Hajomer Adnan A E, Kanitschar Florian, Jain Nitin, Hentschel Michael, Zhang Runjia, Lütkenhaus Norbert, Andersen Ulrik L, Pacher Christoph, Gehring Tobias
Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
Vienna Center for Quantum Science and Technology (VCQ), Atominstitut, Technische Universität Wien, Stadionallee 2, 1020, Vienna, Austria.
Light Sci Appl. 2025 Jul 28;14(1):255. doi: 10.1038/s41377-025-01924-9.
Establishing secure data communication necessitates secure key exchange over a public channel. Quantum key distribution (QKD), which leverages the principles of quantum physics, can achieve this with information-theoretic security. The discrete modulated (DM) continuous variable (CV) QKD protocol, in particular, is a suitable candidate for large-scale deployment of quantum-safe communication due to its simplicity and compatibility with standard high-speed telecommunication technology. Here, we present the first experimental demonstration of a four-state DM CVQKD system, successfully generating composable finite-size keys, secure against collective attacks over a 20 km fiber channel with 2.3 × 10 coherent quantum states, achieving a positive composable key rate of 11.04 × 10 bits/symbol. This accomplishment is enabled by using an advanced security proof, meticulously selecting its parameters, and the fast, stable operation of the system. Our results mark a significant step toward the large-scale deployment of practical, high-performance, cost-effective, and highly secure quantum key distribution networks using standard telecommunication components.
建立安全的数据通信需要在公共信道上进行安全的密钥交换。利用量子物理原理的量子密钥分发（QKD）能够实现具有信息理论安全性的密钥交换。特别是离散调制（DM）连续变量（CV）QKD协议，由于其简单性以及与标准高速电信技术的兼容性，是大规模部署量子安全通信的合适候选方案。在此，我们展示了四态DM CVQKD系统的首次实验演示，成功生成了可组合的有限尺寸密钥，在20公里光纤信道上，面对集体攻击时安全可靠，使用了2.3×10个相干量子态，实现了11.04×10比特/符号的正可组合密钥率。这一成果得益于采用先进的安全性证明、精心选择参数以及系统的快速稳定运行。我们的结果标志着朝着使用标准电信组件大规模部署实用、高性能、经济高效且高度安全的量子密钥分发网络迈出了重要一步。
