Quantum Key Distribution With Identity Verification Of Quadripartite Entangled States

Quantum key distribution (QKD) is based on the foundmental of Quantum Mechanics theory. The security of QKD is guaranteed by the characters of Quantum Mechanics and it utilize the quantum effect of micro-particle to make security. The quantum communication is extensivly applied to study at home and abroad after Stephen Weisner who first proposed'quantum monetary'in 1970's. And also the success of QKD experiments is reported instantly. The advantages of QKD is beyond classical cryptography communication, more and more country, military mechanisms, financial institutions is concern on the subject. In the field of quantum communication multiple quantum entangled states have more excellent properties, so it have prodigious research value.First of all we overview the latest achievements of QKD after that I emphatically studied quadric-quantum entangled states. Second I orthogonal transformed a certain kind of quadric-quantum entangled states and gained a group complete orthogonal basis functions, and then do packet processing to them, after that I designed a particular encoding rule which utilized a certain function to mixed the information of secret key and the authentication of Alice, then Alice transmitted all these presulfided entangled quantum state to Alice by communication channel of optical fiber or free space. Bob could extract these information such as the key and authentication.The former QKD protocol couldn't resistance intermediary attacks------intruder role impersonate. This paper using quadric-quantum entangled states as carrier to send the information which is contain the information of secret key and the authentication of Alice that is prepared already. This method could not only improve the confidentiality but also effectively prevent intruder role impersonate. Besides this, by means of appropriate adjustment the protocol could adapt to different communication channel situation, while the safety and effectiveness isn't affected.We discussed the security of QKD quadripartite entangled states. First I calculated the quantum entropy then studied the security when QKD and identity authenticate contemporarily. It is proved that the protocol could not only counteract the mid-attack but also could improve it's safety.At last I complete a series of computer simulation of quadric-quantum entangled states key distribution which is based on the theory of quantum information theory. The result of quantum entropy and fidelity is compared with BB84, B92, EPR protocol quantificational. We find that the fidelity performance is reduced while Von Neumann entropy and the utilization rate of qubit for QKD is beyond the other protocol.