Abstract
A distance bounding protocol provides an upper bound on the distance between communicating parties by measuring the round-trip time between challenges and responses. It is an effective countermeasure against mafia fraud attacks (a.k.a. relay attacks). The adversary success probability of previous distance bounding protocols without a final confirmation message such as digital signature or message authentication code is at least $\left(\frac{3}{8}\right)^n = \left(\frac{1}{2.67}\right)^n$. We propose a unilateral distance bounding protocol without a final confirmation message, which reduces the adversary success probability to $\left(\frac{5}{16}\right)^n = \left(\frac{1}{3.2}\right)^n$.
