Plug-in privacy for Smart Metering billing

Smart Metering is a concept that allows to collect fine-grained consumption profiles from customers by replacing traditional electricity meters with Smart Meters in customers' households. The recorded consumption profile is the basis for the calculation of time-dependent tariffs but also allows deduction of the inhabitant's personal schedules and habits. The current reporting of such consumption profiles only protects this data from 3rd parties but falls short to protect the customer's privacy from illegitimate abuse by the supplier itself. We propose a privacy-preserving profile reporting protocol that enables billing for time-dependent tariffs without disclosing the actual data of the consumption profile to the supplier. Our approach relies on a zero-knowledge proof based on Pedersen Commitments performed by a plug-in privacy component that is put into the communication link between Smart Meter and supplier's back-end systems and requires no change to Smart Meter hardware and only little change to the software of Smart Meter and back-end systems. In this paper we describe the general requirement for a solution, the specification and proof for our solution and a performance evaluation of a prototypical implementation.