Key Establishment Using Secure Distance Bounding Protocols

Key establishment is one of the major challenges in wireless personal area networks, as traditional security mechanisms often do not cope with the dynamic characteristics of wireless ad-hoc networks. In this paper, we present an efficient key establishment protocol, based on the basic Diffie-Hellman protocol. It enables mutual device authentication through presence and establishes a session key between personal mobile devices which do not yet share any authenticated cryptographic material. Distance bounding protocols, which have been introduced by Brands and Chaum at Eurocrypt´93 to preclude distance fraud and mafia fraud attacks, are employed to determine an upper- bound on the distance to another entity. Our solution only requires limited user-interaction: the user of a mobile device is expected to perform a visual verification within a small physical space.