Multidimensional reconciliation for continuous-variable quantum key distribution

TL;DR

This paper introduces an eight-dimensional reconciliation method using octonions for continuous-variable quantum key distribution, enabling secure key extraction over longer distances without postselection.

Contribution

The paper presents a novel eight-dimensional reconciliation scheme based on octonions that improves the security and range of continuous-variable quantum key distribution.

Findings

Secure key distribution distance is significantly extended.

The method is secure against arbitrary collective attacks.

No postselection is required in the protocol.

Abstract

We propose a method for extracting an errorless secret key in a continuous-variable quantum key distribution protocol, which is based on Gaussian modulation of coherent states and homodyne detection. The crucial feature is an eight-dimensional reconciliation method, based on the algebraic properties of octonions. Since the protocol does not use any postselection, it can be proven secure against arbitrary collective attacks, by using well-established theorems on the optimality of Gaussian attacks. By using this new coding scheme with an appropriate signal to noise ratio, the distance for secure continuous-variable quantum key distribution can be significantly extended.