A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as ...A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as the subnet gateway, a two-user subnet and a single-fiber access link, which is realized by the Faraday-Michelson interferometer set-ups. The techniques of the quantum router, optical switch and trusted relay are assembled here to guarantee the feasibility and expandability of the quantum cryptography network. Five nodes of the network are located in the government departments and the secure keys generated by the quantum key distribution network are utilized to encrypt the instant video, sound, text messages and confidential files transmitting between these bureaus. The whole implementation including the hierarchical quantum cryptographic communication network links and the corresponding application software shows a big step toward the practical user-oriented network with a high security level.展开更多
From the perspective of information theory and cryptography,the security of two quantum dialogue protocols and a bidirectional quantum secure direct communi-cation(QSDC) protocol was analyzed,and it was pointed out th...From the perspective of information theory and cryptography,the security of two quantum dialogue protocols and a bidirectional quantum secure direct communi-cation(QSDC) protocol was analyzed,and it was pointed out that the transmitted information would be partly leaked out in them.That is,any eavesdropper can elicit some information about the secrets from the public annunciations of the legal us-ers.This phenomenon should have been strictly forbidden in a quantum secure communication.In fact,this problem exists in quite a few recent proposals and,therefore,it deserves more research attention in the following related study.展开更多
Security in communication is vital in modern life. At present, security is realized by an encryption process in cryptography. It is unbelievable if a secure communication is achievable without encryption. In quantum c...Security in communication is vital in modern life. At present, security is realized by an encryption process in cryptography. It is unbelievable if a secure communication is achievable without encryption. In quantum cryptography, there is a unique form of quantum communication, quantum secure direct communication, where secret information is transmitted directly over a quantum channel. Quantum secure direct communication is drastically distinct from our conventional concept of secure communication, because it does not require key distribution, key storage and ciphertext transmission, and eliminates the encryption procedure completely. Hence it avoids in principle all the security loopholes associated with key and ciphertext in traditional secure communications. For practical implementation, defects always exist in real devices and it may downgrade the security. Among the various device imperfections, those with the measurement devices are the most prominent and serious ones. Here we report a measurementdevice-independent quantum secure direct communication protocol using Einstein-Podolsky-Rosen pairs. This protocol eradicates the security vulnerabilities associated with the measurement device,and greatly enhances the practical security of quantum secure direct communication. In addition to the security advantage, this protocol has an extended communication distance, and a high communication capacity.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
A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being dete...A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being detected. A quantum secret-sharing protocol is presents here, which mends the security loophole of the original secret-sharing protocol, and doubles the information capacity.展开更多
This work proposes two fault tolerant quantum secure direct communication （QSDC） protocols which are robust against two kinds of collective noises： the collective-dephasing noises and the collective-rotation noises...This work proposes two fault tolerant quantum secure direct communication （QSDC） protocols which are robust against two kinds of collective noises： the collective-dephasing noises and the collective-rotation noises, respectively. The two QSDC protocols are constructed from four-qubit DF states which consist of two logical qubits. The receiver simply performs two Bell state measurements （rather than four-qubit joint measurements） to obtain the secret message. The protocols have qubit efficiency twice that of the other corresponding fault tolerant QSDC protocols. Furthermore, the proposed protocols are free from Trojan horse attacks.展开更多
We present a quantum secret sharing scheme between multiparty (m members in Group 1) and multiparty (n members in Group 2), and analyze its security. This scheme takes EPR pairs in Bell states as quantum resources. In...We present a quantum secret sharing scheme between multiparty (m members in Group 1) and multiparty (n members in Group 2), and analyze its security. This scheme takes EPR pairs in Bell states as quantum resources. In order to obtain the shared key, all members only need to perform Bell measurements, rather than perform any local unitary operation. The total efficiency in this scheme approaches 100% as the classical information exchanged is not necessary except for the eavesdropping checks.展开更多
基金Supported by the Wuhu Government and China Telecommunications Corporation, Wuhu Branch, and National Basic Research Program of China (Grant No. 2006CB921900)National Natural Science Foundation of China (Grant Nos. 60537020, 60621064)Innovation Funds of Chinese Academy of Sciences
文摘A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as the subnet gateway, a two-user subnet and a single-fiber access link, which is realized by the Faraday-Michelson interferometer set-ups. The techniques of the quantum router, optical switch and trusted relay are assembled here to guarantee the feasibility and expandability of the quantum cryptography network. Five nodes of the network are located in the government departments and the secure keys generated by the quantum key distribution network are utilized to encrypt the instant video, sound, text messages and confidential files transmitting between these bureaus. The whole implementation including the hierarchical quantum cryptographic communication network links and the corresponding application software shows a big step toward the practical user-oriented network with a high security level.
