Long distance measurement-device-independent quantum key distribution with entangled photon sources

TL;DR

This paper introduces a practical, ultra-long-distance measurement-device-independent quantum key distribution method using entangled photon sources, enhancing security and distance capabilities in quantum communication.

Contribution

It extends MDI-QKD by incorporating entangled photon sources in the middle, enabling longer distances and robustness against detection attacks.

Findings

Can tolerate 77 dB loss over 367 km fiber in asymptotic limit

Can tolerate 60 dB loss over 286 km fiber with finite-key analysis

General model applicable to other entanglement-based quantum experiments

Abstract

We present a practical method that can make quantum key distribution (QKD), for the first time, both ultra-long-distance and immune to all attacks in the detection system. This method is an important extension of the measurement-device-independent QKD (MDI-QKD) - MDI-QKD with entangled photon sources in the middle. By proposing a general model and simulating an entanglement based QKD experiment, we find that MDI-QKD with one entangled photon source in the middle can practically tolerate 77 dB combined loss (367km standard telecom fiber) in the asymptotic limit, and it can still tolerate 60 dB combined loss (286km standard telecom fiber) in the finite-key case with state-of-the-art detectors. Our general model can also be applied to other non-QKD experiments involving entangled photon sources and Bell state measurements.