A Key Management Scheme for Secure Communications of Advanced Metering Infrastructure in Smart Grid

Advanced metering infrastructure (AMI) is an important component of the smart grid. The cyber security should be considered prior to the AMI system applications. To ensure confidentiality and integrality, a key management scheme (KMS) for a large amount of smart meters (SMs) and devices is required, which is not a properly solved problem until now. Compared with other systems, there are three specific features of AMI that should be carefully considered, including hybrid transmission modes of messages, storage and computation constraints of SMs, and unfixed participators in demand response (DR) projects. In order to deal with security requirements and considering the distinctive features, a novel KMS is proposed. First, the key management framework of an AMI system is constructed based on the key graph. Furthermore, three different key management processes are designed to deal with the hybrid transmission modes, including key management for unicast, broadcast, and multicast modes. Relatively simple cryptographic algorithms are chosen for key generation and refreshing policies due to the storage and computation constraints of SMs. Specific key refreshing policies are designed since the participators in a certain DR project are not fixed. Finally, the security and performance of the KMS are analyzed. According to the results, the proposed scheme is a possible solution for AMI systems.