A novel scheme of controlled secure quantum dialogue by using Brown states was proposed in this paper.It this scheme,Alice,Bob and Charlie shared a five-particle Brown states.Alice made unitary operations on two particles of the Brown states to realize encoding her secret calssical message.Similarly,Bob performed corresponding unitary transformations to another two particles to encode the information that he wanted to send to Alice.Later,Charlie made Brown base states joint measurement on the Brown final state and announced the measured results.Alice and Bob deduced the opposite party′s information according to Charlie′s announced measurement results and her(his)unitary operation when encoding.They completed quantum dialogue successfully.Then the scheme′s security was discussed and a conclusion was drawn.Compared with the previous quantum dialogues,the secure quantum dialogue scheme adds the controlled party,ensures the communication security,and increases the particles number involving in the communication process and the coding efficiency.
A novel scheme of controlled secure quantum dialogue by using Brown states was proposed in this paper.It this scheme,Alice,Bob and Charlie shared a five-particle Brown states.Alice made unitary operations on two particles of the Brown states to realize encoding her secret calssical message.Similarly,Bob performed corresponding unitary transformations to another two particles to encode the information that he wanted to send to Alice.Later,Charlie made Brown base states joint measurement on the Brown final state and announced the measured results.Alice and Bob deduced the opposite party′s information according to Charlie′s announced measurement results and her(his)unitary operation when encoding.They completed quantum dialogue successfully.Then the scheme′s security was discussed and a conclusion was drawn.Compared with the previous quantum dialogues,the secure quantum dialogue scheme adds the controlled party,ensures the communication security,and increases the particles number involving in the communication process and the coding efficiency.
In this paper, a controlled quantum dialogue (CQD) protocol based on Brown states is proposed. In the beginning, the controller Cindy creates a five-qubit Brown state as the channel and distributes it to the other two communication participants, Alice and Bob. Then, Alice and Bob can encode the secret key by performing unitary operation onto the entangled particles that Cindy sends to them. Finally, the messages can be exchanged by entanglement swapping and the results of Bell state measurement. The security analysis shows that our protocol cannot only solves the problem of information leakage, but also can effectively prevent a variety of well-known attacks. Under the control of Cindy, there are two possible decoding methods for participants to obtain each other's information, improving communication security. In addition, this protocol does not involve complex quantum operations and demonstrates a good physical operational feasibility.
Abstract A controlled semi-quantum dialogue protocol is proposed that uses semi-quantum cryptography and the concept of ‘control’. In this scheme, the supervisor Charlie prepares a large number of entangled photon pairs and separates them into an S A for verification and an S B for encoding. The quantum-capable party Alice and the classical communication party Bob proceed to encode on the S B sequence only after confirming the security of the channel. Finally, Alice performs measurements and announces the results to finalise the communication. This protocol ensures that secret information is exchanged between Alice and Bob only with Charlie’s permission, while Charlie has no access to the communicators’ secret information during the whole process. In terms of security, the protocol contains two strict security checks and accounts for noise, making it robust against both internal and external attacks, which greatly improves the security and reliability of the protocol. Finally, the efficiency analysis demonstrates that the protocol outperforms other existing protocols in terms of efficiency and its actual efficiency can approach the theoretical limit through optimization.
A scheme of quantum dialogue was proposed based on four-particle omega state.First,Bob,a communication party,prepared a four-particle omega state,encoded classical secret information by performing an approprite unitary transformation on two particles of the omega state and sent them to Alice.Then,Alice also performed an approprite unitary transformation on the two particles to encode secret information and sent back to Bob.Finally,Bob made joint measurement to final omega state,and announced the results.Alice and Bob,two parties of communication,could decode classical information the opposite one transfers,according to the announced measurement results and itself unitary operator,making the bidirectional communication come true.The result shows that the communication scheme only transfers two particles and makes unitary operations twice,and two communication parties get the opposite four-bit classcical information.It realizes both two-way communication of classical information with quantum channel and dense encoding to improve the communication capacity.The Eve′s intercept-resend attack can be found in time by inserting decoy photons in the system to raise the security of communication system.
In this paper, a controlled quantum dialogue (CQD) scheme based on different unspecific two-particle entangled state is proposed, in which legitimate users can exchange their secret messages according to unitary operations they chose and measurement results published by Charlie, realizing transmitting unspecific secrets by using unspecific entangled state. We insert decoy particles twice and get rid of useless secret messages carried by F particles to ensure security of the whole communication system, realizing the three-times channel detection. Compared to previous CQD protocols, the proposed scheme is proved to stand attack from third-party controller, and it is very secure.
A novel controlled quantum secure direct communication scheme by using five-particle cluster states is proposed.In this scheme,the quantum channel between the sender Alice,the controller Charlie and the receiver Bob consists of an ordered sequence of five-particle cluster states which are prepared by Alice.After determine the security of quantum channel,Alice prepares the encoded Bell-state sequences,and Alice and Bob perform Bell-state measurements on the particles at hand,respectively,and then Charlie may make a single-particle measurement.Then Alice and Charlie tell their result to Bob,Bob can get the secret information through the analysis of their results.In our scheme,the information-carrying particles do not need to be transmitted over the public channel.Moreover,we analyze the security of the controlled quantum secure direct communication protocol,and demonstrate that our scheme is determinate and secure.In the future,our scheme might be realizable based on present experimental technology.
In a sense,quantum teleportation by which information could only be transferred in one-way is not a perfect mode of communication.Thus,a scheme of two-way quantum communication controlled by a third party is proposed.Firstly,both sides of communication need accomplish information encoding through some unitary transformations.Then they should perform Bell-state measurements(BSMs) to their own qubits respectively,and announce the measured results.With the permission of the controller,two sides of communication could realize the quantum dialogue without divulging information to controller.Because of the join of a third party,safety of quantum dialogue is greatly enhanced,which makes this scheme better.According to the realization of secure two-way quantum communication,the scheme may be a good reference in practical application of quantum secure dialogue and quantum private communication.