Practical Scheme To Share A Secret Key Through An Up To 27.6% Bit Error Rate Quantum Channel

TL;DR

This paper presents a practical quantum key distribution scheme that remains secure and effective even when the quantum channel error rate is as high as approximately 27.6%, significantly improving error tolerance.

Contribution

The paper introduces an adaptive privacy amplification method with two-way communication, achieving the highest known error threshold for secure quantum key distribution.

Findings

Secure key generation up to 27.6% error rate

Implementation of adaptive privacy amplification

Enhanced robustness against channel noise

Abstract

A secret key shared through quantum key distribution between two cooperative players is secure against any eavesdropping attack allowed by the laws of physics. Yet, such a key can be established only when the quantum channel error rate due to eavesdropping or imperfect apparatus is low. Here, I report a practical quantum key distribution scheme making use of an adaptive privacy amplification procedure with two-way classical communication. Then, I prove that the scheme generates a secret key whenever the bit error rate of the quantum channel is less than $0.5-0.1\sqrt{5} \approx 27.6%$, thereby making it the most error resistant scheme known to date.