Cybersecurity, Utility, Transparency, Discrete Event Systems
Abstract
A property related to the security of Cyber-Physical Systems (CPSs) that aims to hide sensitive information from an agent who gains unauthorized access to the industrial communication network is called opacity. A system is said to be opaque when sensitive information is preserved in a passive cyber attack. However, this information will be hidden from legitimate receivers, such as a SCADA application in an opaque system. Therefore, the availability of system information, known as utility, to trustworthy agents is fundamental to operating such applications efficiently. In this paper, a new notion of utility, called Property-Based Transparency (PBT), is defined. A system is said to be transparent if legitimate receivers can determine whether a given property is satisfied in the system before that property becomes false. A method for verifying PBT and a case study are presented to show that, in some cases, the same data can be transparent to legitimate receivers and opaque to unauthorized agents.
