Informatics Researchers Develop Hybrid Quantum-Secure Communication Protocol

The protocol, developed by Kaushik Chakraborty, Mina Doosti, Myrto Arapinis, and Elham Kashefi from the School of Informatics, in collaboration with Yao Ma (Sorbonne Université) and Chirag Wadhwa (Indian Institute of Technology Roorkee), integrates physical unclonable functions (PUFs) with quantum key distribution (QKD) techniques. This hybrid approach addresses a longstanding challenge in quantum cryptography: authentication.

PUFs are hardware-based security primitives that exploit the inherent randomness of physical devices to generate unique identifiers. While lightweight and widely applicable, PUFs alone are vulnerable to sophisticated attacks. The new protocol enhances their security by encoding PUF outputs into non-orthogonal quantum states, creating what the researchers call “Hybrid Locked PUFs” (HLPUFs). These HLPUFs are protected by a quantum lock that prevents adversaries from accessing the underlying classical data.

This innovation eliminates the need for separate authentication channels, combining authentication and key exchange into a single protocol. It also significantly increases the secret-key rate compared to conventional QKD methods, making it a more efficient solution for quantum-secure communications.

The research was published in Quantum under the title “Quantum Lock: A Provable Quantum Communication Advantage.” The team demonstrated that their protocol is not only theoretically sound but also practically implementable using existing quantum communication technologies. Their simulations show a clear security advantage over classical PUF systems, even under optimal machine learning-based attacks.

Technology validation is currently underway, and a PCT patent application was filed in May 2025. The technology is available for licensing through Edinburgh Innovations.