SKM: Scalable Key Management for Advanced Metering Infrastructure in Smart Grids

Advanced metering infrastructure (AMI) plays a critical role in the smart grid. It enables intelligent applications such as load control switching, demand side management, and meter data management by creating a bidirectional communication network for smart meters and utility systems. Consequently, AMI should be strictly protected to ensure reliable and secure operations of smart grid. In this paper, we first show that a recently proposed key management scheme for AMI by Liu et al. suffers from the desynchronization attack, and, at the same time, it lacks scalability due to inefficient key management. Then, we propose a new scalable key management (SKM) scheme characterized by combining identity-based cryptosystem and efficient key tree technique. The scheme SKM possesses advantages of efficiency and flexibility in key management. In particular, the cost of SKM is O(log n) in either aspect of computation and communication (n is the number of smart meters), which is significantly reduced from the cost of O(n) in the scheme of Liu et al. We analyze security and performance of SKM in detail to show that SKM is efficient in computation and communication cost.