Quantum communications helps us to enhance the security and efficiency of communications and to deepen our understanding of quantum physics. Its rapid development in recent years has attracted the interest of research...Quantum communications helps us to enhance the security and efficiency of communications and to deepen our understanding of quantum physics. Its rapid development in recent years has attracted the interest of researchers from diverse fields such as physics, mathematics, and computer science. We review the background and current state of quantum communications technology, with an emphasis on quantum key distribution, quantum random number generation, and a relatively hot topic: device independent protocols.展开更多
In polarization-encoded free-space quantum communications, a transmitter on a satellite and a receiver in a ground station each have a respective polarization zero direction, by which they encode and decode every pola...In polarization-encoded free-space quantum communications, a transmitter on a satellite and a receiver in a ground station each have a respective polarization zero direction, by which they encode and decode every polariza-tion quantum bit required for a quantum com-munication protocol. In order to complete the protocol, the ground-based receiver needs to track and compensate for the polarization zero direction of the satellite-based transmitter. Ex- pressions satisfied by amplitudes of the s-polarization component and the p-polarization component are derived based on a two-mirror model, and a condition satisfied by the reflec- tion coefficients of the two mirrors is given. A polarization tracking principle is analyzed for satellite-to-ground quanaun communications, and quantum key encoding and decoding prin- ciples based on polarization tracking are given. A half-wave-plate-based dynamic polariza- tion-basis compensation scheme is proposed in this paper, and this scheme is proved to be suitable for satellite-to-ground and intersatellite quantum communications.展开更多
Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high...Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum communications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks.展开更多
his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issu...his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issue comprises four papers on recent advances in physical layer security forwireless networks. The second Part comprises another four papers on quantum com- munications.展开更多
Hardly had the elation in the wake of the 1,200 km-survival of quantum entanglement subsided before we again had news from Micius.On August 10,the joint team reported online in Nature the results from the other two ma...Hardly had the elation in the wake of the 1,200 km-survival of quantum entanglement subsided before we again had news from Micius.On August 10,the joint team reported online in Nature the results from the other two major experiments aboard the satellite:Both the encrypted quantum key distribution(QKD)and quantum teleportation(QT)successfully passed through a distance of approximately 1,200 km,and did so less展开更多
As the first stage of the quantum Internet,quantum key distribution(QKD)networks hold the promise of providing long-term security for diverse users.Most existing QKD networks have been constructed based on independent...As the first stage of the quantum Internet,quantum key distribution(QKD)networks hold the promise of providing long-term security for diverse users.Most existing QKD networks have been constructed based on independent QKD protocols,and they commonly rely on the deployment of single-protocol trusted relay chains for long reach.Driven by the evolution of QKD protocols,large-scale QKD networking is expected to migrate from a single-protocol to a multi-protocol paradigm,during which some useful evolutionary elements for the later stages of the quantum Internet may be incorporated.In this work,we delve into a pivotal technique for large-scale QKD networking,namely,multi-protocol relay chaining.A multi-protocol relay chain is established by connecting a set of trusted/untrusted relays relying on multiple QKD protocols between a pair of QKD nodes.The structures of diverse multi-protocol relay chains are described,based on which the associated model is formulated and the policies are defined for the deployment of multi-protocol relay chains.Furthermore,we propose three multi-protocol relay chaining heuristics.Numerical simulations indicate that the designed heuristics can effectively reduce the number of trusted relays deployed and enhance the average security level versus the commonly used single-protocol trusted relay chaining methods on backbone network topologies.展开更多
We propose a quantum multiple access communications scheme using Orbital Angular Momentum (OAM) sector states in the paper. In the scheme, each user has an individual modified Poincare Bloch sphere and encodes his inf...We propose a quantum multiple access communications scheme using Orbital Angular Momentum (OAM) sector states in the paper. In the scheme, each user has an individual modified Poincare Bloch sphere and encodes his information with his own corresponding sector OAM states. A prepared entangled photon pairs are separated at transmitter and receiver. At the transmitter, each user encodes his information with the sector OAM states on the photons and the superposition of the different sector OAM states is carried by the photons. Then the photons are transmitted through quantum noiseless channel to the receiver. At the receiver, each user could retrieve his information by coincidently measuring the transmitted photons with the receiver side photons which are modulated by a special prepared measurement basis. The theoretical analysis and the numerical simulations show that each user could get his information from the superposition state without error. It seems that this scheme provides a novel method for quantum multiple users communications.展开更多
