Improved Coherent One-Way Quantum key Distribution for High-Loss Channels
Emilien Lavie, Charles Ci Wen Lim · Physical Review Applied · 2022
Coherent one-way quantum key distribution (COW-QKD) is a popular cryptography protocol, due to its fairly simple implementation and passive measurement device. Its security analysis is challenging, though, and extra assumptions or modifications are typically employed. Here the authors propose minor modifications to COW-QKD's prepared states while retaining the original, fully passive measurement device, and generalize the ``universal squashing'' framework to analyze their system's security. The results suggest that performance should be comparable to upper bounds from the literature, making this protocol a viable alternative to one based on phase-modulated coherent states.