Quantum key distribution (QKD) is a family of protocols for growing a private encryption key between two parties. Despite much progress, all ground-based QKD approaches have a distance limit due to atmospheric losses or in-fibre attenuation. These limitations make purely ground-based systems impractical for a global distribution network. However, the range of communication may be extended by employing satellites equipped with high-quality optical links. This manuscript summarizes research and development which is beginning to enable QKD with satellites. It includes a discussion of protocols, infrastructure, and the technical challenges involved with implementing such systems, as well as a top level summary of on-going satellite QKD initiatives around the world.
@article{arxiv.1707.03613,
title = {Progress in satellite quantum key distribution},
author = {Robert Bedington and Juan Miguel Arrazola and Alexander Ling},
journal= {arXiv preprint arXiv:1707.03613},
year = {2017}
}