The accessory is capable of connecting to a host device, which is physically separated from the accessory. The accessory includes a first communication module and a contactless module. The first communication module is used to wirelessly coupled to the host device, and receive a first credential from the host device. The contactless module is coupled to the first communication module. The contactless module includes a controller, a first security element, an antenna, and a storage unit. The controller receives the credential from the first communication module. The first security element is coupled to the controller for receiving and storing the first credential. The antenna is coupled to the controller to wirelessly communicate with a first reader for a first application by using the stored first credential. The storage unit stores at least one first transaction record generated during the first application is operating.