Design And Analysis Of Multi-party Quantum Key Agreement Protocols Based On Several Types Of Quantum States

Quantum cryptography is based on quantum mechanics and classical cryptography,using the quantum properties of micro particles to protect information,which is a new development direction of cryptography.Being a a research direction of quantum cryptography protocol,quantum key agreement requires that the shared key cannot be determined by any party,it is a protocol that communication parties establish the shared key fairly according to their private key information.Quantum state is the core resource of quantum information technology,which is divided into non entangled state and entangled state.Quantum key agreement is a protocol in which two or more parties can establish a shared key based on their own secret key,and the shared key cannot be determined by any party.It is an important branch of the quantum cryptography protocol.Quantum state is the core resource of quantum information technology and is divided into non-entangled states and entangled states.Based on the non entangled state,entangled state and entangled state combined with non entangled state,three key agreement protocols are proposed respectively in this dissertation:1.Using locally indistinguishable orthogonal direct product states as quantum resources,a new multi-party quantum key agreement protocol is designed based on non-entangled states.Participants choose to perform x operation or Z operation according to their own key,and send the quantum state after operation to other participants,forming a tree-like quantum structure.Because different particles belonging to the same orthogonal direct product state are transmitted separately,the participants cannot know the state of other particles,so the information can be guaranteed not to leak and the security of the protocol can be guaranteed to the greatest extent2.Based on the four-particle entangled state,an efficient multi-party quantum key agreement protocol is designed.Participants decide whether to perform x operation on quantum state according to their own key.Due to the characteristics of cluster state,participants can get shared key through state measurement.The protocol adopts the methods of delay measurement and decoy particles to ensure the security of the protocol,and adopts the two-way rotation and block transmission to realize the efficient information transmission.3.Combining entangled state with non entangled state,a practical multi-party quantum key agreement protocol is designed.The protocol selects the simplest single particle and Bell state as the quantum resource,and divides the participants into two groups first,exchanges the key within the group,and then rotates them separately,ensuring that everyone can participate in the generation of the decision key fairly,and no one can decide the key independently.Compared with other multi-party quantum key agreement protocols,the efficiency of the protocol has been significantly improved.At the same time,because the existing technology can prepare single particle and Bell state,our protocol has strong practicability.