Measurement-device-independent quantum key distribution with uncharacterized coherent sources

Measurement-device-independent quantum key distribution (MDI-QKD) is proposed to close all possible side channel detector attacks. The security of the original proposal relies on the assumption that the legitimate users can characterize their sources exactly, which might not be satisfied in practice. Later, some MDI-QKD protocols with uncharacterized qubit sources are proposed to remove the assumption that legitimate users must characterize their encoding states. Here we propose a MDI-QKD with uncharacterized coherent sources. The assumption is that legitimate users only ensure that sources, for encoding, are coherent sources (can be expressed as a mixture of Fock states), while the accuracy of the encoding operations and the intensity of the coherent sources cannot be characterized exactly by them. Based on this assumption, we derived the formulas of the security bounds for it under collective attacks, and simulation results of the security bounds are also presented by employing parameters of current QKD technology. It shows that the lower bound of performance can cover long distances.