First demonstration of a post-quantum key-exchange with a nanosatellite

Abstract: We demonstrate a post-quantum key-exchange with the nanosatellite SpooQy-1 in low Earth orbit using Kyber-512, a lattice-based key-encapsulation mechanism and a round three finalist in the NIST PQC standardization process. Our firmware solution runs on an on-board computer that is based on the Atmel AVR32 RISC microcontroller, a widely used platform for nanosatellites. We uploaded the new firmware with a 436.2 MHz UHF link using the CubeSat Space Protocol (CSP) and performed the steps of the key exchange in several passes over Switzerland. The shared secret key generated in this experiment could potentially be used to encrypt RF links with AES-256. This implementation demonstrates the feasibility of a quantum-safe authenticated key-exchange and encryption system on SWaP constrained nanosatellites.