Quantum key distribution (QKD) theoretically provides unconditional security between remote parties. However, guaranteeing practical security through device characterisation alone is challenging in real-world implementations due to the multi-dimensional 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 multi-dimensional side channel attack in the source. Here, we demonstrate a practical implementation of SCS-QKD, achieving a secure key rate of 6.60 kbps through a 50.5 km fibre and a maximum distribution distance of 101.1 km while accounting for finite-size effects. Our experiment also represents an approximate forty-times improvement over the previous experiment.
@article{arxiv.2504.19242,
title = {Experimental Multi-Dimensional Side-Channel-Secure Quantum Key Distribution},
author = {Hao Dong and Cong Jiang and Di Ma and Chi Zhang and Jia Huang and Hao Li and Li-Xing You and Yang Liu and Xiang-Bin Wang and Qiang Zhang and Jian-Wei Pan},
journal= {arXiv preprint arXiv:2504.19242},
year = {2025}
}