Quantum secure direct communication with entanglement source and single-photon measurement

作者：Lu Yang,JiaWei Wu,ZaiSheng Lin,LiuGuo Yin,GuiLu Long

摘要：Quantum secure direct communication(QSDC)transmits information directly over a quantum channel.In addition to security in transmission,it avoids loopholes of key loss and prevents the eavesdropper from getting ciphertext.In this article,we propose a QSDC protocol using entangled photon pairs.This protocol differs from existing entanglement-based QSDC protocols because it does not perform Bell-state measurement,and one photon of the entangled pair is measured after the entanglement distribution.It has the advantage of high signal-to-noise ratio due to the heralding function of entanglement pairs,and it also has the relative ease in performing single-photon measurement.The protocol can use a practical entanglement source from spontaneous parametric down-conversion(SPDC);Gottesman-Lo-Lu¨tkenhaus-Preskill theory and the decoy state method give a better estimate of the error rate.Security analysis is completed with Wyner’s wiretap channel theory,and the lower bound of the secrecy capacity is estimated.Numerical simulations were carried out to study the performance of the protocol.These simulations demonstrated that the protocol with a practical SPDC entanglement source performed well and was close to the case with an ideal entanglement source.

发文机构：State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Frontier Science Center for Quantum Information School of Information and Technology Beijing National Research Center for Information Science and Technology Beijing Academy of Quantum Information Sciences

关键词：quantumsecuredirectcommunicationquantumsecurecommunicationquantumcommunicationquantuminformation

分类号： O413[理学—理论物理]TN918[理学—物理]