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arXiv · 2505.10868

Security Analysis of Mode-Pairing Quantum Key Distribution with Flexible Pairing Strategy

Yi-Fei Lu·Yang Wang·Yan-Yang Zhou·Yu Zhou·Xiao-Lei Jiang·Xin-Hang Li·Hai-Tao Wang·Jia-Ji Li·Chun Zhou·Hong-Wei Li·Yu-Yao Guo·Lin-Jie Zhou·Wan-Su Bao
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Abstract

Mode-pairing quantum key distribution (MP-QKD) is advantageous for long-distance secure communication, leveraging its simple implementation and quadratic scaling capacity. The post-measurement pairing in MP-QKD alleviates the photon-coincidence demands, which is essential for surpassing the fundamental limit to the key-rate transmission. In this work, we propose an improved decoy-state MP-QKD protocol featuring a flexible and efficient pairing strategy. We prove the security of the proposed scheme by presenting an entanglement model for decoy-state MP-QKD. The simulation results show that the secret key rate (SKR) can be enhanced among all distances. Notably, compared with the original scheme [Nature Communication 13, 3903 (2022)], the improvement of SKR is greater than 65\% within 375 km in the asymptotic case and greater than 50\% within 400 km in the finite case. And the achievable distance can be extended in the finite case, especially with a small block length. The simulation results demonstrate the high efficiency of the proposed scheme, which is expected to promote the practical applicability of MP-QKD. Furthermore, the entanglement model could provide a theoretical framework for further security and performance analysis of decoy-state MP-QKD.

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Yi-Fei Lu, Yang Wang, Yan-Yang Zhou, Yu Zhou, Xiao-Lei Jiang, Xin-Hang Li, Hai-Tao Wang, Jia-Ji Li, Chun Zhou, Hong-Wei Li, Yu-Yao Guo, Lin-Jie Zhou, Wan-Su Bao. 2025-05-16. Security Analysis of Mode-Pairing Quantum Key Distribution with Flexible Pairing Strategy. https://doi.org/10.1364/oe.562638

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