On the impact of emergent properties on SoS security

Cyber security is becoming more and more relevant with the advent of System of Systems (SoSs). The latter are large scale systems made of independent and autonomous Constituent Systems which interoperate to achieve higher level goals also with the intervention of humans. Providing security in a cyber-physical SoS means, among other features, forecasting and anticipating evolving SoS functionalities and consequently detecting emerging phenomena resulting from the interactions among entailed Constituent Systems. This paper clarifies the relations occurring among SoS evolution, emergence phenomena and security requirements. We show how to enact an evolution step by means of changing SoS functionalities and how to perform the threat analysis consequently. An illustrative scenario in the Smart City domain shows how to dynamically generate security guarantees according to the evolving SoS thus supporting the enactment of mitigation strategies from SoS administrators.