Traditional electricity meters are replaced by Smart Meters in customers' households. Smart Meters collects fine-grained utility consumption profiles from customers, which in turn enables the introduction of dynamic, time-of-use tariffs. However, the fine-grained usage data that is compiled in this process also allows to infer the inhabitant's personal schedules and habits. We propose a privacy-preserving protocol that enables billing with time-of-use tariffs without disclosing the actual 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 system. We require no changes to the Smart Meter hardware and only small changes to the software of Smart Meter and back-end system. In this paper we describe the functional and privacy requirements, the specification and security proof of our solution and give a performance evaluation of a prototypical implementation.
The smart grid is seen as the greatest technological invention — in the context of energy supply — since the grid connection of millions of households. Smart metering, as the enabling technology for the future grid, attracts attention of industry, politics, and the scientific community. As smart meters are spreading into more and more households, electricity customers are directly affected by the technology. At the same time, critical voices accuse smart metering of violating customers’ privacy. Personal data are collected, allowing electricity service providers a monitoring of customers’ habits. In this paper, we propose a solution that provides anonymity for customers towards their ESP. At the same time, we do not limit the functionality that the ESP is asking for, especially the periodic reporting of customers’ current electricity consumption values. Moreover, our concept allows for the ESP to build trust in the software that is executed within their customers’ smart meters.