We present error-rejecting entanglement concentration protocols(ECPs)for partially entangled electron spins in quantum dots(QDs)with unknown and known parameters using quantum electrodynamics of QDs coupled with optic...We present error-rejecting entanglement concentration protocols(ECPs)for partially entangled electron spins in quantum dots(QDs)with unknown and known parameters using quantum electrodynamics of QDs coupled with optical cavities,which can recover the partially entangled state to the maximally entangled state with unit fidelity even in the non-ideal experimental condition.The error-rejecting ECP for a partially entangled state utilizes parity check operations on electron spins within QDs.Furthermore,for a partially entangled state with known parameters,the ECP is devised through a parameter-splitting approach.The success probabilities of these two error-rejecting ECPs can be further improved by using the resource recycling method and iteration method.On account of their unit fidelity and considerable success probability,the error-rejecting ECPs have promising application value in improving the fidelity of quantum communication.展开更多
Quantum communication networks,such as quantum key distribution(QKD)networks,typically employ the measurement-resend mechanism between two users using quantum communication devices based on different quantum encoding ...Quantum communication networks,such as quantum key distribution(QKD)networks,typically employ the measurement-resend mechanism between two users using quantum communication devices based on different quantum encoding types.To achieve direct communication between the devices with different quantum encoding types,in this paper,we propose encoding conversion schemes between the polarization bases(rectilinear,diagonal and circular bases)and the time-bin phase bases(two phase bases and time-bin basis)and design the quantum encoding converters.The theoretical analysis of the encoding conversion schemes is given in detail,and the basis correspondence of encoding conversion and the property of bit flip are revealed.The conversion relationship between polarization bases and time-bin phase bases can be easily selected by controlling a phase shifter.Since no optical switches are used in our scheme,the converter can be operated with high speed.The converters can also be modularized,which may be utilized to realize miniaturization in the future.展开更多
Quantum secure direct communication(QSDC) is a communication method based on quantum mechanics and it is used to transmit secret messages. Unlike quantum key distribution, secret messages can be transmitted directly o...Quantum secure direct communication(QSDC) is a communication method based on quantum mechanics and it is used to transmit secret messages. Unlike quantum key distribution, secret messages can be transmitted directly on a quantum channel with QSDC. Higher channel capacity and noise suppression capabilities are key to achieving longdistance quantum communication. Here, we report a continuous-variable QSDC scheme based on mask-coding and orbital angular momentum, in which the mask-coding is employed to protect the security of the transmitting messages and to suppress the influence of excess noise. The combination of orbital angular momentum and information block transmission effectively improves the secrecy capacity. In the 800 information blocks ×1310 bits length 10-km experiment, the results show a statistical average bit error rate of 0.38%, a system excess noise value of 0.0184 SNU, and a final secrecy capacity of 6.319×10~6 bps. Therefore, this scheme reduces error bits while increasing secrecy capacity, providing a solution for long-distance large-scale quantum communication, which is capable of transmitting text, images and other information of reasonable size.展开更多
Continuous-variable quantum secure direct communication(CVQSDC)with Gaussian modulation(GM)demands a considerable quantity of random numbers during the preparation process and encodes them separately on the quadrature...Continuous-variable quantum secure direct communication(CVQSDC)with Gaussian modulation(GM)demands a considerable quantity of random numbers during the preparation process and encodes them separately on the quadrature components of the quantum states.Hence,high-speed random number generators are required to satisfy this demand,which is difficult to implement in practical applications.CVQSDC with discrete modulation(DM),correspondingly,employs a finite number of quantum states to achieve encoding,which can circumvent the shortcomings of the GM scheme.Based on the advantages of DM,the issue of attaining the most optimal secrecy capacity and communication distance remains to be resolved.Here,we propose a CVQSDC protocol based on N-symbol amplitude phase shift keying(N-APSK),which exploits the Boltzmann-Maxwell distribution assisted probability shaping technique.In comparison with the uniform distribution,according to 32-APSK CVQSDC,the proposed scheme extends the communication distance by about 38%,while obtaining a higher secrecy capacity at the same communication distance.Furthermore,increasing the value of N will concurrently increase the quantity of rings in the constellation,thereby facilitating enhancements of communication distance.This work incorporates the modulation approaches prevalently employed in classical communication into the realm of quantum communication,attaining gratifying advancements in communication distance and secrecy capacity,and concurrently facilitating the integrated development of quantum communication and classical communication.展开更多
