The continued maturation of quantum technology into mainstream and commercial applications will eventually render current encryption technology insufficient for protecting our information.
Such advances in quantum computing also provide an opportunity to develop quantum-safe encryption solutions using Quantum Key Distribution (QKD). However, conventional QKD infrastructure does not allow for implementing QKD encryption solutions over large distances, limiting application internationally or within countries having large geographic boundaries. In search of solutions, outer space may prove to be the ingredient required to unlock the true potential of QKD encryption.
QKD is an encryption protocol based on quantum mechanics used only to generate and distribute an encryption key. More particularly, QKD implements a ‘sender’ to transmit photons through a polarizer (or filter) to alter the quantum state of the photons. A ‘receiver’ then receives and assesses the polarization of each photon to determine a sequence of bits for generating an encryption key known only to the sender and receiver. In essence, QKD relies on the fact that photons cannot be copied or manipulated without generating detectable changes in the photons. As such, QKD is particularly resilient to third party interceptions which produce detectable anomalies, thereby alerting of an outside presence.
Existing fibre optic QKD systems are limited, however.
Transmitting photons through fibre optic cables becomes unreliable when transmitting photons over large distances, such as transmitting in excess of 200 kilometers, making fibre optic based QKD systems unsuitable over large geographic areas. While development continues on ground-based quantum repeaters for extending the operational capacity of fibre optic based QKD infrastructure, it is not clear when such technology will mature and become more widely available. Accordingly, to develop a more robust global QKD infrastructure, communication systems will need to turn to transmission mediums beyond fibre optic cables.
To address shortcomings in existing systems, the Government of Canada via the Canadian Space Agency (CSA) in 2017, green-lit the development of the Quantum Encryption and Science Satellite (QEYSSat) space mission. The aim of QEYSSAT is to study how QKD behaves in space, laying the groundwork for an international QDK network using microsatellites to link a ‘sender’ ground station with a ‘receiver’ ground station. While the microsatellite does require direct line-of-sight to each ground station, the distance between sender and receiver ground stations can nevertheless extend well beyond the limitations of conventional fibre-optic based systems, allowing QEYSSat to implement QKD encryptions solutions across large geographic boundaries, all over the world.
The QEYSSat space mission also demonstrates the collaborative potential between public and private sector for advancing quantum technology.
As key partners in QEYSSat, CSA selected the University of Waterloo’s Institute of Quantum Computing to lead science on the mission, and Honeywell to build, test, deliver, and provide training on ground stations. More recently, CSA awarded a Space Technology Development Program (STDP) contribution to Kitchener based evolutionQ, a quantum-safe cybersecurity company, for the development of solutions to advance satellite-based secure quantum communication services and tools to address challenges related to satellite-based Quantum Key Distribution (QKD) networks.
Thus, as we near the 2023 anticipated launch, the QEYSSat mission aims to change the potential of space based QKD into reality, unlocking exciting possibilities for the future of quantum-safe encryption.