A Terrorist-fraud Resistant and Extractor-free Anonymous Distance-bounding Protocol

International audienceDistance-bounding protocols have been introduced to thwart relay attacks against contactless authentication protocols. In this context, veri-fiers have to authenticate the credentials of untrusted provers. Unfortunately , these protocols are themselves subject to complex threats such as terrorist-fraud attacks, in which a malicious prover helps an accomplice to authenticate. Provably guaranteeing the resistance of distance-bounding protocols to these attacks is a complex task. The classical countermeasures usually assume that rational provers want to protect their long-term authentication credentials, even with respect to their accomplices. Thus, terrorist-fraud resistant protocols generally rely on artificial extraction mechanisms, ensuring that an accomplice can retrieve the credential of his partnering prover. In this paper, we propose a novel approach to obtain provable terrorist-fraud resistant protocols without assuming that provers have any long-term secret key. Instead, the attacker simply has to replay the information that he has received from his accomplice. Based on this, we present a generic construction for provably secure distance-bounding protocols, and give three instances: (1) an efficient symmetric-key protocol, (2) a public-key protocol protecting the identities of the provers against external eavesdroppers, and finally (3) a fully anonymous protocol protecting the identities of the provers even against malicious verifiers trying to profile them