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

量子密钥分发（QKD）有望成为未来安全通信基础设施的关键组成部分。密钥是一种非常有价值的加密工具，用于保护有价值和敏感的数据。目前的关键方法保护的交易包括移动电话、企业知识产权、外交电报和金融交易。将密钥分发到网络内的全局通信节点是一个难题，通常使用计算难度较大的数学来解决，例如计算大数的质因数。因此，这些密钥的安全性是基于这样一个前提：相对于数据的价值，计算成本仍然高得不切实际。这个前提现在受到数学进步和量子计算的威胁，在量子计算中，分解大数的能力变得不那么具有挑战性。如果这些密钥被泄露，使用这些方法的网络上的所有数据和节点都容易受到拦截和网络攻击。QKD提供了一种“量子安全”的解决方案，用于共享由基础物理保证的密钥。太空为密钥分发提供了一个理想的、高度可扩展的媒介，因为卫星可以在绕轨道飞行时远距离在全球范围内传递密钥。因此，天基QKD有望补充已经开始出现的地面本地QKD网络。卫星将向全球地面节点提供这些钥匙，供现有电信网络使用，特别是向偏远地区或跨越国际边界使用。这项工作利用了英国和加拿大正在进行的任务发展，将负责即将到来的QKD任务的两个团队聚集在一起：加拿大的QEYSSAT，包括霍尼韦尔和滑铁卢大学，以及英国的ROKS，包括Craft Prospect，布里斯托尔大学和斯特拉斯克莱德大学。该工作将允许基于英国的QKD技术在QEYSSAT任务上飞行，为系统提供有价值的性能数据，并扩展卫星执行另一类QKD链路的能力。此外，它还将允许开发用于从空间安全分发密钥的新协议，以克服卫星对互操作性理解的变化所带来的挑战，并在现有方法的安全性对挑战和网络攻击变得更加开放时准备采用。

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.