A card for identifying a user to a computer system using a sensing device, the card having an interface surface having disposed thereon or therein coded data, the coded data including a plurality of coded data portions, each coded data portion being indicative of an identity of the user, the sensing device being adapted to: (a) sense at least one coded data portion; (b) generate, using the at least one sensed coded data portion, indicating data indicative of the identity of the user; and, (c) transfer the indicating data to the computer system, the computer system being responsive to determine, using the indicating data, the identity of the user.