AMA: Anonymous mutual authentication with traceability in carpooling systems

Carpooling, as an effective and eco-friendly travel mode, becomes a kind of public spontaneous behavior with multiple travellers sharing a vehicle to reduce individuals' travel cost, carbon emissions and traffic congestion. Although ubiquitous network access offers great convenience for travellers to find carpools, the safety becomes a big obstacle for them to accept this emerging travel mode. To address the safety concern, it seems inevitable to sacrifice the identity privacy for both drivers and passengers. In this paper, we propose an Anonymous Mutual Authentication (AMA) protocol to solve the contradiction between safety and privacy preservation by utilizing the BBS+ signature. In AMA, the passenger and the driver can mutually authenticate the identities without exposing their actual identities, but showing their membership of a trustable group. The AMA also allows to trace the identity of the driver (the passenger) on behalf of a judger if the passenger (the driver) complains the misbehavior of the driver (the passenger). The AMA is secure and efficient for real applications.