基金the National High Technology Research and Development Program of China(Grant No.2006AA01Z419)the National Natural Science Foundation of China(Grant Nos.90604023 and 60373059)+3 种基金the National Research Foundation for the Doctoral Program of Higher Edu- cation of China(Grant No.20040013007)the National Laboratory for Modern Communications Science Foundation of China(Grant No.9140C1101010601)the Natural Science Foundation of Beijing(Grant No.4072020)the ISN Open Foundation
文摘From the perspective of information theory and cryptography,the security of two quantum dialogue protocols and a bidirectional quantum secure direct communi-cation(QSDC) protocol was analyzed,and it was pointed out that the transmitted information would be partly leaked out in them.That is,any eavesdropper can elicit some information about the secrets from the public annunciations of the legal us-ers.This phenomenon should have been strictly forbidden in a quantum secure communication.In fact,this problem exists in quite a few recent proposals and,therefore,it deserves more research attention in the following related study.
基金supported by the National Basic Research Program of China(2017YFA0303700 and 2015CB921001)the National Natural Science Foundation of China(61726801,11474168 and 11474181)the Beijing Advanced Innovation Center for Future Chip(ICFC)
文摘Security in communication is vital in modern life. At present, security is realized by an encryption process in cryptography. It is unbelievable if a secure communication is achievable without encryption. In quantum cryptography, there is a unique form of quantum communication, quantum secure direct communication, where secret information is transmitted directly over a quantum channel. Quantum secure direct communication is drastically distinct from our conventional concept of secure communication, because it does not require key distribution, key storage and ciphertext transmission, and eliminates the encryption procedure completely. Hence it avoids in principle all the security loopholes associated with key and ciphertext in traditional secure communications. For practical implementation, defects always exist in real devices and it may downgrade the security. Among the various device imperfections, those with the measurement devices are the most prominent and serious ones. Here we report a measurementdevice-independent quantum secure direct communication protocol using Einstein-Podolsky-Rosen pairs. This protocol eradicates the security vulnerabilities associated with the measurement device,and greatly enhances the practical security of quantum secure direct communication. In addition to the security advantage, this protocol has an extended communication distance, and a high communication capacity.
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 (GrantNos. 10775076 and 60635040)the National Basic Research Program of China (Grant No. 2006CB921106)the SRFPD Program of Education Ministry of China
文摘A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being detected. A quantum secret-sharing protocol is presents here, which mends the security loophole of the original secret-sharing protocol, and doubles the information capacity.
基金supported by the National Science Council, Taiwan, China (Grant No. NSC98-2221-E-006-097-MY3)
文摘This work proposes two fault tolerant quantum secure direct communication （QSDC） protocols which are robust against two kinds of collective noises： the collective-dephasing noises and the collective-rotation noises, respectively. The two QSDC protocols are constructed from four-qubit DF states which consist of two logical qubits. The receiver simply performs two Bell state measurements （rather than four-qubit joint measurements） to obtain the secret message. The protocols have qubit efficiency twice that of the other corresponding fault tolerant QSDC protocols. Furthermore, the proposed protocols are free from Trojan horse attacks.
基金supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No. 90818005)the National Natural Science Foundation of China (Grant Nos. 60903217, 60773032and 60773114)the Ph.D. Program Foundation of Ministry of Education of China (Grant No. 20060358014)
文摘We present a quantum secret sharing scheme between multiparty (m members in Group 1) and multiparty (n members in Group 2), and analyze its security. This scheme takes EPR pairs in Bell states as quantum resources. In order to obtain the shared key, all members only need to perform Bell measurements, rather than perform any local unitary operation. The total efficiency in this scheme approaches 100% as the classical information exchanged is not necessary except for the eavesdropping checks.
