Design And Analysis Of Quantum Secret Sharing Protocols In Noisy Environment

In today's society where information is increasingly interconnected,the transmission,storage,and processing of massive amounts of information face the risk of leakage.The emergence of quantum computer prototypes poses a threat to the security of classical cryptosystems based on mathematical complexity.In recent years,communication technology based on the principles of quantum mechanics has achieved a breakthrough in theories and experiments,providing technical guarantees against the hidden dangers of classical communication and cryptosystems.This dissertation focuses on quantum secret sharing in the field of quantum communication,including semi-quantum secret sharing based on multi-level quantum systems,and multi-party(dynamic)quantum secret sharing immune to collective noise as well as its noise simulations.The main research contents are as follows:1.A semi-quantum secret sharing(SQSS)scheme was designed by using two groups of orthogonal eigenstates in 3(4)-level quantum systems.Then,the specific cases of sharing keys and the method of generating keys under the L-level systems were given.Finally,the impact of the Intercept-measure-resend attack and the Entangle-measure attack on the scheme was discussed,and the amount of information shared by the SQSS in different levels of systems was compared.2.Based on the decoherence-free subspace(DFS),two multi-particle logical GHZtype states were constructed,and the corresponding preparation methods were given using controlled quantum gates.Subsequently,following the discussion of the measurement correlation characteristics of the quantum state and logical Bell state,we proposed multiparty(dynamic)quantum secret sharing immune to collective noise.Finally,the security of the schemes was analyzed and comprehensively compared with the previous QSS from multiple perspectives such as qubit efficiency,quantum channel,and the measurement method.3.Two kinds of 7-particle logical ?-type entangled states were constructed based on DFS,and the corresponding quantum generation circuits were given through the experimental feasible local quantum gates.Following that,the entangled states were used as the quantum channel to study the four-party sharing schemes of any single(two)-quantum state immune to collective-dephasing(rotation)noise,in which the sender and other participants transfer shared information through different projective measurements.For different collapse cases of the designated receiver's particle systems,there were corresponding combinations of recovery unitary operators,that is,the schemes can reconstruct the shared state with 100% probability.4.The amplitude damping noise and depolarizing noise were used to simulate the proposed single quantum state sharing schemes immune to collective-dephasing(rotation)noise,and the relationship between the fidelity of the two schemes and the noise parameter and the coefficients of the single quantum state was discussed.Finally,and the parameter values of the optimal fidelity were obtained with the help of numerical simulation.