Deterministic Secure Quantum Communication Achieved By Using Quantum Swapping

The main goals of direct communication are to fred out(1) how two authorized parties, who share no secret information initially,can transmit secret messages deterministically;and(2) how two authorized parties can detect whether the eavesdropper has been monitored or not,and may ensure that the secret data has not been compromised in transit.It is impossible to solve these problems by using classical information technology.However,by considering the characteristic features of qubit,these difficulties can be overcome.Quantum secure direct communication(QSDC) turns into a new quantum communication protocol in which the secret message is deterministically transmitted between the two authorized parties,without first establishing a key encrypt.This dissertation consists of four chapters.In the first three chapters,we introduced quantum information,some foundations of quantum informatics and some quantum communication protocols.In chapter 4,two new deterministic secure quantum communication protocols are proposed.In two new deterministic secure quantum communication protocols,no particle is transported between two authorized parties,and two authorized parties(Alice and Bob) initially share no EPR pairs directly,but they can finally share a secret certain sequence of bits for a character code.These protocols can be implemented in practice,especially for the customer-bank-customer.