Defining Secure Areas for TDOA-Enhanced Non-Ideal Distance Bounding

In this paper, we show that our recently proposed method to enhance distance bounding (DB) by time difference of arrival (TDOA) measurements improves the security of current DB protocols by reducing their uncertainty area (UA). DB protocols are employed such that a verifier node can authenticate a prover node and at the same time ensure that the prover is close enough to the verifier. TDOA-Enhanced DB increases the security of existing DB protocols by the use of passively listening verifiers, that are employed additionally to the DB primary verifier. We verify our proposed method with measurements in a laboratory setup with hardware that is equipped with Qorvo DW1000 Ultra-Wideband transceivers. We also derive the Crámer-Rae Lower Bound for TDOA with different noise sources and compare it with the measurements to calculate the TDOA-Enhanced UA. By performing a TDOA-Enhanced location verification, we show that an UA reduction is possible in 78% of positions in a 20m x 20m square. This significantly reduces the probability of a successful attack at the physical layer of DB protocols.