Patent ID: 7532104

Claim:
A method for use in an RFID system comprising at least one RFID device and at least one reader which communicates with the RFID device, the method comprising the steps of: associating a plurality of pseudonyms with the RFID device; and transmitting from the RFID device different ones of the pseudonyms in response to different reader queries of the RFID device; wherein an authorized verifier is able to determine that the different transmitted pseudonyms are associated with the same RFID device; wherein the verifier authenticates itself to the RFID device by releasing to the RFID device an authentication value β i unique to a given pseudonym α i transmitted by the RFID device; wherein the RFID device authenticates itself to the verifier by releasing to the verifier an authentication value γ i unique to the given pseudonym α i transmitted by the RFID device; and wherein at least one of the values α i , β i and γ i is selected from a corresponding set of such values that is stored in the RFID device and updated using one-time pads transmitted by the verifier to the RFID device over multiple authentication sessions carried out between the verifier and the RFID device.