Based on mutual authentication and dense coding,a novel revised efficient quantum direct communication scheme is proposed.It is composed of two phases：the quantum state distribution process and the direct communicati...Based on mutual authentication and dense coding,a novel revised efficient quantum direct communication scheme is proposed.It is composed of two phases：the quantum state distribution process and the direct communication process.The purpose of the former is to authenticate Trent and users to each other,and let the two legitimate users（Alice and Bob）safely share the Bell states.While the latter aims to make direct communication to transmit a secret message between Alice and Bob.In order to prevent from Eve＇s eavesdropping as well as to authenticate each other simultaneously,a decoy photon checking technique is applied.Compared with other analogous protocols,the quantum state distribution process is more simple and feasible and the proposed scheme is more efficient;i.e.,the total efficiency is almost 100%.Security analysis shows that the proposed scheme is secure against the eavesdropping attacks,the impersonation attacks,and some special Trent＇s attacks,including the attacks by using different initial states.展开更多
Trusted relays are the main state-of-the-art way to realize quantum key distribution networks.However,it is hard to require that all nodes in the network are fully trusted.In a multipath keytransmission mechanism,the ...Trusted relays are the main state-of-the-art way to realize quantum key distribution networks.However,it is hard to require that all nodes in the network are fully trusted.In a multipath keytransmission mechanism,the nodes can be weakly trusted because the secret key can be split into many parts and each part is transmitted to the receiver through a different path.However,if the capacity of a node’s quantum key pool is poorly designed,an attacker,Eve may eavesdrop on the communicating parties’secret message by initiating a redirection attack.In this paper,we show that Eve can trigger a cascading collapse effect by collapsing one of the edges in the network and forcing the communication parties to transmit the message through the nodes controlled by Eve.The influence of the traffic transfer ratio and the control parameters of the edge load on the breakdown probability of the edge are analyzed using a simulation.In order to effectively defend against the cascading attack,it is important for the designer to handle the relationship between the traffic and the capacity of the quantum key pool of each node in the network.展开更多
With ensured network connectivity in quantum channels, the issue of distributing entangled particles in wireless quantum communication mesh networks can be equivalently regarded as a problem of quantum backbone nodes ...With ensured network connectivity in quantum channels, the issue of distributing entangled particles in wireless quantum communication mesh networks can be equivalently regarded as a problem of quantum backbone nodes selection in order to save cost and reduce complexity. A minimum spanning tree（ MST）-based quantum distribution algorithm（ QDMST） is presented to construct the mesh backbone network. First, the articulation points are found,and for each connected block uncovered by the articulation points, the general centers are solved. Then, both articulation points and general centers are classified as backbone nodes and an M ST is formed. The quantum path between every two neighbor nodes on the MST is calculated. The nodes on these paths are also classified as backbone nodes. Simulation results validate the advantages of QDMST in the average backbone nodes number and average quantum channel distance compared to the existing random selection algorithm under multiple network scenarios.展开更多
On basis of the nonlocality without entanglement proposed by Bennett,the properties of an orthogonal set of product states of two qutrits are revealed,i.e.,the transformation among different composite spaces can be re...On basis of the nonlocality without entanglement proposed by Bennett,the properties of an orthogonal set of product states of two qutrits are revealed,i.e.,the transformation among different composite spaces can be realized by using three unitary operations,and the correlation between two composite spaces is found.These properties can be used to quantum communication and quantum cryptography.As examples,we propose a scheme of controlled quantum secure direct communication and one of quantum key distribution.It is shown that applying the product state of qutrit to quantum information processing not only is of the advantages of large capacity and high efficiency,but ensures the security.展开更多
This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and de...This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.展开更多
