Research On Third-party Continuous Variable Quantum Key Agreement Protocol

Quantum key distribution and quantum key negotiation are two very important branches in the field of quantum cryptography.Unlike the one-way transmission of quantum key distribution,in the quantum key agreement protocol,the key is determined by all participants and jointly,All participants contribute the same to the key.These characteristics make quantum key negotiation have higher security and fairness.Since 2004,Zhou Nanrun proposed the first two-party quantum key agreement protocol,and more and more QKA protocols have been proposed and extended from both parties to multiple parties.However,most of the researches on QKA are based on discrete variable quantum states,and the QKA protocol based on discrete variables has the following disadvantages:(1)The ideal single photon source and single photon detector are difficult to implement,are affected by the detector noise,and have dark counts However,there is still a lack of efficient single-photon detectors.(2)Single-photon transmission in a channel is susceptible to environmental noise and easily absorbed,resulting in limited transmission efficiency and transmission distance.Compared with discrete variables,continuous variable protocols have the advantages of multi-photon beam characteristics,strong immunity to noise,availability of detector noise,high number of key bits carried by the carrier,and strong compatibility with existing optical fiber communication systems.This paper focuses on the hot topic of continuous variable quantum key negotiation.With the help of continuous variable quantum states such as continuous variable GHZ state,continuous variable two-mode squeezed state,and coherent state,three quantum key agreement protocols based on continuous variable quantum state are designed.The correctness analysis and security analysis of the proposed protocol are carried out.The specific research contents are as follows:(1)Using a continuous variable GHZ state,a multi-party quantum key agreement protocol based on a third party is proposed.The third party prepares the continuous variable GHZ state and sends the output modules to the participants.Participants encode their keys in quantum states through translation operations until they receive a quantum states that encodes all participants' key information.And participants can calculate a common key.Security analysis shows that the proposed QKA protocol can not only resist the attacks of participants,but also resist collusion attacks and beam splitter attacks.(2)In order to solve the hacker attack caused by the detector,a coherentstate-based measurement device-independent quantum key agreement protocol is proposed.First,a two-party quantum key agreement protocol is proposed,and then it is extended to multiple parties.According to the security of the PM scheme is equivalent to the corresponding EB scheme.In order to facilitate the security analysis,we also describe the corresponding EB scheme,and then analyze the security of the protocol.The analysis shows that the protocol can resist common attacks.(3)Based on the continuous variable dual-mode compression state,a continuous variable multi-party QKA protocol controlled by a third party is proposed.A third party prepares a continuous variable two-mode squeezed state and sends an output mode to one of the participants.Participants encode their own keys sequentially in a linear manner,then a third party performs an entanglement detection,finally announces the decoy state,and participates in the combination to remove the deceive state and calculate a common key.Security analysis shows that the proposed QKA protocol can resist man-in-the-middle attacks and collusion attacks.