First you establish a baseline pattern for a system as it operates normally. PFP sees a particular opportunity in poorly protected infrastructure systems, so take a protective relay for example. That's a device used to sense and cut off voltage surges on power lines.
Once the power signature for the device is recorded, PFP's monitor can detect even the smallest change in that pattern. Maybe the relay has stopped functioning properly—or perhaps a hacker has implanted a piece of malicious code in it. Either way, the technology can alert a human technician to the anomaly within milliseconds.
The technology, made up of sensors and software that analyzes what the sensors pick up, was developed in 2006 at Virginia Tech by Jeffrey Reed, a professor of electrical and computer engineering, and Carlos Aguayo Gonzalez, one of his Ph.D. students at the time. The research was inspired by the side-channel attack, a way of breaking into an encrypted system by analyzing physical signals such as heat and power consumption, says Reed, PFP's president.