Towards a Formal Approach Based on Bigraphs for Fog Security: Case of Oil and Gas Refinery Plant

Fog has the advantage of reducing service latency and improving perceived quality, as well as the benefit of total data distribution. However, its security or privacy issues pose major challenges due to the heterogeneity, hierarchical structure, and very large scale infrastructure of Fog architecture. CA-BRS model, an extension of Bigraphical Reactive Systems with Control Agents, is showed to be an appropriate formal semantic framework for Fog architecture specification. It separates, for a complex system, the concerns of computation and physical entities distribution, respectively into two different models: 1) computational or virtual agents' model and 2) physical Bigraph model. The main objective of this paper is twofold; first, we propose a multi-views architecture to Fog computing taking into account security level, then we define, according to this semantic framework, the physical entities of Fog architecture and their geographical dispersion, as well as the virtual entities devoted to represent security functionalities. Our proposal is illustrated through a realistic case study of Oil and Gas Refinery Plant.