Designing a Full-Stack, Entanglement-Based Quantum-Secure Network
At Quantum World Congress, Michael Cubeddu—Co-founder and VP of R&D at Aliro Quantum—delivered a sweeping look at how quantum networking has matured from early testbeds to deployable, production-grade systems. Cubeddu framed this year’s inflection point clearly: entanglement-based networks have moved from theory to scalable architecture—and they’re ready for real-world security use cases today.
“Entanglement-based networking must coexist with today’s infrastructure—quantum will only scale if it runs on the fiber already in the ground.”
Cubeddu began by charting the rapid growth of quantum networking initiatives across the United States and abroad. Over just the last 12–18 months, he noted an “explosion of demand” for entanglement distribution technologies—driven by government testbeds, regional technology consortia, and a major wave of investment from the quantum computing sector itself. The reason is simple: the future of utility-scale quantum computing depends on networking. Just as classical HPC transitioned from monolithic machines to distributed systems, fault-tolerant quantum systems will require robust interconnects and scalable quantum networks.
He also pointed to the emergence of a global “quantum space race,” where satellite-based quantum links are being explored as a complement—or even an alternative—to undersea cable infrastructure. Nations are adapting free-space optical systems to quantum applications, motivated in part by China’s advancements in quantum satellite communications.
From there, Cubeddu turned to the core of his talk: a full-stack BBM92 entanglement-based quantum secure communications network. Unlike math-based post-quantum cryptographic algorithms—which rely on new hardness assumptions—entanglement-based quantum key distribution (QKD) uses the laws of physics themselves to guarantee security. In Aliro’s architecture, entangled photons are generated, distributed over standard optical fiber, detected, synchronized, and transformed into 256-bit keys that feed directly into existing networking infrastructure.
A central theme was coexistence: quantum networking cannot require the reinvention of national fiber infrastructure. Instead, it must run as an underlay to today’s routers, switches, and encryptors. As an example, Cubeddu highlighted Aliro’s work with Cisco to integrate QKD-generated keys into IPSec-based VPNs—changing only the source of the keys, not the protocols themselves, to become quantum-safe.
Building these networks, however, introduces major engineering challenges: photon fragility, fiber instability, timing mismatches, and reliability at metro-scale distances. Aliro addressed this using simulations, digital twins, and emulation to validate network design, hardware compatibility, and control-plane behavior before deployment.
Cubeddu emphasized that quantum networking isn’t a single-architecture field—multiple qubit modalities, wavelengths, and degrees of freedom coexist. To support this diversity, Aliro has now integrated more than 50 quantum devices across optics, photonics, and switching into its software stack. This interoperability makes it possible to tailor networks to specific topologies, performance needs, and future applications—whether secure communications, distributed quantum sensing, or eventually, multi-node quantum computing.
He closed by drawing a historical analogy to ARPANET: early local area networks, then metropolitan networks, then interconnections—and then the emergence of applications nobody predicted. The mission now, he said, is to build quantum networks with security and scalability from the start, ensuring interoperability across vendors and architectures so the field can scale from metro fiber links to satellite connections and beyond.
“Let’s apply the lessons of the Internet,” Cubeddu concluded, “and build quantum networks designed for the future—not retrofitted after the fact.”
