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Experimental side channel secure quantum key distribution under realistic conditions

Hao Dong1,2, Cong Jiang2,3, Di Ma2, Chi Zhang2, Jia Huang4, Hao Li4, Li-Xing You4, Yang Liu1,2,3, Xiang-Bin Wang2,3,5 et al.

Qiang Zhang1,2,3 and Jian-Wei Pan1,3

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Phys. Rev. Research 8, 013214 – Published 25 February, 2026

DOI: https://doi.org/10.1103/fxxb-9y8n

Abstract

Quantum key distribution (QKD) theoretically provides unconditional security between remote parties. However, guaranteeing practical security through device characterization alone is challenging in real-world implementations due to the multidimensional spaces in which the devices may be operated. The side channel secure (SCS) QKD protocol, which only requires bounding the upper limits of the intensities for the two states, theoretically provides a rigorous solution to the challenge and achieves measurement-device-independent security in detection and security for whatever multidimensional side channel attack in the source. Here, we demonstrate a practical implementation of SCS-QKD, achieving a secure key rate of 6.67 kbps through a 50.5 km fiber and a maximum distribution distance of 101.1 km while accounting for finite-size effects. Our experiment also represents an approximately 40 times improvement over the previous experiment.

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Phys. Rev. Research 8, 013214– Published 25 February, 2026
  • Received 25 April 2025
  • Accepted 23 January 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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