Understanding Game-Based Privacy Proofs for Energy Consumption Aggregation Protocols

Despite the large number of privacy-preserving aggregation protocols in the smart grid, there is no common methodology for evaluating and comparing their privacy guarantees. Protocol discussion often lacks a formal evaluation of the proposed privacy guarantees. In order to transfer the wellestablished formal methodology of game-based proofs to the smart grid domain, in this paper we: 1) present a game-based privacy definition which addresses the privacy requirement to be captured in an aggregation protocol (the definition may be used or extended for other protocols); 2) exemplify our game-based proof technique for two aggregation protocols; and 3) provide a novel and compact way to visualize and easily compare the privacy guarantees of different protocols. We employ two sample protocols that reflect the basis of the most common approaches currently found in the energy aggregation literature. In summary, we contribute a guideline on how to conduct formal evaluations for protocol developers as well as an easy-to-understand way to assess the privacy guarantees of different aggregation protocols for non-experts.