Practical Long-Distance Side-Channel-Free Quantum Key Distribution
Xiang‐Bin Wang, Xiao‐Long Hu, Zong‐Wen Yu · Physical Review Applied · 2019
Quantum key distribution (QKD) can provide secure communication even when an eavesdropper (the villainous ``Eve'') completely controls the channel. In practice, though, side-channel effects exist due to device imperfections, and Eve can still intercept information via a side channel. Thus the authors devise a QKD scheme that is both free of side channels in the source state and measurement-device-independent. While some other protocols can also achieve side-channel-free security, this one is based on mature technology without any demand for local detection efficiency, and works for distances greater than 200 km, even though the misalignment error rate may be as large as 20%.