Privacy-Preserving and Secure Decentralized Access Control System for Low Emission Zones

A Low Emission Zone (LEZ) is an area where certain restrictions are applied to their users in accordance to their vehicle emissions. Recently, these special areas are representing a popular solution to traffic congestion and environmental pollution in large cities. Even though LEZs have proven to be an effective measure against those issues, they have also been criticized in the literature due to the relevant privacy threat that they represent to the drivers passing by. In particular, current deployed systems used to enforce LEZs strongly depend on the use of camera networks that track the drivers’ whereabouts indiscriminately; moreover, they have a strong dependence on centralized entities to manage the processes related to vehicles’ access authorization and fee payment, central entities that, due to their inherent omniscience, obtain a favorable position in front of the users which allows them to jeopardize their privacy. To address those issues, this paper presents an access control system for LEZs that provides effective antifraud measures, preserves the privacy of the honest drivers, and allows the decentralization of those entities responsible of registering vehicle accesses and charging their corresponding fees by means of blockchain technology.