Design-time Quantification of Integrity in Cyber-physical Systems

In a software system it is possible to quantify the amount of information that is leaked or corrupted by analysing the flows of information present in the source code. In a cyber-physical system, information flows are not only present at the digital level but also at a physical level, and they are also present to and fro the two levels. In this work, we provide a methodology to formally analyse a composite, cyber-physical system model (combining physics and control) using an information flow-theoretic approach. We use this approach to quantify the level of vulnerability of a system with respect to attackers with different capabilities. We illustrate our approach by means of a water distribution case study.