In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 200...In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 2002, 89： 187902]. But the protocol was proved very vulnerable, and can be attacked by an eavesdropper. An improved ＂Ping-pong＂ protocol is presented to overcome the problem. The GHZ state particles are used to detect eavesdroppers, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information which an eavesdropper can obtain and the interference introduced. If the eavesdropper gets the full information, the detection rate of the original ＂Ping-pong＂ protocol is 50%; the detection rate of the second protocol which used two particles of EPR pair as detection particles is also 50%; and the detection rate of the presented protocol is 75%. In the end, the security of the pro-posed protocol is discussed. The analysis results show that the improved ＂Ping-pong＂ protocol in this paper is more secure than the other two.展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060013007)the Natural Science Foundation of Beijing (Grant No. 4092029)the National Natural Science Foundation of China (Grant No. 60873001)
文摘In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called ＂Ping-pong＂ protocol was proposed by Bostrrm and Felbinger [Bostrom K, et al. Phys Rev Lett, 2002, 89： 187902]. But the protocol was proved very vulnerable, and can be attacked by an eavesdropper. An improved ＂Ping-pong＂ protocol is presented to overcome the problem. The GHZ state particles are used to detect eavesdroppers, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information which an eavesdropper can obtain and the interference introduced. If the eavesdropper gets the full information, the detection rate of the original ＂Ping-pong＂ protocol is 50%; the detection rate of the second protocol which used two particles of EPR pair as detection particles is also 50%; and the detection rate of the presented protocol is 75%. In the end, the security of the pro-posed protocol is discussed. The analysis results show that the improved ＂Ping-pong＂ protocol in this paper is more secure than the other two.
