Unconditionally secure quantum key-distribution with relatively strong signal pulse

TL;DR

This paper introduces a secure quantum key distribution protocol using strong signal pulses, reducing detector requirements and enhancing robustness against scattering, enabling longer-distance secure communication.

Contribution

It presents a novel QKD scheme that uses fewer detectors and is resilient to Rayleigh scattering, with a derived secret key rate bound for long-distance applications.

Findings

Protocol is robust against Rayleigh scattering.

Can achieve secure communication over longer distances.

Reduces detector count compared to similar protocols.

Abstract

We propose an unconditionally secure quantum key distribution (QKD) protocol, which uses a relatively strong signal pulse. While our protocol shares similar security bases as the Bennett 1992 protocol with a strong reference pulse (B92), our scheme uses a smaller number of detectors and it is robust against Rayleigh scattering in an optical fibre. We derive a lower bound of secret key generation rate of our protocol and show that our protocol can cover relatively long distances, assuming precise phase modulations and stable interferometers.