Z. Naturforsch. 67a, 369 – 376
(2012)
doi:10.5560/ZNA.2012-0029
Improved Security Detection Strategy in Quantum Secure Direct Communication Protocol Based on Four-Particle Green–Horne–Zeilinger State
Jian
Li1,
Jin-Rui
Nie1,
Rui-Fan
Li1, and
Bo
Jing1,2
1 School of Computer, Beijing University of Posts and Telecommunications, Beijing 100876, P. R. China
2 Department of Computer Science, Beijing Institute of Applied Meteorology, Beijing 100029, P. R. China
Received October 6, 2011 / revised February 16, 2012 / published online July 3, 2012
To enhance the efficiency of eavesdropping detection in the quantum secure direct communication protocol, an improved quantum secure direct communication protocol based on a four-particle Green–Horne–Zeilinger (GHZ) state is presented. In the protocol, the four-particle GHZ state is used to detect eavesdroppers, and quantum dense coding is used to encode the message. In the security analysis, the method of entropy theory is introduced, and two detection strategies are compared quantitatively by using the constraint between the information that the eavesdroppers can obtain and the interference that has been introduced. If the eavesdropper wants to obtain all the information, the detection rate of the quantum secure direct communication using an Einstein–Podolsky–Rosen (EPR) pair block will be 50% and the detection rate of the presented protocol will be 87%. At last, the security of the proposed protocol
is discussed. The analysis results indicate that the protocol proposed is more secure than the others.
Key words: Quantum Secure Direct Communication Protocol; Dense Coding; Four-Particle GHZ State; Eavesdropping Detection.