Fully Passive Quantum Conference Key Agreement

TL;DR

This paper introduces a fully passive, interference-based quantum conference key agreement protocol that enhances security and performance for multi-party quantum communication.

Contribution

It extends the fully passive approach to quantum conference key agreement, improving security and robustness against side channels in multi-user settings.

Findings

Achieves measurement-device-independence and high key rates in high-loss channels.

Eliminates source modulation side channels through a fully passive design.

Enhances implementation security for many-user quantum communication.

Abstract

Quantum Conference Key Agreement (CKA) provides a secure method for multi-party communication. A recently developed interference-based prepare-and-measure quantum CKA possesses the advantages of measurement-device-independence, namely, being immune to side-channels from the detector side. Besides, it achieves good key rate performance, especially for high-loss channels, due to the use of single photon interference. Meanwhile, several fully passive QKD schemes have been proposed, which eliminate all side channels from the source modulation side. We extend the fully passive idea to an interference-based CKA, which has a high level of implementation security for many-user communication.