Toward Secure and Efficient Collaborative Cached Data Auditing for Distributed Fog Computing

Fog computing is one of the promising models for mobile edge computing, and greatly reduces the latency of applications by establishing a distributed fog caching system on IoT devices. However, with the popularity and application of fog computing, there are growing concerns about the integrity and security of cached data. Different from centralized cloud servers, fog nodes are distributed and have limited computing and communication capabilities. Therefore, the direct adoptions of the existing centralized data integrity assurance schemes would incur significant communication overheads and cannot meet the real-time requirements of the fog-based applications. In this article, we propose an efficient and secure collaborative cached data auditing scheme for distributed fog computing. The proposed scheme, named FogAudit, enables untrusted fog nodes to collaboratively provide caching services while protecting the integrity and security of cached data. Our design can efficiently support fog nodes to collaborate with each other to identify malicious nodes and realize data recovery without relying on a centralized authority. Besides, we devise ESV, a tailored auditing protocol based on distributed consensus mechanism to handle disputes in the process of collaborative auditing. We provide a formal security analysis and experimentally evaluate its performance against three representative auditing schemes. Our security analysis and experimental evaluation results confirm that FogAudit is efficient and secure.