LB3AS: Lightweight Blockchain-Assisted Anonymous Authentication Scheme for Fog-Cloud-Based Internet of Medical Things

The flourishing development of the Internet of Medical Things (IoMT) is bringing personalized and timely healthcare to an increasing number of people. Fog-cloud-based IoMT pushes computing and data processing to the edge network, enabling low latency and real-time response. However, the heterogeneity of IoMT and medical data privacy make designing secure and efficient authentication schemes a highly challenging task. In this article, we first design a blockchain-assisted fog-cloud-based IoMT authentication architecture, leveraging blockchain technology to enhance the security and efficiency of medical data sharing. Additionally, we propose a novel anonymous authentication scheme that utilizes lightweight cryptographic primitives, physically unclonable functions, and fuzzy extractors suitable for resource-constrained IoMT devices. We use formal and informal security analysis to prove the security of the proposed scheme. Furthermore, we evaluate the performance of the proposed scheme from the perspectives of computation, communication, energy, average delay time, and smart contract resource consumption. Compared to five related schemes, our scheme achieves higher security while maintaining low resource consumption.