China implements CN-QCN as a Long-Range Quantum Communication Network:

The rapid development of Quantum Computers poses a serious threat to classical encryption methods, which rely on the complexity of mathematical functions. Due to their enormous computational power, Quantum Computers can break currently used algorithms in a very short time. This is exactly where Quantum Communication comes in: it offers entirely new and secure ways of transmitting data. Quantum Key Distribution (QKD), which leverages the principles of Quantum Mechanics, enables secure key exchange and has proven to be a groundbreaking technology to counter the threat posed by Quantum Computers.

Against this backdrop, China established an integrated space-to-ground Quantum Communication Network in 2020, initially comprising 32 backbone nodes and four metropolitan networks. The latest advances in the development of the so-called China Quantum Communication Network (CN-QCN) have now been presented in a new paper. CN-QCN is an operational, long-range QKD network based on trusted relays, spanning over 10,000 kilometers. It consists of 145 fiber backbone nodes and 20 metropolitan networks covering 17 provinces and 80 cities, as well as 6 ground stations linked with the Quantum microsatellite Jinan‑1.

CN-QCN not only surpasses its predecessor, the Beijing-Shanghai Backbone Network (BSBN), but also achieves significant advances in multi-type QKD hybrid networking, as well as in the operation and maintenance of large-scale Quantum Networks. The new article details the network architecture, the QKD implementation, and the long-term performance of CN-QCN, laying the foundation for the widespread application of QKD in China.

Source reference: https://www.nature.com/articles/s41534-025–01089‑8?utm_source=nature_etoc&utm_medium=email&utm_campaign=CONR_41534_AWA1_GL_DTEC_054CI_TOC-250827&utm_content=20250827

Source：https://www.squad-germany.de/en/qkd-network-implementation-across-10000-kilometers/