Quantum Secure Direct Communication Based On Grover Algorithm

In information age,communication security is an indispensable internal demand.As a new form to realize secure communication,the unconditional security of quantum secure direct communication has been proved theoretically.It does not need to generate shared keys for encrypting information in advance,but directly transmits the confidential information in the quantum channel.Therefore,it has attracted considerable attention of the researchers.Grover algorithm is a research hotspot in quantum algorithm,which has the advantage of significant acceleration.Now,there are a few studies combining Grover algorithm and quantum secure direct communication,and the security is poor under man-in-the-middle attack.This paper focuses on quantum secure direct communication based on Grover algorithm,which can remedy the defects existed in presented protocols.In addition,to facilitate the realizability of quantum secure direct communication with the limited quantum resources in the real world,a multi-party semi-quantum secure direct communication protocol is also studied in this paper.With careful research,some innovative progress has been made,as follows:(1)Two quantum secure direct communication protocols based on four-particle cluster states and Grover algorithm are designed.Both protocols employ four-particle cluster states with entanglement persistency as quantum resources and two operators in two-qubit Grover algorithm to encode and decode information.Compared with the existing CQSDC based on Grover algorithm and conventional CQSDC based on six-qubits entangled states,these two protocols outperform the existing protocols in resisting man-in-the-middle attack,a dishonest receiver and modification attack,and they obtain high quantum communication efficiency.(2)A controlled quantum secure direct communication based on Grover algorithm and authentication is designed.Under the supervision of the controller Charlie,the sender Alice can securely send the information to the receiver Bob.A unique property of two-qubit Grover algorithm is used to encode and decode information.The security of the designed protocol can be effectively guaranteed with the security detection particles,associated with secret identity sequences.In comparison with the existing QSDC and CQSDC protocols based on Grover algorithm,the qubit efficiency of the proposed protocol is not only equal to the optimal efficiency,but also can effectively resist man-in-the-middle attack.Furthermore,the proposed protocol can be implemented easier with the current technology with product states of single particle as the information carrier.(3)A three-party semi-quantum secure direct communication(SQSDC)protocol with GHZ entangled states is presented,which includes three communication parties:quantum Charlie,classical Alice and classical Bob.In this protocol,two classical parties are allowed to send secret information to the quantum party simultaneously.The proposed SQSDC can be converted into a three-party semi-quantum dialogue protocol with adding some encoding operations in quantum party.Based on the characteristics of GHZ states,two protocols can be generalized into communication schemes involving more than three parties.In addition,a multi-party semi-quantum secure direct communication protocol is proposed by introducing quantum error correction coding strategy,which can resist noise in the devices to some extent.The security of four proposed protocols is analyzed under common attack strategies,such as intercept-resend attack and entanglement measurement attack,etc.Compared with the existing SQSDC protocols,the proposed three-party SQSDC protocol obtians higher qubit efficiency.The efficiency of three-party semi-quantum dialogue protocol is slightly lower than the optimal quantum efficiency in the current semi-quantum dialogue protocols,but the protocol can prevent Alice and Bob from cheating Charlie together.(4)Regarding the security problem of personal information leakage,the applications of the designed protocols in personal information management are discussed,and take the membership system of an entity chain store as an example to elaborate it in detail.