Distance-bounding for RFID: Effectiveness of ‘terrorist fraud’ in the presence of bit errors

Abstract

Time-of-flight distance-bounding protocols are potentially useful in RFID and NFC environments and are designed to discourage a number of attacks that take advantage of the inherent assumption that a token and reader that manages to communicate are located in close physical proximity to each other. These protocols are dependent on time measurements made at the physical layer of the communication channel, and thus require special high bandwidth channels with low latency. Executing a distance-bound protocol on a suitable channel in a constrained environment would potentially allow for bit errors during communication. Currently, terrorist fraud is discouraged in distance-bounding protocols by ensuring that a prover collaborating with an the attacker in this fraud has to make his secret key known to the attacker. We discuss the effect of making a protocol resistant to bit errors and show that the approach to design protocols against terrorist fraud is significantly weakened by error resistance, as a prover is potentially able to keep his key secret or hinder an attacker from learning his key.