On the path to a plug-in network card for quantum cybersecurity

For DARPA's QuANET program, Leidos is developing a device designed to connect to existing network hardware and expose physical-layer attacks

Three Points to Remember 

1. While network intrusion detection systems can flag threats they encounter, data can still be intercepted by malicious actors as it travels through transmission mediums like cables and fiber optics.  
2. Encoding network data streams with naturally occurring quantum signals can enable the smallest signs of tampering to be seen and make it nearly impossible for cyberattacks to go undetected.
3. Through photonic integrated circuit technology, Leidos aims to take a multiple-rack laboratory device that enables quantum communications and security and reduce it to the size of a desktop graphics processor. 

Imagine a network as a bustling digital city: servers are skyscrapers, data packets are citizens and information flows like traffic on highways. In this metropolis, network intrusion detection systems act like police checkpoints, as they monitor traffic, check IDs, flag suspicious behavior and stop bad actors from sneaking in. They’re good (very good) but not infallible.

While these checkpoints protect much of the city, the roads and tunnels carrying all the traffic remain vulnerable. This “physical layer” of a network is where data actually travels through cables, fiber optics and wireless signals. Here, sophisticated attackers can quietly tap into the traffic without setting off alarms — much like criminals burrowing beneath the streets to bypass the checkpoints. These physical-layer attacks can’t be seen by traditional defenses that only monitor what’s on the surface.

This is where quantum detection changes the game. Unlike the checkpoints that only see what passes through, it acts like a watchtower high above and can detect the tiniest disruptions in the particles that carry data to help reveal tampering as it begins. By using the laws of quantum physics, it's nearly impossible for intruders to hide their activities.

Leidos is developing a compact quantum network interface card, or qNIC, for quantum communications that is designed to plug into today’s network hardware. The qNIC would enable quantum capabilities for existing infrastructure. Under development for the Defense Advanced Research Projects Agency’s (DARPA) Quantum Augmented Network (QuANET) program, and dubbed Equinox, the solution could potentially redefine cybersecurity by making quantum security practical.

QuANET explores how integrating quantum and classical approaches to networking could provide quantum physics-based security capabilities for critical network infrastructures. The program seeks to enable the use of quantum systems that incorporate quantum communications in various ways.

To deliver quantum security, Equinox addresses two key challenges. The first is creating practical hardware. The second is making that new hardware integrate effectively with today’s existing network infrastructure. Using an approach called quantum-classical link aggregation (QCLA), Equinox combines quantum and traditional network signals to work together. 

QCLA could provide quantum sensing capability without relying on quantum key distribution (QKD), a method that uses quantum particles to exchange encryption keys. QKD has significant security concerns in real-world implementations due to the modification of proven cryptography with novel quantum components. QCLA takes a different approach in layering capabilities on top of existing cryptography to enhance the security of the traditional link while improving the speed of the quantum link.

What the quantum network interface card could mean

"Our work on the Equinox solution within the DARPA QuANET program represents a breakthrough leap in cybersecurity, combining quantum and classical networking to deliver new levels of protection for network systems,” said Chaise Farrar, Leidos’ principal investigator and manager of cyber-electromagnetic activities threats. “It helps ensure that our nation's networks are equipped to detect and counter sophisticated threats at the physical layer — where traditional defenses fall short."

In quantum research labs, the equipment to send and detect quantum signals fills entire racks. Cooling systems, lasers and sensors stack six feet high. These setups are delicate, expensive and far too large for many pertinent applications. 

Through the use of photonic integrated circuits that it is designing, Leidos aims to compress full lab systems onto a single microchip that would enable the miniaturization to bring quantum technology out of research environments and into real-world missions.

The qNIC would be roughly the size of a desktop graphics processor with a familiar, easy-to-deploy format. The device is intended to be a single, rugged card that slides into a computer or server through standard connecting ports.

It would operate as two distinct but integrated systems: a quantum sensor that provides continuous health monitoring and anomaly detection of the physical link, and an information carrier that aggregates this quantum sensing data with classical network data streams.

In a recent test-and-evaluation setting, Leidos’ Equinox team was able to send quantum signals alongside classical signals over a 5.2-kilometer (3.2-mile) loop of fiber optics successfully. Both classical and quantum signals were within the telecom C-band. Additionally, the team was able to detect anomalies with a success rate above 72% and an average discovery time of 5.98 seconds.

Transforming networks with quantum capabilities

As part of DARPA’s multi-year QuANET program, Leidos’ Equinox solution is intended to help government networks reach a new level of protection by adding quantum sensing to the systems already in use. This capability would enable agencies to detect eavesdropping or tampering at the physical, data-transfer layer before the threats can cause harm.

Equinox is progressing in stages. Full deployment in the field and even in space missions is targeted within the next several years, after the technology has shown the speed, reliability and resilience required for mission-critical operations.

“By developing the qNIC, Leidos is transforming quantum research into practical, deployable solutions,” Farrar noted.

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The views, opinions and/or findings expressed are those of the author and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. government.

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