Prefixed-threshold Real-Time Selection for Free-Space Measurement-Device-Independent Quantum Key Distribution
Abstract
Measurement-Device-Independent (MDI) QKD eliminates detector side channels in QKD and allows an untrusted relay between two users. A desirable yet highly challenging application is to implement MDI-QKD through free-space channels. One of the major factors that affect the secure key rate in free-space MDI-QKD is atmospheric turbulence. In this work we show two important results: First, the independent fluctuations of transmittances in the two channels can significantly reduce MDI-QKD performance due to turbulence-induced channel asymmetry. Second, we consider the Prefixed Real-Time Selection (P-RTS) method we formerly introduced to BB84 and extend it to MDI-QKD. Users can monitor classical transmittances in their channels and improve performance by post-selecting signals in real-time based on pre-calculated thresholds. We show that we can establish a 2-dimensional threshold between Alice and Bob to post-select signals with both high signal-to-noise ratio and low channel asymmetry in real time, and greatly extend the maximum range of MDI-QKD in the presence of turbulence, which can be an important step towards future free-space MDI-QKD experiments.
Keywords
Cite
@article{arxiv.1910.10137,
title = {Prefixed-threshold Real-Time Selection for Free-Space Measurement-Device-Independent Quantum Key Distribution},
author = {Wenyuan Wang and Feihu Xu and Hoi-Kwong Lo},
journal= {arXiv preprint arXiv:1910.10137},
year = {2019}
}
Comments
This is a draft version of the manuscript submitted to QCrypt 2019 on April 10th, and presented as a poster on August 26th. We are still working on more results based on finite-size scenario and will later update the manuscript when finished