A secure blockchain-based group key agreement protocol for IoT

Since most Internet of things (IoT) devices are energy-limited, increasingly more manufacturers have chosen to develop IoT applications based on group communication. For these applications, a secure and effective authenticated group secret key is fundamental to whole group communication. A large number of related protocols have been proposed to address this security problem. However, most of them have a centralized architecture, which is vulnerable to a single point of failure. Blockchain technology has the potential to address the challenges mentioned above because of its distributed, secure, and private property. Thus, this paper proposes a blockchainbased authenticated group key agreement protocol for IoT. The proposed protocol introduces a new entity called the device manager, who acts as an intermediary to connect IoT devices with blockchain networks. Security analysis demonstrates the robustness of the proposed protocol to various kinds of attacks. Besides, the simulation results further show that the time costs of protocol operations are reasonable and suitable for IoT environments.