Dynamic zoning based on situational activitie for ICS security

In the previous paper, the authors proposed a design methodology of zones and conduits not only to isolate incidents caused by cyber-attacks but also to detect higher possibility of cyber-attacks and keep sufficient operability by evaluating process safety under the attacks. However, process plants generally have several operational modes, such as start-up, load-change and shutdown. In each mode, security and safety requirements should be defined based on the configuration of process and control structures. Therefore, zones and conduits have to be dynamically switched with the associated mode. In this paper, the authors propose a dynamic zoning methodology that is composed of zone design methodology and zone switching methodology.