Reference-frame-independent measurement-device-independent quantum key distribution with imperfect sources

TL;DR

This paper introduces a robust RFI-MDI-QKD protocol that tolerates imperfect state preparation, enhancing practical security and simplifying implementation, with simulation showing basis-dependent effects of source flaws.

Contribution

It proposes a new RFI-MDI-QKD scheme resilient to source imperfections, reducing the number of required states and improving practical security.

Findings

Source flaws in Z basis impair performance.

Flaws in X and Y bases have minimal impact.

The scheme simplifies experimental setup.

Abstract

Reference-frame-independent measurement-device-independent quantum key distribution (RFI-MDI-QKD) can remove all potential detector side-channel attacks and the requirement of real-time alignment of reference frames. However, all previous RFI-MDI-QKD implementations assume the perfect state preparation in sources, which is impractical and may lead to security loopholes. Here, we propose a RFI-MDI-QKD protocol which is robust against state preparation flaws. Comparing to the conventional six-state RFI-MDI-QKD, our scheme can be realized with only four flawed states, which improves the practical security of RFI-MDI-QKD and simplifies the experimental implementation. In addition, simulation results demonstrate that source flaws in Z basis have adverse effect on the performance of RFI-MDI-QKD while the source flaws in X and Y bases have almost no effect. We hope that this work could provide a valuable reference for practical implementations of RFI-MDI-QKD.