PrETP: privacy-preserving electronic toll pricing

Abstract

Current Electronic Toll Pricing (ETP) implementations rely on on-board units sending fine-grained location data to the service provider. We present PrETP, a privacy-preserving ETP system in which on-board units can prove that they use genuine data and perform correct operations while disclosing the minimum amount of location data. PrETP employs a cryptographic protocol, Optimistic Payment, which we define in the idealworld/real-world paradigm, construct, and prove secure under standard assumptions. We provide an efficient implementation of this construction and build an on-board unit on an embedded microcontroller which is, to the best of our knowledge, the first self-contained prototype that supports remote auditing. We thoroughly analyze our system from a security, legal and performance perspective and demonstrate that PrETP is suitable for low-cost commercial applications. 1