Satellite Assisted QKD Key Encapsulation

The ever-increasing quantum computational power may pose a serious threat to classical Public Key Exchange (PKE) algorithms in the next few years. The need for quantum resilient key exchange schemes is becoming more topical as quantum computers become more powerful. Quantum Key Distribution (QKD) promises unconditionally secure key distribution between two remote parties. The distilled keys of a QKD link can be used by classical symmetric algorithms such as the Advanced Encryption Standard (AES). Unfortunately, QKD has come across some major limitations in distance reach and Secure Key Rates (SKR)s that make the idea of a global quantum secured network debatable. In this work, we propose a satellite assisted Key Encapsulation Mechanism (KEM) that takes advantage of the high security of a quantum AES-256-bit key encrypted link, to deliver secret keys through classical communication layer in high rates, using QKD only for link establishment. In this way, the keys produced by the QKD do not directly encrypt the data traffic, allowing therefore longer lifespans. This scheme would be able to support up to thousands terminal nodes with a total average SKR as low as 4.23 bps.