Measurement-Device-Independent Quantum Key Distribution over asymmetric channel and unstable channel

Xiao-Long Hu,Zong-Wen Yu,Yuan Cao,Xiang-Bin Wang

doi:10.1038/s41598-018-35507-z

Abstract

We show that a high key rate of Measurement-Device-Independent Quantum Key Distribution (MDIQKD) over asymmetric and unstable quantum channel can be obtained by full optimization and compensation. Employing a gradient optimization method, we make the full optimization taking both the global optimization for the 12 independent parameters and the joint constraints for statistical fluctuations. We present a loss-compensation method by monitoring the channel loss for an unstable channel. The numerical simulation shows that the method can produce high key rate for both the asymmetric channel and the unstable channel. Compared with the existing results of independent constraints, our result here improves the key rate by 1 to tens of times in typical experimental conditions.

Highlights

Quantum key distribution (QKD) provides the communication users with secure keys to encrypt their information
Directly applying the optimized parameters for symmetric channel does not give a good performance in an asymmetric channel or an unstable channel
We propose full optimization of four-intensity decoy-state Measurement-Device-Independent Quantum Key Distribution (MDIQKD) protocol to largely increase the key rate in asymmetric channels than existing results of partial optimization

Summary

Quantum Key Distribution over asymmetric channel and unstable

We show that a high key rate of Measurement-Device-Independent Quantum Key Distribution (MDIQKD) over asymmetric and unstable quantum channel can be obtained by full optimization and compensation. BB84 protocol with imperfect single-photon sources would suffer from the photon-number-splitting (PNS) attack[2,3,4] This loophole can be fixed by the decoy-state method[5,6,7,8]. The maximum distance of MDIQKD has been experimentally increased to 404 kilometers[38] using the 4-intensity protocol[24] with joint constraints for statistical fluctuations[23] Another experiment exceeding 400-kilometer distance applying the decoy-state method but not using MDIQKD scheme was reported recently[43]. We propose full optimization of four-intensity decoy-state MDIQKD protocol to largely increase the key rate in asymmetric channels than existing results of partial optimization. A loss-compensation method is presented with optimization to increase the performance of MDIQKD in unstable channels

Results

In the case that both

Discussion

Additional Information