Reconciliation of a Quantum-Distributed Gaussian Key

TL;DR

This paper introduces a new method for Alice and Bob to reconcile correlated Gaussian variables into identical binary keys with minimal information leakage, enhancing continuous-variable quantum key distribution security.

Contribution

It presents a novel classical reconciliation technique tailored for Gaussian variables in quantum key distribution, reducing information leakage during key correction.

Findings

Effective reconciliation of Gaussian variables into binary keys.

Minimal leaked information during the correction process.

Applicable to recent continuous-variable QKD protocols.

Abstract

Two parties, Alice and Bob, wish to distill a binary secret key out of a list of correlated variables that they share after running a quantum key distribution protocol based on continuous-spectrum quantum carriers. We present a novel construction that allows the legitimate parties to get equal bit strings out of correlated variables by using a classical channel, with as few leaked information as possible. This opens the way to securely correcting non-binary key elements. In particular, the construction is refined to the case of Gaussian variables as it applies directly to recent continuous-variable protocols for quantum key distribution.