Security in the Cyber-Physical Electric Power Infrastructure

The emerging smart electrical grid is a representative application of the growing interaction between computing, communication networks, and physical devices in modern system design. More widely referred to as cyber-physical systems (CPSs), the reliable and sound operation of these systems is of the utmost priority, given how every sector of society and the economy depend on them for day-to-day operation [1, 2]. The compound discrete computational and continuous physical nature of a CPS, however, provokes new system design challenges; not only do these have different semantics from each other, but the notion of system boundaries is blurred from purely cyber or purely physical systems. The embedded computers and communication networks therein govern both physical manifestations and computations, which in turn affect how these two major components interact with each other and the outside world [3]. As we shall see in this chapter, this lack of boundaries creates a host of new security and privacy vulnerabilities. Specifically, changes in the physical portion of the infrastructure are always observable and adversaries to the system can potentially derive sensitive system internal settings by observing these external system changes. This derived knowledge coupled with the semantic knowledge of the system can be used against the system. In terms of system security models centered around the classic CIA1 triad [4], this is a confidentiality violation with serious system integrity and availability breach implications. Moreover, typical system security models are not necessarily adequately expressive in their ability to address these new