Asynchronous QKD on a Relay Network

TL;DR

This paper presents a method for asynchronous quantum key distribution over a relay network, ensuring security even if some relays are compromised, by using bit-transport and secret-sharing techniques.

Contribution

It introduces an adapted secret-sharing scheme enabling secure asynchronous QKD on multi-user relay networks, requiring trust in only one relay for security.

Findings

Secure key establishment between users with relay compromise resistance

Use of bit-transport technique for asynchronous QKD

Trust in at least one relay suffices for security

Abstract

We show how QKD on a multi-user, multi-path, network can be used to establish a key between any two end users in an asynchronous fashion using the technique of bit-transport. By a suitable adaptation of our previous secret-sharing scheme we show that an attacker has to compromise all of the intermediate relays on the network in order to obtain the key. Thus, two end users can establish a secret key provided they trust at least one of the network relays.