Reliability-based updating strategies of cyber infrastructures

Cyber security is one critical issue for Internet protocol (IP)-based cyber-physical systems. To protect physical systems from possible malicious intrusions, cyber infrastructures, e.g., firewalls, are installed in systems. However, with more intelligent cyberattacks, existing firewalls may not be advanced enough to protect these intelligent cyberattacks, which increase the probability of outages and reduce system reliability levels. In this case, cyber infrastructures should be updated to deal with more intelligent cyberattacks. This paper proposes a probabilistic method for making decisions about updating strategies of cyber infrastructures. Considering stochastic characteristics of cyberattacks, a reliability-based cost-effective updating model for cyber infrastructures is formulated. The optimal updating strategy balances the system reliability and the cost caused by updating cyber infrastructures. The proposed method is illustrated on the IEEE 30-bus system, and the results show the feasibility for informing updating cyber infrastructures.