We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdroppe...We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdropper, Eve, intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in the same state, and measures the returned photons with the measuring basis, with which Eve prepares the fake signal except for one photon. This attack increases neither the quantum channel losses nor the error rate in the sampling instances for eavesdropping check. It works for eavesdropping the secret message transmitted with the ping-pong protocol. Finally, we propose a way for improving the security of the ping-pong protocol.展开更多
Wireless quantum communication networks transfer quantum state by teleportation. Existing research focuses on maximal entangled pairs. In this paper, we analyse the distributed wireless quantum communication networks ...Wireless quantum communication networks transfer quantum state by teleportation. Existing research focuses on maximal entangled pairs. In this paper, we analyse the distributed wireless quantum communication networks with partially entangled pairs. A quantum routing scheme with multi-hop teleportation is proposed. With the proposed scheme, is not necessary for the quantum path to be consistent with the classical path. The quantum path and its associated classical path are established in a distributed way. Direct multi-hop teleportation is conducted on the selected path to transfer a quantum state from the source to the destination. Based on the feature of multi-hop teleportation using partially entangled pairs, if the node number of the quantum path is even, the destination node will add another teleportation at itself. We simulated the performance of distributed wireless quantum communication networks with a partially entangled state. The probability of transferring the quantum state successfully is statistically analyzed. Our work shows that multi-hop teleportation on distributed wireless quantum networks with partially entangled pairs is feasible.展开更多
We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced wi...We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol.展开更多
A novel efficient deterministic secure quantum communication scheme based on four-qubit cluster states and single-photon identity authentication is proposed. In this scheme, the two authenticated users can transmit tw...A novel efficient deterministic secure quantum communication scheme based on four-qubit cluster states and single-photon identity authentication is proposed. In this scheme, the two authenticated users can transmit two bits of classical information per cluster state, and its efficiency of the quantum communication is 1/3, which is approximately 1.67 times that of the previous protocol presented by Wang et al [Chin. Phys. Lett. 23 （2006） 2658]. Security analysis shows the present scheme is secure against intercept-resend attack and the impersonator＇s attack. Furthermore, it is more economic with present-day techniques and easily processed by a one-way quantum computer.展开更多
基金supported by the National Basic Research Program of China under Grants No. 2011CBA00200 No. 2011CB921200+2 种基金National Natural Science Foundation of China under Grants No. 60921091 No. 61101137 No. 61201239
文摘Quantum communications helps us to enhance the security and efficiency of communications and to deepen our understanding of quantum physics. Its rapid development in recent years has attracted the interest of researchers from diverse fields such as physics, mathematics, and computer science. We review the background and current state of quantum communications technology, with an emphasis on quantum key distribution, quantum random number generation, and a relatively hot topic: device independent protocols.
基金supported by the Scientific Research Fund of Heilongjiang Provincial Education Department of China under Grant No.12511119
文摘In polarization-encoded free-space quantum communications, a transmitter on a satellite and a receiver in a ground station each have a respective polarization zero direction, by which they encode and decode every polariza-tion quantum bit required for a quantum com-munication protocol. In order to complete the protocol, the ground-based receiver needs to track and compensate for the polarization zero direction of the satellite-based transmitter. Ex- pressions satisfied by amplitudes of the s-polarization component and the p-polarization component are derived based on a two-mirror model, and a condition satisfied by the reflec- tion coefficients of the two mirrors is given. A polarization tracking principle is analyzed for satellite-to-ground quanaun communications, and quantum key encoding and decoding prin- ciples based on polarization tracking are given. A half-wave-plate-based dynamic polariza- tion-basis compensation scheme is proposed in this paper, and this scheme is proved to be suitable for satellite-to-ground and intersatellite quantum communications.
基金support from the Natural Science Foundation of China(61975001)National Key R&D Program of China(2018YFB1107205)+1 种基金Beijing Natural Science Foundation(Z190005)the Key R&D Program of Guangdong Province(2018B030329001).
文摘Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum communications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks.
文摘his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issue comprises four papers on recent advances in physical layer security forwireless networks. The second Part comprises another four papers on quantum com- munications.
