The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is...The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is proposed based on hyper-entangled states and Bell inequalities.The security of the protocol is analyzed against the individual attack by an adversary only limited by the no-signaling condition.Based on the formalization of Clauser-Horne Shimony-Holt(CHSH)violation measurement on local correlation,the probability of a secure secret bit is obtained,which is produced by a pair of hyper-entangled particles.By analyzing the secure secret bit,it is proven that,when both the polarization mode and the path mode contains entangled-states,the DIQKD protocol gets a better secure key rate than common Bell states.展开更多
Quantum secure direct communication(QSDC)can directly transmit secret messages through quantum channel without keys.Device-independent(DI)QSDC guarantees the message security relying only on the observation of the Bel...Quantum secure direct communication(QSDC)can directly transmit secret messages through quantum channel without keys.Device-independent(DI)QSDC guarantees the message security relying only on the observation of the Bell-inequality violation,but not on any detailed description or trust of the devices'inner workings.Compared with conventional QSDC,DI-QSDC has relatively low secret message capacity.To increase DI-QSDC's secret messages capacity,we propose a high-capacity DI-QSDC protocol based on the hyper-encoding technique.The total message leakage rate of our DI-QSDC protocol only relies on the most robust degree of freedom.We provide the numerical simulation of its secret message capacity altered with the communication distance.Our work serves as an important step toward thefurther development of DI-QSDC systems.展开更多
"Device-independent"not only represents a relaxation of the security assumptions about the internal working of the quantum devices,but also can enhance the security of the quantum communication.In the paper,..."Device-independent"not only represents a relaxation of the security assumptions about the internal working of the quantum devices,but also can enhance the security of the quantum communication.In the paper,we put forward the first device-independent quantum secure direct communication(DIQSDC)protocol and analyze its security and communication efficiency against collective attacks.Under practical noisy quantum channel condition,the photon transmission loss and photon state decoherence would reduce DI-QSDC’s communication quality and threaten its absolute security.For solving the photon transmission loss and decoherence problems,we adopt noiseless linear amplification(NLA)protocol and entanglement purification protocol(EPP)to modify the DI-QSDC protocol.With the help of the NLA and EPP,we can guarantee DI-QSDC’s absolute security and effectively improve its communication quality.展开更多
Measurement device-independent quantum key distribution(MDI-QKD) protocols are immune to all possible attacks on the photon detectors during quantum communication, but their key generation rates are low compared with ...Measurement device-independent quantum key distribution(MDI-QKD) protocols are immune to all possible attacks on the photon detectors during quantum communication, but their key generation rates are low compared with those of other QKD schemes.Increasing each individual photon’s channel capacity is an efficient way to increase the key generation rate, and high-dimensional(HD) encoding is a powerful tool for increasing the channel capacity of photons. In this paper, we propose an HD MDI-QKD protocol with qudits hyper-encoded in spatial mode and polarization degrees of freedom(DOFs). In the proposed protocol, keys can be generated using the spatial mode and polarization DOFs simultaneously. The proposed protocol is unconditionally secure,even for weak coherent pulses with decoy states. The proposed MDI-QKD protocol may be useful for future quantum secure communication applications.展开更多
Device-independent quantum secure direct communication(DI-QSDC)can relax the security assumptions about the devices’internal working,and effectively enhance QSDC’s security.In this paper,we put forward the first hyp...Device-independent quantum secure direct communication(DI-QSDC)can relax the security assumptions about the devices’internal working,and effectively enhance QSDC’s security.In this paper,we put forward the first hyperentanglement-based one-step DI-QSDC protocol.In this protocol,the communication parties adopt the nonlocal hyperentanglement-assisted complete Bell state analysis,which enables the photons to transmit in the quantum channel for only one round.The one-step DI-QSDC can directly transmit 2 bits of messages by a hyperentangled photon pair,and is unconditionally secure in theory.Compared with the original DI-QSDC protocol(Sci.Bull.65,12(2020)),the one-step DI-QSDC protocol can simplify the experiment and reduce the message loss.In particular,with the help of the hyperentanglement heralded amplification and the hyperentanglement purification,the message loss and the message error caused by the channel noise can be completely eliminated,and the communication distance can be largely extended.By using the photon source with a repetition rate of 10 GHz,the one-step DI-QSDC’s secret message capacity under 50 km communication distance achieves about 7 bit/s with the initial fidelity in each degree of freedom of 0.8.Combined with the quantum repeater,it is possible for researchers to realize the one-step DI-QSDC with an arbitrarily long distance.展开更多
