The power grid is currently undergoing changes towards highly volatile and localized energy production and storage, supported by IT and communication components. Smart Metering is going to provide fine-grained measurement and automatic remote reading of consumption and production amounts. It enables flexible tariffing and dynamic load optimization, ultimately aiming at cost and consumption reduction. The related security requirements are mainly authenticity, integrity, and privacy of metering data. Even more challenging is grid automation, which is critical for the safety and availability of the grid.