Semi-Trusted Edge-Node-Assisted Batch Authentication and Key Agreement Scheme for IIoT

In traditional industrial Internet of Things (IIoT) authentication and key agreement (AKA) schemes, users must establish one-to-one authentication with industrial devices via a trusted gateway. This approach results in significant computational and communication overhead in large-scale deployments. Moreover, the reliance on the gateway introduces a single-point-of-failure and places excessive dependence on the security capabilities of the gateway. To address these issues, this paper proposes a semi-trusted edge node-assisted batch AKA scheme for IIoT environments. First, we establish an edge node-assisted IIoT system model, where edge nodes replace gateways in facilitating batch AKA between users and industrial devices, effectively mitigating the single-point-of-failure problem inherent in gateway-based systems. Second, we design an efficient batch AKA mechanism. Entities achieve mutual authentication based on Elliptic Curve Cryptography and the hidden pair secrets issued by the gateway during the registration phase. The edge node employs the Chinese Remainder Theorem and Euler’s Theorem to facilitate the batch distribution of seed keys to multiple devices, thereby assisting in the batch AKA process between users and multiple devices. Finally, our scheme only requires edge nodes to be semi-trusted, eliminating the dependency on gateways during the AKA process, which better aligns with the practical requirements of real-world IIoT environments. Security is demonstrated through the ROR model, heuristic analysis, and verification using the Scyther tool. Performance evaluations show that the proposed scheme achieves low computational and communication overhead while satisfying the desired security functionality, and also exhibits favorable network performance.