Using colour to protect electric grids

Inspired by a mysterious human sensory condition, an Oak Ridge National Laboratory (ORNL) researcher has invented a new way to hide sensitive electric grid information from cyber attack: within a constantly changing colour palette.

Peter Fuhr, who heads the Grid Communications and Security group at ORNL, was intrigued by synaesthesia. This lifelong condition causes some people to experience one sense through another, such as perceiving sounds as colours. Fuhr applied this concept to encrypting the ‘language’ of grid management software into colours.

Utilities use a computerised system for gathering and analysing real-time data to monitor and control equipment. That system communicates with hardware using strings of letters. With the ORNL approach, these letters can be translated into colour combinations displayed as bars, wheels or swirls. The colour patterns in turn are faded beneath another image, such as a colourful pointillist painting, or hidden between the frames of a video feed. The decoding key rotates with each sensor reading. It changes based on the Fibonacci Sequence, in which each subsequent number is derived by adding the two previous numbers.

Fuhr said the innovative approach has already drawn attention from private companies interested in licensing. The concept was tested in the field for six months using a secure link between ORNL and the public utility EPB of Chattanooga. The encoded colours are transferred using communication links among video cameras at EPB’s electrical substations.

“It’s not travelling the IT or operating network, which makes it even harder for bad actors to find,” Fuhr said. “And it’s on the video so briefly, it’s just subliminal.” The conscious mind doesn’t register the image.

A central machine receives this sensor data about temperature, pressure, voltage, current and electromagnetic fields, then decodes it automatically. Anything suspicious will immediately alert the utility’s central equipment control system.

Image caption: ORNL researchers encoded grid hardware operating data into a colour band hidden inside photographs, video or artwork, as shown in this photo. The visual can then be transmitted to a utility’s control centre for decoding. Image Credit: ORNL/U.S. Dept. of Energy.

To crack the colour code, Fuhr said, an attacker would have to locate the colour bar, know the equipment’s protocol language and the sensor’s IP address, and rapidly guess the right colour — or letter — combination at the correct point in the Fibonacci sequence.

These layered defences are important for utilities because remote tampering with substation equipment can quickly destabilise the power supply. For example, spoofing a thermal sensor to report a very low temperature might cause fans to shut off. That could cause overheated equipment to fail, triggering a blackout.

More than 100 attacks or incidents of suspicious activity were reported in 2022 at substations across the US. Although many were physical attacks on equipment, the 70% increase in their frequency has raised public concern and led utilities and elected officials to focus on the broader threat posed by cyber sabotage.

Jim Glass, senior manager for smart grid development at EPB, said it was vital for utilities to have a toolbox of cybersecurity approaches. “What makes cybersecurity so much more critical is that if somebody can get access to the secure network that operates utility equipment, it would be as if they’d broken into all the substations at once,” he said. That’s compounded by multiplying points of access to the system: sensors and digital equipment on power poles, smart meters — even smart home technology that utilities may be able to directly control.

Glass said Fuhr’s invention is helpful because it could be combined with a variety of other types of security coding. “And it doesn’t matter what the communication method is. You could secure or hide the data this way to make it very difficult for someone to intercept,” Glass said.

Top image credit: iStock.com/OGphoto