Provable Secure Group Key Establishment Scheme for Fog Computing

In the fog computing paradigms, fog nodes are closer to terminal devices and can extend services to the edge of the network, thereby reducing the impact of high latency and restricted networks in the Internet of Things (IoTs). Fog computing applications usually organize the terminal devices in groups and require some form of security protection. Previous studies on the establishment of group keys for fog computing architectures have high communication costs and cannot verify the authenticity of each entity. Therefore, in this paper, we propose a mutual authentication group key establishment scheme for the fog computing architecture by using elliptic curve cryptography. After mutual authentication, the cloud server can transfer the computing overhead to the fog node, which will be responsible for authenticating the device group and distributing the established group session key. The group session key consists of the private key of each entity and some random and temporarily stored values. We prove that the established group session key is protected by the Canetti-Krawczyk (CK) adversary model. Finally, we evaluate performance based on calculation and communication costs. Compared with previous studies, the proposed scheme is lightweight and effective because it only involves elliptic curve operations and symmetric cryptographic operations.