Quantum key distribution from space

Among the most mature applications is secure communications based on ‘quantum key distribution’. Current secure data sharing is based on the sharing of ‘cryptography keys’ between sender and recipient. Today, such keys are normally shared through classical communication channels using mathematical algorithms or by human couriers.

As a more secure alternative, quantum key distribution exchanges keys based on quantum physical properties of light particles. This can be performed using laser links from satellites, to cover much larger distances compared to optical fibres where the quantum signals are more quickly perturbed.