Vssdb: A Verifiable Secret-Sharing Distance-Bounding Protocol

International audienceTerrorist fraud is a class of relay attacks against distance-bounding (DB) protocols in which a distant malicious prover colludes with an attacker located in a verifier's proximity when authenticating. Existing DB protocols resisting such attacks are designed to be lightweight and thus symmetric, relying on a secret shared by the prover and the verifier. Recently, several asymmetric distance-bounding protocols were proposed by Gambs, Onete and Robert as well as by Hermans, Peter and Onete, but they fail to thwart terrorist fraud. One earlier asym-metric protocol aiming to be terrorist-fraud resistant is the DBPK-Log protocol due to Bussard and Bagga, which was unfortunately recently proven to achieve neither distance-nor terrorist-fraud resistance. In this work, we build on some ideas of the DBPK-Log scheme and propose a novel DB protocol resistant to terrorist fraud that does not require the pre-existence of a shared secret between the prover and the verifier. Our construction, denoted as Vssdb (for Verifiable Secret Sharing and Distance-Bounding Protocol) relies on a verifiable secret sharing scheme and on the concept of modes, which we introduce as a novel element to complement fast-round challenges in order to improve security. We prove that Vssdb resists mafia-, distance-, and terrorist fraud, as well as impersonation attacks