Research On Dynamic Adjustment Mechanism Of Security And Complexity Of Secure Multiparty Computation Protocol

With the development of information technology, cooperative computation and its security property have been paid more and more attention. So Secure Multiparty Computation become one of the hot research topics. In the relative performance of protocols and algorithms of Secure Multiparty Computation, security property and complexity property are two important factors. During the study of Secure Multiparty Computation, security property is mainly used to measure the leakage of information, and the complexity property is mainly used to measure computation cost and communication cost of protocol.Existing research of SMC all emphasized that the input information of participants is zero information leakage, in order to reach the ideal condition, the cost of computation and communication are all high. Although that security can reach the ideal condition is better, in practice, the cost of implementation is costly, and this isn't often feasible. But if want to improve efficiency, there must be some leakage of information. Some leakage of information isn't feasible for incredible users, but some users are credible in SMC. So, this thesis mainly study on dynamic adjustment mechanism of security and complexity of Secure Multiparty Computation protocol. In order to implement the dynamic adjustment mechanism of security and complexity, we study the quantitative methods of security and complexity,and study the method of determining the security level.Firstly, this thesis study the quantitative methods of security property and complexity property based on Scalar Product Protocol. Design the quantitative method of security property based on the relation between information leakage and security property. Because there is different models in Secure Multiparty Computation, in this thesis, two methods for security quantification have been designed. The first one is based on Scalar Product Protocol, and this method only fit for the case that only two or three participants in the SMC protocols, and the idea of the design depends on mapping function. The second method for security quantification is based on fuzzy theory, and this method can fit for number of participants in the SMC protocols.Secondly, design the determine method of security level according to the quantitative method of security property, design the method for complexity quantification based on the nature of complexity. Based on the methods of security quantification and complexity quantification, study the problem that is dynamic adjustment mechanism of security and complexity. Finally, according to the dynamic adjustment mechanism and the nature of the dynamic adjustment mechanism, analyze the application of the dynamic adjustment mechanism, and design the application program of dynamic adjustment mechanism.