Researchers from the Department of Energy’s Oak Ridge and Los Alamos National Laboratories are working with EPB, a utility and telecommunications company in Chattanooga, Tennessee, to test the effectiveness of metro-scale quantum key distribution (QKD) as a means of secure communication for the nation’s electricity suppliers.

Electrical substations can be vulnerable to cyber attacks. Source: Dover Air Force BaseQKD relies on what the researchers said is the inherent randomness of quantum mechanics to authenticate and encrypt data. The technology allows two parties to share a secret key and alerts both parties to any third-party intrusion. That function is seen as a critical security capability as more of the nation’s grid data is moved online.

(Read "Cyber defense tool is an early warning for system for grid attacks")

The goal of this initial demonstration is to prove the interoperability of disparate QKD systems. Because utilities are largely regional, providers use a mix of components and have a range of upgrade schedules. The researchers said that ensuring different utility providers can operate in sync across the electric grid is critical to realizing the potential of QKD on a national scale.

This initial milestone is part of the team’s three-year project focused on next-generation grid security. This research was supported by the Department of Energy’s Office of Cybersecurity, Energy Security and Emergency Response.

Third key's a charm

As part of the test, ORNL researchers modified a commercial QKD system and Los Alamos researchers developed a separate, custom system in-house. As part of the test, both systems generated separate keys that, when interfaced at a trusted node or secure information exchange, generated a third key. This third key then was distributed between the two laboratory systems.

The test showed that different systems can operate together and established the functionality needed to relay keys over the large distances of the electric grid, the researchers said.

The demonstration took place at EPB, which has deployed a fiber optic network along with its electrical distribution infrastructure.

Going the distance

The researchers next will work toward overcoming QKD’s distance limitations. The researchers said that just as electrical resistance reduces the amount of transmitted electricity as distance increases across traditional power lines, increasing the distance of fiber optic transmissions reduces the throughput of quantum communications. For the nation’s electric grid, increasing the distances over which QKD systems can be used is critical, and the researchers plan to use EPB’s electrical substations for this stage of work.

The researchers said the eventual goal is to implement QKD systems in numerous substations, which are capable of relaying the quantum keys. One researcher compared it to a relay race, in which one runner passes the baton to another, with each runner carrying the baton for a certain interval. By passing the "baton" at each substation before the signal is lost, the signal can be refreshed to continue its journey, opening the possibility for significantly expanding the range of QKD technology.