Balanced ternary-key tree based dynamic key management for smart meter groups

The development of new power systems and large-scale deployment of smart metering devices have driven strong demand for group applications such as localized flexible load control and coordinated low-voltage distribution management. These applications require secure and efficient group management for devices with similar electrical and operational characteristics. However, traditional point-to-point encryption is unsuitable for group scenarios, and existing group encryption schemes suffer from low efficiency and poor forward/backward secrecy under frequent dynamic membership changes, which threatens the security and stability of smart metering systems. To address these problems, this paper proposes a dynamic key management scheme based on a balanced ternary-key tree (BTKT) for smart meter groups. A dedicated system architecture is designed, and an efficient group key update mechanism is introduced. Security and performance are verified through experiments on a regional network with 750 devices. The results show that the proposed scheme guarantees secure key updates, achieves reliable forward and backward secrecy under dynamic membership, and exhibits better efficiency than conventional schemes. This approach provides an effective and practical solution for secure group communication in smart metering systems, supporting the reliable operation of group applications in new power systems. • Propose a ternary-key tree based dynamic key management method with an exclusive architecture for smart meters. • Solve traditional encryption inefficiency in groups, ensuring key update and forward/backward security. • Ternary-key tree structure is stable, cutting key construction/update time and traffic by 97.19%, 97.57%, 92.82%. • Reduce storage demand: gateway and smart meter key storage down by 91.65% and 87.50%. • Verify the method’s security and efficiency via a 750-device regional network.