Satellite-based multi-user quantum conference key agreement

Abstract

Quantum communication is evolving as the next generation of secret sharing technology. Compared to the rapid development in bipartite quantum communications, multipartite quantum network still awaits significant improvements in transmission distances, covering areas, and number of users. Current fiber-based quantum networks are challenged by preparing multi-particle entangled states and the high loss of fiber links. Inspired by the source-independent quantum conference key agreement based on Bell states and the satellite-to-ground transmission links, we proposed two satellite-based quantum network architectures, including up-links and down-links. The simulated key rates are maintained when the number of users increases for both two proposed architectures. The down-link architecture ensures a secure key rate exceeding \(10^{-7}\) bit/pulse even over a distance of 1000 km. Our work offers viable solutions and quantitative references toward realizing scalable satellite-based secure quantum communication networks.