Multi-partite entanglement speeds up quantum key distribution in networks

TL;DR

This paper demonstrates that using genuine N-partite entanglement in quantum networks enhances conference key distribution by increasing secret key rates and efficiency, especially in networks with bottlenecks, compared to bipartite methods.

Contribution

It introduces a protocol utilizing N-partite entanglement for conference key distribution and compares its efficiency and resource requirements to bipartite methods, highlighting advantages in network coding scenarios.

Findings

Multipartite entanglement improves secret key rates.

The protocol outperforms bipartite schemes in network bottleneck situations.

Higher threshold qubit error rates are achievable with multipartite entanglement.

Abstract

The laws of quantum mechanics allow for the distribution of a secret random key between two parties. Here we analyse the security of a protocol for establishing a common secret key between N parties (i.e. a conference key), using resource states with genuine N-partite entanglement. We compare this protocol to conference key distribution via bipartite entanglement, regarding the required resources, achievable secret key rates and threshold qubit error rates. Furthermore we discuss quantum networks with bottlenecks for which our multipartite entanglement-based protocol can benefit from network coding, while the bipartite protocol cannot. It is shown how this advantage leads to a higher secret key rate.