Measurement-device-independent quantum key distribution protocol with phase post-selection

摘要

Measurement-device-independent quantum key distribution(MDI-QKD)protocol can remove all the loopholes of the detection devices and,thus,has attracted much attention.Based on the technique of single-photon interference,we propose a modified MDI-QKD protocol with phase post-selection.We prove the security of the announcement of the private phases in the X basis and show how to apply the phase post-selection method to the double-scanning four-intensity MDI-QKD protocol.The numerical results show that the phase postselection method can significantly improve the key rates at all distances.In the double-scanning method,two parameters need to be scanned in the calculation of the final key rate,and the global parameter optimization is pretty time-consuming.We propose an accelerated method that can greatly reduce the running time of the global parameter optimization program.This makes the method practically useful in an unstable channel.