Error estimation at the information reconciliation stage of quantum key distribution

TL;DR

This paper introduces a new syndrome-based algorithm for more accurate quantum bit error rate estimation during the information reconciliation phase of quantum key distribution, improving security and efficiency.

Contribution

It presents a novel QBER estimation algorithm tailored for irregular LDPC codes that enhances accuracy in practical QKD systems.

Findings

Improved QBER estimation accuracy in real QKD setups

Effective handling of punctured and shortened bits in LDPC codes

Enhanced security and efficiency in quantum key distribution

Abstract

Quantum key distribution (QKD) offers a practical solution for secure communication between two distinct parties via a quantum channel and an authentic public channel. In this work, we consider different approaches to the quantum bit error rate (QBER) estimation at the information reconciliation stage of the post-processing procedure. For reconciliation schemes employing low-density parity-check (LDPC) codes, we develop a novel syndrome-based QBER estimation algorithm. The algorithm suggested is suitable for irregular LDPC codes and takes into account punctured and shortened bits. Testing our approach in a real QKD setup, we show that an approach combining the proposed algorithm with conventional QBER estimation techniques allows one to improve the accuracy of the QBER estimation.