Orchestrator for ensuring interdependency between safety and cybersecurity in railway control systems

Nowadays, more and more cyber-attacks are documented in transportation systems and this impacts human and environment. Thus, it is important to consider the integration of safety and cybersecurity in both industry and academia. This brings many advantages such as virtualization technologies, but it also creates new vulnerabilities. However, a safety orchestrator that is able to address a variety of safety anomalies that come from safety-related properties and to avoid conflicts with the functionalities of a cybersecurity orchestrator is not found in the literature. To reply to this need, in this paper we propose a new safety architecture for the railway systems. The core of this architecture is STELAC, the first safety orchestrator. This orchestrator covers reliability, availability, maintainability, and integrity-related anomalies as they are the properties which interact and influence safety according to RAMS. This orchestrator is also able to prevent functionality violations between safety and cybersecurity, in order to handle their interdependency. According to the results of the implementation, it is shown that STELAC ensures safety affected by the rest of the aforementioned properties and has little impact on decision-making time, which makes it an effective methodology for using the NFV architecture in railway systems safely and securely.