in internet , as well as featuring a low system cost and a popular usb interface . the size of such usb memory card is small , easy - to - carry , and easy - to - use .