文摘Hardly had the elation in the wake of the 1,200 km-survival of quantum entanglement subsided before we again had news from Micius.On August 10,the joint team reported online in Nature the results from the other two major experiments aboard the satellite:Both the encrypted quantum key distribution(QKD)and quantum teleportation(QT)successfully passed through a distance of approximately 1,200 km,and did so less
基金supported in part by the National Natural Science Foundation of China(Grant Nos.62201276,62350001,U22B2026,and 62471248)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300701)+1 种基金the Key R&D Program(Industry Foresight and Key Core Technologies)of Jiangsu Province(Grant No.BE2022071)Natural Science Research of Jiangsu Higher Education Institutions of China(Grant No.22KJB510007)。
文摘As the first stage of the quantum Internet,quantum key distribution(QKD)networks hold the promise of providing long-term security for diverse users.Most existing QKD networks have been constructed based on independent QKD protocols,and they commonly rely on the deployment of single-protocol trusted relay chains for long reach.Driven by the evolution of QKD protocols,large-scale QKD networking is expected to migrate from a single-protocol to a multi-protocol paradigm,during which some useful evolutionary elements for the later stages of the quantum Internet may be incorporated.In this work,we delve into a pivotal technique for large-scale QKD networking,namely,multi-protocol relay chaining.A multi-protocol relay chain is established by connecting a set of trusted/untrusted relays relying on multiple QKD protocols between a pair of QKD nodes.The structures of diverse multi-protocol relay chains are described,based on which the associated model is formulated and the policies are defined for the deployment of multi-protocol relay chains.Furthermore,we propose three multi-protocol relay chaining heuristics.Numerical simulations indicate that the designed heuristics can effectively reduce the number of trusted relays deployed and enhance the average security level versus the commonly used single-protocol trusted relay chaining methods on backbone network topologies.
基金Supported by the National Natural Science Foundation of China(No.61271238)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20123223110003)+1 种基金the University Natural Science Research Foundation of Jiangsu Province(No.11KJA510002)the Open Research Fund of National Laboratory of Solid State Microstructures(M25020,M25022)
文摘We propose a quantum multiple access communications scheme using Orbital Angular Momentum (OAM) sector states in the paper. In the scheme, each user has an individual modified Poincare Bloch sphere and encodes his information with his own corresponding sector OAM states. A prepared entangled photon pairs are separated at transmitter and receiver. At the transmitter, each user encodes his information with the sector OAM states on the photons and the superposition of the different sector OAM states is carried by the photons. Then the photons are transmitted through quantum noiseless channel to the receiver. At the receiver, each user could retrieve his information by coincidently measuring the transmitted photons with the receiver side photons which are modulated by a special prepared measurement basis. The theoretical analysis and the numerical simulations show that each user could get his information from the superposition state without error. It seems that this scheme provides a novel method for quantum multiple users communications.
基金supported by the Hunan Provincial Natural Science Foundation of China(Grant No.2019JJ50742)National Natural Science Foundation of China under Grant Nos.12174448 and 11604226Beijing Municipal Commission of Education under Grant No.CIT&TCD201904080。
文摘We present error-rejecting entanglement concentration protocols(ECPs)for partially entangled electron spins in quantum dots(QDs)with unknown and known parameters using quantum electrodynamics of QDs coupled with optical cavities,which can recover the partially entangled state to the maximally entangled state with unit fidelity even in the non-ideal experimental condition.The error-rejecting ECP for a partially entangled state utilizes parity check operations on electron spins within QDs.Furthermore,for a partially entangled state with known parameters,the ECP is devised through a parameter-splitting approach.The success probabilities of these two error-rejecting ECPs can be further improved by using the resource recycling method and iteration method.On account of their unit fidelity and considerable success probability,the error-rejecting ECPs have promising application value in improving the fidelity of quantum communication.
基金supported by the National Natural Science Foundation of China(Grant No.62001440).
