Improved Eavesdropping Detection Strategy in Quantum Direct Communication Protocol Based on Four-particle GHZ State

TL;DR

This paper proposes an improved eavesdropping detection method in quantum direct communication using four-particle GHZ states, significantly increasing detection efficiency and security compared to previous strategies.

Contribution

The paper introduces a novel detection strategy employing four-particle GHZ states and entropy theory, enhancing eavesdropper detection rate from 50% to 88%.

Findings

Detection rate increased from 50% to 88%.

The proposed method is more secure against eavesdroppers.

Entropy theory effectively compares detection strategies.

Abstract

In order to improve the eavesdropping detection efficiency in two-step quantum direct communication protocol, an improved eavesdropping detection strategy using four-particle GHZ state is proposed, in which four-particle GHZ state is used to detect eavesdroppers. During the security analysis, the method of the entropy theory is introduced, and two detection strategies are compared quantitatively by using the constraint between the information which eavesdropper can obtain and the interference introduced. If the eavesdroppers intend to obtain all information, the eavesdropping detection rate of the original two-step quantum direct communication protocol by using EPR pair block as detection particles is 50%; while the proposed strategy's detection rate is 88%. In the end, the security of the proposed protocol is discussed. The analysis results show that the eavesdropping detection strategy presented is more secure.