A Resilience-based Security Assessment Approach for Railway Signalling Systems

In order to prompt the level of automation and information, a great amount of common information technologies are applied to railway signalling systems, which brings the openness of signalling systems increasing, and security risks are growing. Quantifying the effects of security risks is an urgent task, which is a great challenge for railway signalling systems due to the lack of security metrics and an efficient assessment approach. In the paper, based on the service features and the cyber-physical characteristics of railway signalling systems, we propose a resilience-based security assessment approach to describe performance changes during different stages of security events, which can illustrate the robustness and recovery capability of signalling systems facing cyber attacks. Considering a typical scenario where malicious jamming attacks are implemented on train-ground wireless communications, the proposed security assessment approach demonstrates the security levels of railway signalling systems. Based on time variance of the resilience indicators, a cognitive control strategy is developed to enhance overall performance and resilience of signalling systems. Simulation results show the validation and efficiency of the proposed security assessment approach.