A Lattice-Based Hierarchical Identity Authentication Scheme for Low-Voltage Metering Devices in Power Grids

The identity security of massive metering terminals in low-voltage power distribution systems is a foundational requirement for smart grids. These devices, deployed in physically exposed user-side environ ments, face threats of identity impersonation, data tampering, and future quantum attacks. Conventional public-key certificates and pre-shared key schemes lack quantum resistance and scalability, respectively, while existing post-quantum solutions do not address the combination of hierarchical key management and batch authentication that power metering at scale demands. This paper proposes a lattice-based hierarchical identity authentication method that maps the three-tier power system architecture onto a three-level key derivation chain of hierarchical identity-based signatures, compresses multiple terminal lattice signatures into a compact aggregate verifiable in a single equation, and embeds key agreement into the authentication flow so that terminals and the substation derive independent session keys without extra round trips. A prototype was implemented and tested across multiple security levels. The signature communication volume remained quasi-constant as the terminal count increased, reducing the signature transmission delay on narrowband PLC links. All terminals successfully established independent session keys with exact agreement between both sides. Security reduces to the average-case hardness of the small integer solution problem on lattices, satisfying mutual authentication, conditional anonymity, and unlinkability. The proposed scheme trades higher signing latency for security based on quantum-hard lattice assumptions, group batch authentication, and protocol integration, offering a viable pathway for identity security upgrades in power metering systems during the quantum migration window.