Quantum entanglement,has been acknowledged as a precious resource due to its inherent nonclassical correla-tions between subsystems.These quantum correlations have the potential for many quantum processes,includ-ing c...Quantum entanglement,has been acknowledged as a precious resource due to its inherent nonclassical correla-tions between subsystems.These quantum correlations have the potential for many quantum processes,includ-ing canonical ones:quantum cryptography,quantum teleportation,and dense coding.To exploit the advantages of quantum entanglement,two essential premises are required,i.e.,to prepare high-quality entanglement and characterize quality level of prepared entanglement.Thus far,quantum entanglement can be produced in various quantum systems;however,it appears that this new resource is complex and difficult to characterize.The standard methods to characterize multipartite entanglement,e.g.,entanglement witness,state tomography,or quantum state verification,require full knowledge of the Hilbert space dimension and precise calibration of measurement devices,which are usually difficult to acquire in experiment.The most radical way to overcome these problems is to detect entanglement solely based on the Bell-like correlations of measurement outcomes collected in the exper-iment,namely,device-independent characterization of entanglement.This article reviews the recently developed device-independent methods to characterize entanglement,including self-testing and device-independent certi-fication of entanglement.These approaches can be widely applied in kinds of quantum information processing,especially for those with security demands.展开更多
基金This work is supported by NSFC(Grant Nos.61572086,61402058)the Application Foundation Project of Sichuan Province of China(Grant No.2017JY0168)+3 种基金the National Key Research and Development Program(No.2017YFB0802302)Sichuan innovation team of quantum security communication(No.17TD0009)Sichuan academic and technical leaders training funding support projects(No.2016120080102643)the Fund for Middle and Young Academic Leaders of CUIT(Grant No.J201511).
文摘The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is proposed based on hyper-entangled states and Bell inequalities.The security of the protocol is analyzed against the individual attack by an adversary only limited by the no-signaling condition.Based on the formalization of Clauser-Horne Shimony-Holt(CHSH)violation measurement on local correlation,the probability of a secure secret bit is obtained,which is produced by a pair of hyper-entangled particles.By analyzing the secure secret bit,it is proven that,when both the polarization mode and the path mode contains entangled-states,the DIQKD protocol gets a better secure key rate than common Bell states.
基金the National Natural Science Foundation of China(11974189,12175106 and 92365110)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22-0900).
文摘Quantum secure direct communication(QSDC)can directly transmit secret messages through quantum channel without keys.Device-independent(DI)QSDC guarantees the message security relying only on the observation of the Bell-inequality violation,but not on any detailed description or trust of the devices'inner workings.Compared with conventional QSDC,DI-QSDC has relatively low secret message capacity.To increase DI-QSDC's secret messages capacity,we propose a high-capacity DI-QSDC protocol based on the hyper-encoding technique.The total message leakage rate of our DI-QSDC protocol only relies on the most robust degree of freedom.We provide the numerical simulation of its secret message capacity altered with the communication distance.Our work serves as an important step toward thefurther development of DI-QSDC systems.
基金supported by the National Natural Science Foundation of China (11974189 and 11974205)the China Postdoctoral Science Foundation (2018M642293)+1 种基金the Open Research Fund of the Key Lab of Broadband Wireless Communication and Sensor Network Technology,Nanjing University of Posts and Telecommunications, Ministry of Education (JZNY201908)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘"Device-independent"not only represents a relaxation of the security assumptions about the internal working of the quantum devices,but also can enhance the security of the quantum communication.In the paper,we put forward the first device-independent quantum secure direct communication(DIQSDC)protocol and analyze its security and communication efficiency against collective attacks.Under practical noisy quantum channel condition,the photon transmission loss and photon state decoherence would reduce DI-QSDC’s communication quality and threaten its absolute security.For solving the photon transmission loss and decoherence problems,we adopt noiseless linear amplification(NLA)protocol and entanglement purification protocol(EPP)to modify the DI-QSDC protocol.With the help of the NLA and EPP,we can guarantee DI-QSDC’s absolute security and effectively improve its communication quality.
