Secure Multiparty Computation Problem

The proliferation of the Internet has triggered tremendous opportunities for cooperative computation, where people are cooperating with each other to conduct computation tasks based on the inputs they each supply. These computations could occur between trusted partners, between partially trusted partners, or even between competitors. Usually, to conduct these computations, one must know inputs from all the participants, but if nobody can be trusted enough to know all the inputs, privacy becomes a critical issue.Secure multi-party computation can be defined as the problem of n players to compute an agreed function of their inputs in a secure way, where security means guaranteeing the correctness of the output as well as the privacy of the players'inputs, even when some players cheat. Concretely, we assume we have inputs (x₁, …,x_n ) where player i knows x_i, and we want to compute f(x₁,…,x_n ) = (y₁x,…,y_n) such that player i is guaranteed to learn y_i but can get nothing more than that.Secure multi-party computation problem are discussed in this thesis.The basic theory of secure multi-party computation and some related knowledge have been introduced firstly. A protocol of secure Multi-party multiplication based on oblivioue transfer protocol and signcryption have been made secondly. We propose a new security paradigm for the secure multi-party computation studies— Secure multi-party computation of adjustable the security level thirdly. Instead of achieving the ideal security like most of the studies of SMC problems, we propose a different goal, to achieve acceptable (and adjustable)security. And we have developed some data disguising techniques of secure multi-party computation of adjustable the security level .including linear transformation disguise, (Z + V) -disguise and polynomial function disguise.In addition,we present protocols of several data disguising techniques and discuss their security and Complexity analysis. In this paper,we have gained the results in the following:1. We propose a multiplicative protocol of secure multi-party.2. we describe a new security paradigm for the secure multi-party computation studies-Secure multi-party computation of adjustable the security level.3. we have developed some data disguising techniques of secure multi-party computation of adjustable the security level .including linear transformation disguise,(Z + V) -disguise and polynomial function disguise.