Key generation analysis for satellite quantum key distribution

Developing global quantum communication networks is integral to the realisation of the quantum internet, which is expected to impart a similar revolutionary impact on the technological landscape as the classical internet. Satellite-based quantum communications provides a practical route to global quantum networking. In this work, we model finite statistics to determine the finite secret key length generation in SatQKD systems that implement trusted-node downlink operation with weak coherent pulse sources. We optimise the finite key rate for different practical operations and determine the key generation footprints. Our work provides an essential guide for future satellite missions to establish performance benchmarks for both sources and detectors.