Measurement-device-independent quantum key distribution with heralded pair coherent state

摘要

Measurement-device-independent QKD (MDI-QKD) can solve security loophole problems brought by imperfections of detectors and provide enhanced practical security compared to traditional QKD. We propose an active-passive-combined decoy state MDI-QKD protocol with heralded pair coherent state (HPCS) source. By calculating the lower bound of the single-photon counting rate and the upper bound of the single-photon error rate, we present formulas of the secure key rate in our protocol. Based on the linear lossy channel model, we present calculation methods of estimating the overall gain and quantum bit error rate for HPCS source with full phase randomization. We numerically compare secure key rates for different decoy MDI-QKD protocol with different sources. The result shows that the active-passive-combined decoy state MDI-QKD protocol with HPCS source has certain superiority in the secure key rate. It can provide an important theoretical reference for practical implementations of MDI-QKD.