PRAC: Efficient privacy protection for vehicle-to-grid communications in the smart grid

In expectation of extensive usage of electric vehicles (EVs) in the near future, vehicle-to-grid (V2G) system is envisioned to be a key component of the smart grid, and it has demonstrated great potential in providing valuable ancillary services such as load balancing, regulation, and reserves. The success of a V2G system largely depends on a credible incentive scheme to motivate a huge number of EVs to participate, but the side effect is that EVs in V2G may suffer from privacy risks concerning their whereabouts. So far little has been done to address the privacy threat, and existent work is inefficient in computation and communication and/or provides defective protection. In this paper, we propose a privacy-preserving solution for V2G communications known as PRAC (Privacy via Randomized Anonymous Credentials). As a full-fledged security protocol suite, PRAC features not only anonymity and untraceability for EVs in authentication as well as service rewarding, but also rewarding fairness and non-repudiation. Thorough analysis reveals that PRAC is secure and is also cost-effective. Compared with the V2G literature, this paper features a prototype implemented on commodity hardware and free software. Extensive experiments demonstrate that PRAC is likely to be a promising solution for any modern electric vehicle.