Preparing a commercial quantum key distribution system for certification against implementation loopholes

TL;DR

This paper prepares a fiber-optic QKD system for certification by analyzing and addressing known and potential implementation loopholes, ensuring robustness for secure quantum communication deployment.

Contribution

It provides a detailed hardware and post-processing analysis of a QKD system, identifies loopholes, and implements design modifications for certification readiness.

Findings

Hardware analyzed for known loopholes

System design amended to mitigate high-risk loopholes

Guidelines outlined for certification lab requirements

Abstract

A commercial quantum key distribution (QKD) system needs to be formally certified to enable its wide deployment. The certification should include the system's robustness against known implementation loopholes and attacks that exploit them. Here we ready a fiber-optic QKD system for this procedure. The system has a prepare-and-measure scheme with decoy-state BB84 protocol, polarisation encoding, qubit source rate of 312.5 MHz, and is manufactured by QRate. We detail its hardware and post-processing. We analyse the hardware for known implementation loopholes, search for possible new loopholes, and discuss countermeasures. We then amend the system design to address the highest-risk loopholes identified. We also work out technical requirements on the certification lab and outline its possible structure.