Coherent one-way quantum key distribution (COW-QKD) has been widely investigated, and even been deployed in real-world quantum network. However, the proposal of the zero-error attack has critically undermined its security guarantees, and existing experimental implementations have not yet established security against coherent attacks. In this work, we propose and experimentally demonstrate an information-theoretically secure COW-QKD protocol that can resist source side-channel attacks, with secure transmission distances up to 100 km. Our system achieves a secure key rate on the order of kilobits per second over 50 km in the finite-size regime, sufficient for real-time secure voice communication across metropolitan networks. Furthermore, we demonstrate the encrypted transmission of a logo with information-theoretic security over 100 km of optical fiber. These results confirm that COW-QKD can simultaneously provide simplicity and security, establishing it as a strong candidate for deployment in small-scale quantum networks.
@article{arxiv.2601.06772,
title = {Experimental Coherent One-Way Quantum Key Distribution with Simplicity and Practical Security},
author = {Xiao-Yu Cao and Xiao-Ran Sun and Ming-Yang Li and Yu-Shuo Lu and Hua-Lei Yin and Zeng-Bing Chen},
journal= {arXiv preprint arXiv:2601.06772},
year = {2026}
}