Field test of a practical secure communication network with decoy-state quantum cryptography

TL;DR

This paper demonstrates a practical secure communication network using decoy-state quantum cryptography over real-world distances, enabling real-time voice and broadcast encryption among multiple nodes.

Contribution

It presents the first real-world implementation of a decoy-state quantum cryptography network with live key exchange and application protocols over 20 km fiber links.

Findings

Successful real-time quantum key exchange among three nodes

Implementation of unbreakable voice communication using quantum keys

Real-time broadcast encryption with one-time pad

Abstract

We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption.