Decoy state measurement-device-independent quantum key distribution based on the Clauser-Horne-Shimony-Holt inequality

TL;DR

This paper presents a practical decoy-state CHSH-MDI-QKD protocol that enhances security by relaxing device assumptions and considers finite-size effects, demonstrating its feasibility through simulations.

Contribution

It introduces a decoy-state CHSH-MDI-QKD protocol with multiple intensities and analyzes its finite-size effects, advancing secure quantum communication methods.

Findings

Protocol is practical with multiple intensities.

Finite-size effects are effectively managed.

Simulation confirms protocol's feasibility.

Abstract

The measurement-device-independent quantum key distribution (MDI-QKD) protocol is proposed to remove the detector side channel attacks, while its security relies on the assumption that the encoding systems are perfectly characterized. In contrast, the MDI-QKD protocol based on the Clauser-Horne-Shimony-Holt inequality (CHSH-MDI-QKD) weakens this assumption, which only requires the quantum state to be prepared in the two-dimensional Hilbert space and the devices are independent. In experimental realizations, the weak coherent state, which is always used in QKD systems due to the lack of an ideal single photon source, may be prepared in the high-dimensional space. In this paper, we investigate the decoy-state CHSH-MDI-QKD protocol with $s(3 \le s \le 5)$ intensities, including one signal state and $s-1$ decoy states, and we also consider the finite-size effect on the decoy-state CHSH-MDI-QKD protocol with five intensities. Simulation results show that this scheme is very practical.