Continuous Variable Quantum Network Dialogue Protocols Based On Single-mode Squeezed States And GHZ States

The rapid development of information technology has accelerated the exchange and transmission of information.In classical information security theory,it is difficult for a confidential classical channel to detect eavesdroppers' attacks on transmission information in time.Quantum private communication with higher security has attracted more and more attention from academia,finance and military fields.Communication protocols designed by taking advantage of quantum states characteristics possess high transmission efficiency and their unconditional security are usually guaranteed by non-cloning theorem and uncertainty principle.Quantum dialogue is a two-way quantum secure direct communication.Both parties of communication are sender of information and receiver of information.Quantum dialogue directly employs quantum states as the transmission information carrier.Without sharing quantum key before communication,the efficiency of protocol has been improved.Compared with discrete-variable quantum communication,the continuous-variable quantum communication has higher transmission efficiency and lower channel loss,and it can be realized by optical devices easily.Therefore,more and more researches focus on continuous variable quantum dialogue protocol at present.In this dissertation,two quantum network dialogue protocols are designed based on continuous variable single-mode squeezed states and continuous variable GHZ entangled states,and the security of the two protocols are analyzed.The main tasks are as follows:A new quantum network dialogue protocol is designed by using quantum properties of continuous variable single-mode squeezed states.Alice prepares a number of single-mode squeezed states and sends them to Bob,Charlie and other communication parties,respectively.After confirming the security of transmission channel,Bob,Charlie and other communication parties encode the secret information into single-mode squeezed states and insert random variable obeying Gaussian distribution.Then,they sent optical modes to Alice.Alice,Bob,Charlie and other communication parties can infer other party's secret information with the help of measurement results.In addition,each communication party could choose another communication party for quantum dialogue.Compared with dialogue protocols based on discrete variable quantum states,the new quantum dialogue protocol is easier to implement.A quantum network dialogue protocol based on continuous variable GHZ entangled states is proposed.Quantum dialogue can be conducted simultaneously among multiple legitimate communication parties.The security of the proposed quantum dialogue protocol is ensured by entanglement properties of GHZ states.Security analysis shows that the quantum network dialogue protocol can resist spectroscope attack.