A. Mitrokotsa, C. Onete, E. Pagnin , M. Perera Cryptology eprint archive
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Several access control systems are based on the users’ physical location/proximity to the access point. Distance- Bounding (DB) protocols constitute a classical solution to calculate the distance between a trusted verifier (e.g., an access point) and an untrusted prover (e.g., a pervasive device). The main limitation of DB is that the prover and the verifier need to lie in each other’s communication range. In this paper, we introduce the concept of Multi-Hop Distance-Estimation (MHDE) protocols, which enable a verifier to authenticate a possibly far-away prover and estimate its distance to this prover, when they are not in the communication range of each other, using an ad-hoc network of pervasive devices. More precisely, our contributions are three-fold, since we provide: (1) a formal definition for MHDE; (2) a threat model for MHDE that considers a powerful and distributed adversary; and (3) implementation of MHDE protocols with different settings. Additionally, we demonstrate our protocol to be secure in the considered threat model, and we provide a performance analysis regarding the accuracy of the distance estimation and the tolerance of limited mobility of the nodes. The results are promising in order to adopt MHDE in a distributed setting.