The Security of Quantum Key Distribution using a Simplified Trusted Relay

TL;DR

This paper introduces a simplified quantum key distribution protocol for trusted relays that reallocates classical post-processing tasks to end users, maintaining quantum signal exchange and ensuring security with decoy analysis.

Contribution

It presents a novel QKD protocol that shifts classical processing to users and provides a security analysis based on BB84 with decoy states.

Findings

Protocol maintains security with weak coherent sources.

Reassigns classical tasks to end users, simplifying relay operations.

Security verified through infinite key analysis.

Abstract

We propose a QKD protocol for trusted node relays. Our protocol shifts the communication and computational weight of classical post-processing to the end users by reassigning the roles of error correction and privacy amplification, while leaving the exchange of quantum signals untouched. We perform a security analysis for this protocol based on the BB84 protocol on the level of infinite key formulas, taking into account weak coherent implementations involving decoy analysis.