ReFQ: Modular WCP Sources & RFI Protocols for Space-based QKD Demonstrations

Quantum Key Distribution (QKD) is expected to form a critical part of future secure communications infrastructure. Keys are a highly valuable cryptographic tool for securing valuable and sensitive data. Current key methods protect transactions including mobile telephony, corporate intellectual property, diplomatic cables and financial transactions.

The distribution of keys to global communication nodes within a network presents a challenge commonly addressed using computationally hard mathematics, such as calculating the prime factors of large numbers. Security for these keys is therefore based on the premise that the computational cost remain impractically high and expensive relative to the value of the data.

This premise is now under threat from mathematical advancement and quantum computing where the ability to factor large numbers becomes significantly less challenging. Should these keys be compromised, all data and nodes on the network using these methods becomes vulnerable to interception and cyberattack.

QKD provides a'quantum-safe' solution for sharing keys assured by fundamental physics. Space provides an ideal and highly scalable medium for key distribution, given that a satellite can deliver keys globally over long distances as it flies about an orbit. Space-based QKD is therefore expected to complement ground based local QKD networks which are already beginning to emerge.

Satellites will provide these keys to ground nodes globally for use in existing telecommunication networks, particularly to remote locations or across international boundaries.

This work leverages ongoing mission developments in the UK and Canada bringing together the two teams responsible for upcoming QKD missions: QEYSSAT in Canada including Honeywell and University of Waterloo, and ROKS in UK including Craft Prospect, and the Universities of Bristol and Strathclyde. The work will allow a UK based QKD technology to fly on the QEYSSAT mission, providing valuable performance data for the system and extending the capabilities of the satellite to perform another class of QKD link.

It will additionally allow the development of new protocols for secure key distribution from space overcoming challenges resulting from the motion of the satellitejunderstanding of interoperability, ready for adoption as the security of existing approaches becomes more open to challenge and cyberattack.