An anonymous and unlinkable electronic toll collection system

Electronic toll collection (ETC) systems make it easier for drivers to pay the fee for driving on toll roads. Nevertheless, digitalization of any process enables the service provider to collect digital records containing an accurate description of all the transactions carried out by users. This is the case for ETC systems. Moreover, records about road usage contain data about people’s driving habits, from which highly sensitive personal information can be inferred. Hence, these systems should be designed in such a way that the privacy of drivers is preserved. In this paper we present an ETC system which guarantees that drivers pay the amount corresponding to their journeys while preserving their privacy in the sense that all the interactions of a car with the system are anonymous and unlinkable. To the best of our knowledge, this is the first ETC proposal in which the system server is unable to link the entrance and exit points of a trip. The security of the proposal has been analyzed, while its performance has been tested from a prototype implementation which proves its feasibility.