基金supported by the National Natural Science Foundation of China(Grant No.11974189)the China Postdoctoral Science Foundation(Grant No.2018M642293)+1 种基金the open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology,Nanjing University of Posts and Telecommunications,Ministry of Education(Grant No.JZNY201908)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Measurement device-independent quantum key distribution(MDI-QKD) protocols are immune to all possible attacks on the photon detectors during quantum communication, but their key generation rates are low compared with those of other QKD schemes.Increasing each individual photon’s channel capacity is an efficient way to increase the key generation rate, and high-dimensional(HD) encoding is a powerful tool for increasing the channel capacity of photons. In this paper, we propose an HD MDI-QKD protocol with qudits hyper-encoded in spatial mode and polarization degrees of freedom(DOFs). In the proposed protocol, keys can be generated using the spatial mode and polarization DOFs simultaneously. The proposed protocol is unconditionally secure,even for weak coherent pulses with decoy states. The proposed MDI-QKD protocol may be useful for future quantum secure communication applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974189,and 12175106)。
文摘Device-independent quantum secure direct communication(DI-QSDC)can relax the security assumptions about the devices’internal working,and effectively enhance QSDC’s security.In this paper,we put forward the first hyperentanglement-based one-step DI-QSDC protocol.In this protocol,the communication parties adopt the nonlocal hyperentanglement-assisted complete Bell state analysis,which enables the photons to transmit in the quantum channel for only one round.The one-step DI-QSDC can directly transmit 2 bits of messages by a hyperentangled photon pair,and is unconditionally secure in theory.Compared with the original DI-QSDC protocol(Sci.Bull.65,12(2020)),the one-step DI-QSDC protocol can simplify the experiment and reduce the message loss.In particular,with the help of the hyperentanglement heralded amplification and the hyperentanglement purification,the message loss and the message error caused by the channel noise can be completely eliminated,and the communication distance can be largely extended.By using the photon source with a repetition rate of 10 GHz,the one-step DI-QSDC’s secret message capacity under 50 km communication distance achieves about 7 bit/s with the initial fidelity in each degree of freedom of 0.8.Combined with the quantum repeater,it is possible for researchers to realize the one-step DI-QSDC with an arbitrarily long distance.
基金This work was supported by the National Key Research and Devel-opment Program of China(Nos.2016YFA0302700,2017YFA0304100)National Natural Science Foundation of China(Grant Nos.11874344,61835004,11774335,91536219,11821404)+3 种基金Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSW-SLH003)Anhui Initiative in Quantum Information Technologies(AHY020100,AHY060300)the Fundamental Research Funds for the Central Universities(Grant no.WK2030020019,WK2470000026)Science Foundation of the CAS(No.ZDRW-XH-2019-1).
文摘Quantum entanglement,has been acknowledged as a precious resource due to its inherent nonclassical correla-tions between subsystems.These quantum correlations have the potential for many quantum processes,includ-ing canonical ones:quantum cryptography,quantum teleportation,and dense coding.To exploit the advantages of quantum entanglement,two essential premises are required,i.e.,to prepare high-quality entanglement and characterize quality level of prepared entanglement.Thus far,quantum entanglement can be produced in various quantum systems;however,it appears that this new resource is complex and difficult to characterize.The standard methods to characterize multipartite entanglement,e.g.,entanglement witness,state tomography,or quantum state verification,require full knowledge of the Hilbert space dimension and precise calibration of measurement devices,which are usually difficult to acquire in experiment.The most radical way to overcome these problems is to detect entanglement solely based on the Bell-like correlations of measurement outcomes collected in the exper-iment,namely,device-independent characterization of entanglement.This article reviews the recently developed device-independent methods to characterize entanglement,including self-testing and device-independent certi-fication of entanglement.These approaches can be widely applied in kinds of quantum information processing,especially for those with security demands.