文摘Quantum communication networks,such as quantum key distribution(QKD)networks,typically employ the measurement-resend mechanism between two users using quantum communication devices based on different quantum encoding types.To achieve direct communication between the devices with different quantum encoding types,in this paper,we propose encoding conversion schemes between the polarization bases(rectilinear,diagonal and circular bases)and the time-bin phase bases(two phase bases and time-bin basis)and design the quantum encoding converters.The theoretical analysis of the encoding conversion schemes is given in detail,and the basis correspondence of encoding conversion and the property of bit flip are revealed.The conversion relationship between polarization bases and time-bin phase bases can be easily selected by controlling a phase shifter.Since no optical switches are used in our scheme,the converter can be operated with high speed.The converters can also be modularized,which may be utilized to realize miniaturization in the future.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62071381 and 62301430)Shaanxi Fundamental Science Research Project for Mathematics and Physics (Grant No. 23JSY014)+1 种基金Scientific Research Plan Project of Shaanxi Education Department (Natural Science Special Project (Grant No. 23JK0680)Young Talent Fund of Xi’an Association for Science and Technology (Grant No. 959202313011)。
文摘Quantum secure direct communication(QSDC) is a communication method based on quantum mechanics and it is used to transmit secret messages. Unlike quantum key distribution, secret messages can be transmitted directly on a quantum channel with QSDC. Higher channel capacity and noise suppression capabilities are key to achieving longdistance quantum communication. Here, we report a continuous-variable QSDC scheme based on mask-coding and orbital angular momentum, in which the mask-coding is employed to protect the security of the transmitting messages and to suppress the influence of excess noise. The combination of orbital angular momentum and information block transmission effectively improves the secrecy capacity. In the 800 information blocks ×1310 bits length 10-km experiment, the results show a statistical average bit error rate of 0.38%, a system excess noise value of 0.0184 SNU, and a final secrecy capacity of 6.319×10~6 bps. Therefore, this scheme reduces error bits while increasing secrecy capacity, providing a solution for long-distance large-scale quantum communication, which is capable of transmitting text, images and other information of reasonable size.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62071381 and 62301430)Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.23JSY014)+1 种基金Scientific Research Plan Project of Shaanxi Education Department Natural Science Special Project(Grant No.23JK0680)Young Talent Fund of Xi’an Association for Science and Technology(Grant No.959202313011)。
文摘Continuous-variable quantum secure direct communication(CVQSDC)with Gaussian modulation(GM)demands a considerable quantity of random numbers during the preparation process and encodes them separately on the quadrature components of the quantum states.Hence,high-speed random number generators are required to satisfy this demand,which is difficult to implement in practical applications.CVQSDC with discrete modulation(DM),correspondingly,employs a finite number of quantum states to achieve encoding,which can circumvent the shortcomings of the GM scheme.Based on the advantages of DM,the issue of attaining the most optimal secrecy capacity and communication distance remains to be resolved.Here,we propose a CVQSDC protocol based on N-symbol amplitude phase shift keying(N-APSK),which exploits the Boltzmann-Maxwell distribution assisted probability shaping technique.In comparison with the uniform distribution,according to 32-APSK CVQSDC,the proposed scheme extends the communication distance by about 38%,while obtaining a higher secrecy capacity at the same communication distance.Furthermore,increasing the value of N will concurrently increase the quantity of rings in the constellation,thereby facilitating enhancements of communication distance.This work incorporates the modulation approaches prevalently employed in classical communication into the realm of quantum communication,attaining gratifying advancements in communication distance and secrecy capacity,and concurrently facilitating the integrated development of quantum communication and classical communication.
基金The National Natural Science Foundation of China(No.60873101)the Natural Science Foundation of Jiangsu Province(No.BK2008209)the Research Foundation of Nanjing University of Information Science and Technology(No.20080298)
文摘Based on mutual authentication and dense coding,a novel revised efficient quantum direct communication scheme is proposed.It is composed of two phases：the quantum state distribution process and the direct communication process.The purpose of the former is to authenticate Trent and users to each other,and let the two legitimate users（Alice and Bob）safely share the Bell states.While the latter aims to make direct communication to transmit a secret message between Alice and Bob.In order to prevent from Eve＇s eavesdropping as well as to authenticate each other simultaneously,a decoy photon checking technique is applied.Compared with other analogous protocols,the quantum state distribution process is more simple and feasible and the proposed scheme is more efficient;i.e.,the total efficiency is almost 100%.Security analysis shows that the proposed scheme is secure against the eavesdropping attacks,the impersonation attacks,and some special Trent＇s attacks,including the attacks by using different initial states.
文摘Trusted relays are the main state-of-the-art way to realize quantum key distribution networks.However,it is hard to require that all nodes in the network are fully trusted.In a multipath keytransmission mechanism,the nodes can be weakly trusted because the secret key can be split into many parts and each part is transmitted to the receiver through a different path.However,if the capacity of a node’s quantum key pool is poorly designed,an attacker,Eve may eavesdrop on the communicating parties’secret message by initiating a redirection attack.In this paper,we show that Eve can trigger a cascading collapse effect by collapsing one of the edges in the network and forcing the communication parties to transmit the message through the nodes controlled by Eve.The influence of the traffic transfer ratio and the control parameters of the edge load on the breakdown probability of the edge are analyzed using a simulation.In order to effectively defend against the cascading attack,it is important for the designer to handle the relationship between the traffic and the capacity of the quantum key pool of each node in the network.
