Design And Analysis Of Quantum Key Agreement Protocol

Quantum cryptography is a new cryptosystem which combines the classical cryptography theory with the basic principles of quantum mechanics.Its security is determined by the basic characteristics and principles of quantum mechanics and has nothing to do with the computational ability of attackers.Therefore,it has a good ability to resist the attacks of quantum computation,which has attracted extensive attention in cryptography field.Quantum key agreement,which can resist internal attacks and several common external attacks and can satisfy fairness,is a key agreement based on quantum cryptosystem,and has been becoming one of the hot topics in the field of quantum cryptography.By analyzing the existing quantum key agreement protocols,based on ideal environment and collective noise environment,this dissertation proposes the following three quantum key agreement protocols:1.By utilizing the characteristics of the W-state,a three-party and a multi-party quantum key agreement protocols are firstly proposed.The protocols adopt the methods of delay measurement and decoy photons to ensure the fairness and security.The efficiency of the protocols are improved by using block transmission technology and the dense coding method.Compared with the existing similar quantum key agreement protocols,the number of the used qubits and the number of the classical bits exchanged for decoding of the message are decreased,which greatly improves the qubit efficiency.2.Based on the collective noises and W-state,two multi-party quantum key agreement protocols are proposed.Firstly,the characteristics of the collective noises are analyzed.Secondly,based on the collective-dephasing noise and the collective-rotation noise,two multi-party quantum key agreement protocols are proposed by utilizing the characteristics of W-state.Finally,the efficiency of these two protocols are analyzed.By comparing with other multi-party quantum key protocols,these two multi-party quantum key protocols are efficient.3.Based on Bell and four-particle cluster states,by using the rotation operations,Controlled-Z gate(CZ),Controlled-NOT gate(CNOT)and unitary operations,two quantum key agreement protocols which can be immune to the collective-dephasing noise and the collective-rotation noise are proposed.Security analysis shows that these two protocols can resist participant attack and outside attacks.By comparing with the proposed two-party quantum key agreement protocol against the collective noises,the efficiency of our protocol are more efficient.