Secret Sharing Schemes—Constructions,Impementations And Information Rate

In this thesis,we study the construction, implementation and information rate of the secretsharing scheme.We show the secret sharing scheme for access structure based on the network isideal,and give out the algorithIn to implement the secret sharing scheme on the netWork,and onany graph. We propose a threshold scheme to identify cheaters, Whose properties are analysedin details. We illtroduce some constrUctive methods of computing the information rate,give outthe upper bound of the optimal information rate and the optimal average information rate of thekind of access structure with special properties.We discuss the infOrmation rates of trees,give outthe iallmum on the optimal information rates,obtain the necessary and sufficient conditionsunder which the optimal infOrmation rates of trees equal 2/3,and show that the values of theoptimal infOrmation rate should not be in the interval (3/5,2/3).Lastly, We give out the definitelvalue of the optimal infOrmation rate of two kinds of sPecial trees.