基金Prospective Research Project on Future Networks of Jiangsu Province,China(No.BY2013095-1-18)
文摘With ensured network connectivity in quantum channels, the issue of distributing entangled particles in wireless quantum communication mesh networks can be equivalently regarded as a problem of quantum backbone nodes selection in order to save cost and reduce complexity. A minimum spanning tree（ MST）-based quantum distribution algorithm（ QDMST） is presented to construct the mesh backbone network. First, the articulation points are found,and for each connected block uncovered by the articulation points, the general centers are solved. Then, both articulation points and general centers are classified as backbone nodes and an M ST is formed. The quantum path between every two neighbor nodes on the MST is calculated. The nodes on these paths are also classified as backbone nodes. Simulation results validate the advantages of QDMST in the average backbone nodes number and average quantum channel distance compared to the existing random selection algorithm under multiple network scenarios.
基金Supported by National Natural Sciences Foundation of China under Grant No.60667001
文摘On basis of the nonlocality without entanglement proposed by Bennett,the properties of an orthogonal set of product states of two qutrits are revealed,i.e.,the transformation among different composite spaces can be realized by using three unitary operations,and the correlation between two composite spaces is found.These properties can be used to quantum communication and quantum cryptography.As examples,we propose a scheme of controlled quantum secure direct communication and one of quantum key distribution.It is shown that applying the product state of qutrit to quantum information processing not only is of the advantages of large capacity and high efficiency,but ensures the security.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10604008 and 10435020） and the Beijing Education Committee （Grant No XK100270454）.
文摘This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs （quantum key） shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.
基金Project supported by the National Natural Science Foundation of China （Grant No 10604008） and the Beijing Education Committee （Grant No XK100270454）.
文摘We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdropper, Eve, intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in the same state, and measures the returned photons with the measuring basis, with which Eve prepares the fake signal except for one photon. This attack increases neither the quantum channel losses nor the error rate in the sampling instances for eavesdropping check. It works for eavesdropping the secret message transmitted with the ping-pong protocol. Finally, we propose a way for improving the security of the ping-pong protocol.
基金Project supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China （Grant No. 60921063） and the National High Technology Research and Development Program of China （Grant No. 2013AA013601）.
文摘Wireless quantum communication networks transfer quantum state by teleportation. Existing research focuses on maximal entangled pairs. In this paper, we analyse the distributed wireless quantum communication networks with partially entangled pairs. A quantum routing scheme with multi-hop teleportation is proposed. With the proposed scheme, is not necessary for the quantum path to be consistent with the classical path. The quantum path and its associated classical path are established in a distributed way. Direct multi-hop teleportation is conducted on the selected path to transfer a quantum state from the source to the destination. Based on the feature of multi-hop teleportation using partially entangled pairs, if the node number of the quantum path is even, the destination node will add another teleportation at itself. We simulated the performance of distributed wireless quantum communication networks with a partially entangled state. The probability of transferring the quantum state successfully is statistically analyzed. Our work shows that multi-hop teleportation on distributed wireless quantum networks with partially entangled pairs is feasible.
基金supported by the Natural Science Foundation of Jiangsu Provincial Universities, China (Grant No. 10KJB180004)
文摘We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60572071 and 60873101)Natural Science Foundation of Jiangsu Province (Grant Nos BM2006504, BK2007104 and BK2008209)College Natural Science Foundation of Jiangsu Province (Grant No 06KJB520137)
文摘A novel efficient deterministic secure quantum communication scheme based on four-qubit cluster states and single-photon identity authentication is proposed. In this scheme, the two authenticated users can transmit two bits of classical information per cluster state, and its efficiency of the quantum communication is 1/3, which is approximately 1.67 times that of the previous protocol presented by Wang et al [Chin. Phys. Lett. 23 （2006） 2658]. Security analysis shows the present scheme is secure against intercept-resend attack and the impersonator＇s attack. Furthermore, it is more economic with present-day techniques and easily processed by a one-way quantum computer.
