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
Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast p...Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast protocol can not deal with them fully. Gossip-based group key distribution idea for wide-area dissemination was provided. It is based on an gossip-based loss recovery control mechanism. It can provide a probabilistic reliable guarantee for a information dissemination to reach every group member, which can achieve scalability and reliability. To achieve full reliability, three layers protocol model in group key distribution was provided. One is best effect layer, which provides unreliable dissemination. Other is gossip-based loss recovery layer, which provides probabilistic reliable guarantee. Last is vsync-based layer, which provide deterministic loss recovery. We integrate probabilistic loss recovery method with deterministic one. The model possess scalability that probabilistic method has and full reliability prosthesis by vsync-based. To evaluate the effectiveness of gossip technique in scalable and reliable multicast protocols. We have compared gossip protocol with other reliable multicast protocols. Experimental result shows that gossip protocol has better scalability than other.展开更多
Quantum key distribution （QKD） is used in quantum cryptographic systems to exchange secret key between parties who need to communicate secretly. According to the structure of European Secoqc QKD network, a QKD proto...Quantum key distribution （QKD） is used in quantum cryptographic systems to exchange secret key between parties who need to communicate secretly. According to the structure of European Secoqc QKD network, a QKD protocol is proposed. Entanglement swapping between Einstein-Podolsky-Rosen （EPR） pairs can be used to exchange message bits in two remote places. Based on this idea, n ＋ 1 EPR pairs are used as logical quan- tum channel （for n nodes per routing）, while measurements of Bell operator are transmitted by classical channel. Random space quantum channel selection is exploited in our protocol to improve the probability of revealing Eve. Compared with traditional EPR protocol, the proposed protocol exhibits many features, which are minutely described.展开更多
The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-ba...The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.展开更多
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.
文摘Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast protocol can not deal with them fully. Gossip-based group key distribution idea for wide-area dissemination was provided. It is based on an gossip-based loss recovery control mechanism. It can provide a probabilistic reliable guarantee for a information dissemination to reach every group member, which can achieve scalability and reliability. To achieve full reliability, three layers protocol model in group key distribution was provided. One is best effect layer, which provides unreliable dissemination. Other is gossip-based loss recovery layer, which provides probabilistic reliable guarantee. Last is vsync-based layer, which provide deterministic loss recovery. We integrate probabilistic loss recovery method with deterministic one. The model possess scalability that probabilistic method has and full reliability prosthesis by vsync-based. To evaluate the effectiveness of gossip technique in scalable and reliable multicast protocols. We have compared gossip protocol with other reliable multicast protocols. Experimental result shows that gossip protocol has better scalability than other.
文摘Quantum key distribution （QKD） is used in quantum cryptographic systems to exchange secret key between parties who need to communicate secretly. According to the structure of European Secoqc QKD network, a QKD protocol is proposed. Entanglement swapping between Einstein-Podolsky-Rosen （EPR） pairs can be used to exchange message bits in two remote places. Based on this idea, n ＋ 1 EPR pairs are used as logical quan- tum channel （for n nodes per routing）, while measurements of Bell operator are transmitted by classical channel. Random space quantum channel selection is exploited in our protocol to improve the probability of revealing Eve. Compared with traditional EPR protocol, the proposed protocol exhibits many features, which are minutely described.
文摘The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.
