BPAF: Blockchain-Enabled Reliable and Privacy-Preserving Authentication for Fog-Based IoT Devices

The development of IoT and fog computing promotes various kinds of authentication mechanisms for IoT devices. Traditional IoT authentication schemes are based on Public Key Infrastructure (PKI) where a centralized certificate authority is introduced. To mitigate the security, privacy, and reliability issues bring from the centralization, some blockchain-based authentication schemes have been presented to achieve decentralized authentication. Unfortunately, they cannot be directly used under the fog-based IoT environment, which consists of resource-constrained IoT devices. To mitigate these issues, we present a Blockchain-enabled reliable, and Privacy-preserving Authentication for Fog-based IoT devices, named BPAF. BPAF achieves reliable authentication of fog nodes without violating the privacy of authenticated users during the authentication process. Security analysis and experimental evaluations show that BPAF achieves privacy-preserving and reliable authentication with high efficiency for both the fog nodes and full nodes participating in the authentication process.