Long-Distance Device-Independent Conference Key Agreement

TL;DR

This paper introduces a new device-independent conference key agreement protocol that employs heralding to distribute multipartite entanglement, significantly improving key rates despite losses, and demonstrating advantages over previous protocols with feasible measurements.

Contribution

The paper proposes a heralding-based DI-CKA protocol that enhances key distribution performance under realistic loss conditions, advancing practical quantum network security.

Findings

Protocol outperforms previous DI-CKA schemes in key rate.

Heralding scheme effectively mitigates loss limitations.

Experimental feasibility demonstrated with current measurement technology.

Abstract

Device-independent quantum key distribution (DI-QKD) enables two remote parties to share an information-theoretically secure key without any assumptions on the inner workings of the devices used. Device-independent conference key agreement (DI-CKA) is multipartite DI-QKD where more than two parties share a common secure key. The performance of DI-CKA, however, is strictly limited because of its susceptibility to losses due e.g. to imperfect detection efficiency and channel transmission. Here, we propose a DI-CKA protocol which reduces this limitation by using a heralding scheme to distribute multipartite entanglement. We analyze key rates of our protocol for two different measurement scenarios and we show that our protocol outperforms a previous DI-CKA protocol even with an experimentally feasible measurement.