Quantum Conference Key Agreement with Photon Loss

TL;DR

This paper introduces a loss-resilient quantum conference key agreement protocol that leverages redundant encoding and error correction to improve transmission rates over existing methods, requiring high-quality photon sources.

Contribution

The paper presents a novel loss-resilient CKA protocol that outperforms previous protocols in secret key rate using photon sources with creation probability above 0.3.

Findings

Protocol achieves higher secret key rate with photon sources p > 0.3

Redundant encoding and error correction enhance loss resilience

Requires high-probability entangled photon sources for practical use

Abstract

Conference key agreement (CKA) is an information processing task where more than two parties want to share a common secret key. Here, we present a loss-resilient protocol for CKA, based on redundant encoding and error correction. Our protocol provides a speed-up in transmission rate over the existing lossy CKA protocol. However, encoding and error correction come with extra cost. We show that, using photon sources with creation probability p > 0.3, our protocol's secret key rate can overcome the existing protocol's. Hence, high probability entangled photon sources are required for realistic implementation of our loss-resilient protocol.