A PUF-Based Mutual Authentication Protocol for Trustless Fog Computing Environments

Fog computing extends cloud capabilities to the edge of the network, addressing the latency and bandwidth issues inherent in the management of Internet of Things (IoT) devices. Yet, this extension introduces new security challenges, particularly in the authentication of endpoints and fog nodes that are susceptible to physical attacks. Physical Unclonable Functions (PUFs) are pivotal for enabling lightweight, energy-efficient, and secure authentication of resource-constrained devices in traditional IoT networks. However, existing PUF-based authentication protocols, which rely on external trusted third parties or the storage of Challenge-Response Pairs (CRPs) within the verifier, are incompatible with the fog computing setting. To address this problem, this paper proposes a PUF-based authentication scheme that requires no storage of CRPs and is well-suited for trustless fog computing environments, achieving mutual authentication and key exchange between devices and fog nodes without the need for a trusted proxy server. The protocol incorporates a dynamic secret parameter update mechanism to ensure Perfect Forward Secrecy (PFS), offering a more convenient and lightweight alternative compared to traditional solutions based on periodic re-registration or elliptic curve multiplication. We formally prove the security of the protocol using the Real-OrRandom (ROR) model and provide a comparative analysis of its performance, demonstrating its superiority in terms of security features, computational efficiency, and communication cost.