RFID Distance Bounding Protocols

Almost all existing RFID tag/reader authentication protocols are vulnerable to mafia attacks and/or terrorist attacks from adversaries because of their inability to verify location of the tag. Several protocols have been proposed that purport to alleviate these forms of attacks. However, vulnerabilities have been identified in most of these protocols. The authors present and evaluate a modified distance bounding protocol. Relay attack occurs when a valid reader (or, tag) is tricked by an adversary into believing that it is communicating with a valid tag (or, reader). These attacks are especially difficult to prevent because the adversary generally does not alter signals between tag and reader.