Protection of consumer data in the smart grid compliant with the German smart metering guideline

Smart metering systems obtain fine-grained consumption data of their users. This allows for effective load balancing, but at the same time threatens consumers' privacy. Since the electricity provider only needs the characteristics of a region, not individuals, approaches like one by Mármol et al. suggest to aggregate data to protect consumer privacy. However, an implementation of such an approach also has to consider the legal and regulatory situation. In Germany, the technical guideline TR-03109 issued by the Federal Office for Information Security specifies demands which have to be fulfilled so that a smart meter gateway can be certified for use. These specifications imply limitations to the protocol design. Within this paper, we discuss the applicability of the method presented by Mármol et al. under consideration of the German Smart Metering guideline. Where conformity is not given, we offer a solution to overcome these restrictions by adapting their method and introduce a third party aggregator who does not have to be trusted. Our method comes with additional communication effort but behaves well in terms of memory and computational overhead. The achieved privacy level outreaches a purely pseudonymous value transmission. Also it does not contradict the postulations of TR-03109, making it an applicable choice for privacy protection in real-world smart metering systems.