In a method for protecting a calculation in a cryptographic algorithm, the calculation obtaining input data so as to create output data, input data for the calculation are initially provided. The inner and outer faces of the cover are laminated with a plastic film so as to form a double laminated cover. If the data objects do not match, then the storage system performs the storage operation in a usual manner. The reflective device may extend over a substantial majority of a lower surface of the outsole, including a portion of the outer periphery of the outsole.