This paper points out that, due to a flaw in the sender＇s encoding, the receiver in Gao et al.＇s controlled quantum secret direct communication （CQSDC） protocol [Chin. Phys. 14 （2005）, No. 5, p. 893] can reveal ...This paper points out that, due to a flaw in the sender＇s encoding, the receiver in Gao et al.＇s controlled quantum secret direct communication （CQSDC） protocol [Chin. Phys. 14 （2005）, No. 5, p. 893] can reveal the whole secret message without permission from the controller. An improvement is proposed to avoid this flaw.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, r...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 effciency twice that of the other corresponding fault tolerant QSDC protocols. Furthermore, the proposed protocols are free from Trojan horse attacks.展开更多
This study proposes a new coding function for the symmetric W state.Based on the new coding function,a theoretical protocol of deterministic quantum communication(DQC) is proposed.The sender can use the proposed codin...This study proposes a new coding function for the symmetric W state.Based on the new coding function,a theoretical protocol of deterministic quantum communication(DQC) is proposed.The sender can use the proposed coding function to encode his/her message,and the receiver can perform the imperfect Bell measurement to obtain the sender's message.In comparison to the existing DQC protocols that also use the W class state,the proposed protocol is more efcient and also more practical within today's technology.Moreover,the security of this protocol is analyzed to show that any eavesdropper will be detected with a very high probability under both the ideal and the noisy quantum channel.展开更多
A multi-party quantum secret sharing protocol using two entangled states,is proposed and analyzed.In this protocol,without requiring to generate any photon or do any local unitary operation,an agent can obtain a shado...A multi-party quantum secret sharing protocol using two entangled states,is proposed and analyzed.In this protocol,without requiring to generate any photon or do any local unitary operation,an agent can obtain a shadow of the secret key by simply performing a measurement of single photon.Furthermore,the security of the protocol is analyzed.It shows that no agent can obtain the manager's secret without the help of the other agents,and any eavesdropper will be detected if he/she tries to steal the manager's secret under ideal or noisy quantum channels.展开更多
This paper is based on previous quantum encryption proposed by researchers developing a scheme for cryptography using symmetric keys.This study has pointed out that the scheme consists of a pitfall that could lead to ...This paper is based on previous quantum encryption proposed by researchers developing a scheme for cryptography using symmetric keys.This study has pointed out that the scheme consists of a pitfall that could lead to a controlled-NOT(CNOT)extraction attack.A malicious user can obtain the secret message of a sender without being detected by using a sequence of single photons and a controlled-NOT gate.展开更多
基金supported by the National Science Council,Taiwan,(Grant No. NSC 100-2221-E-006-152-MY3)
文摘This paper points out that, due to a flaw in the sender＇s encoding, the receiver in Gao et al.＇s controlled quantum secret direct communication （CQSDC） protocol [Chin. Phys. 14 （2005）, No. 5, p. 893] can reveal the whole secret message without permission from the controller. An improvement is proposed to avoid this flaw.
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 effciency 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 National Science Council of the Republic of China(Grant No.NSC 98-2221-E-006-097-MY3)
文摘This study proposes a new coding function for the symmetric W state.Based on the new coding function,a theoretical protocol of deterministic quantum communication(DQC) is proposed.The sender can use the proposed coding function to encode his/her message,and the receiver can perform the imperfect Bell measurement to obtain the sender's message.In comparison to the existing DQC protocols that also use the W class state,the proposed protocol is more efcient and also more practical within today's technology.Moreover,the security of this protocol is analyzed to show that any eavesdropper will be detected with a very high probability under both the ideal and the noisy quantum channel.
基金supported by the National Science Council of the Republic of China,Taiwan,China (Grant No. NSC 98-2221-E-006-097-MY3)
文摘A multi-party quantum secret sharing protocol using two entangled states,is proposed and analyzed.In this protocol,without requiring to generate any photon or do any local unitary operation,an agent can obtain a shadow of the secret key by simply performing a measurement of single photon.Furthermore,the security of the protocol is analyzed.It shows that no agent can obtain the manager's secret without the help of the other agents,and any eavesdropper will be detected if he/she tries to steal the manager's secret under ideal or noisy quantum channels.
基金supported by the Research Center of Quantum Communication and Security,National Cheng Kung University,Taiwan,China (Grant No. D100-36002)
文摘This paper is based on previous quantum encryption proposed by researchers developing a scheme for cryptography using symmetric keys.This study has pointed out that the scheme consists of a pitfall that could lead to a controlled-NOT(CNOT)extraction attack.A malicious user can obtain the secret message of a sender without being detected by using a sequence of single photons and a controlled-NOT gate.
