Keys from the Sky: A First Exploration of Physical-Layer Security Using Satellite Links

In this paper, we investigate physical-layer security (PLS) methods for proximity-based group-key establishment and proof of location. Fields of application include secure car-to-car communication, privacy-preserving and secure distance evidence for healthcare, or location-based feature activation. Existing technologies do not solve the problem satisfactorily due to communication restrictions, e.g., ultra-wideband (UWB) based time of flight measurements, or trusted hardware, e.g., using global navigation satellite system (GNSS) positioning data.We introduce PLS as a possible solution candidate. It is information-theoretically secure, thereby also post-quantum resistant, and has the potential to run on resource-constrained devices with low latency. We use wireless channel properties of satellite-to-earth links, demonstrate the first feasibility study using off-the-shelf hardware testbeds, and present first evaluation results and future directions for research.