Research And Application Of Secure Multi-party Computation Based On Blockchain

The development of information technology has brought great convenience to our lives,but traditional centralized institutions and applications keep collecting personal data to provide more refined and personalized services,which also raises people's concern about the leakage of personal privacy.How to realize joint computing of data while protecting privacy has become a research focus in the fields of information science and cryptography.Both secure multi-party computation and blockchain mainly deal with the trust and security issues in distributed environments.Blockchain can better meet the needs for privacy data protection with the help of secure multi-party computation,and to be applied to more scenarios.Secure multi-party computation can use the blockchain to obtain the characteristic of public verifiability to ensure the security and credibility of the calculation results.The combination of secure multi-party computing and blockchain can effectively solve the problems of inequality and opaqueness in traditional centralized systems,allowing data to truly circulate and generate greater value.At present,the research of secure multi-party computation based on blockchain mainly focuses on fairness and computation protocol.Focusing on the problem of privacy protection on on-chain collaborative computation.This article mainly carried out the following work:1.At present,the secure multi-party computation protocol based on blockchain still has the problem of not being practical or relying on additional security assumptions.This article,therefore,proposes a secure multi-party computation protocol for permissioned blockchain(BTSMPC),which supports both addition and multiplication operations.The protocol adopts a phased execution method to reduce the cost of on-chain calculations.and uses the method of performing computation on ciphertext fragmentation to protect the privacy of the input data and realize the controllable privacy on blockchain.The protocol is able to ensure that the entire calculation process is public and verifiable.A trust evaluation mechanism that takes the current and historical behaviors of each participant into consideration is introduced into the proposed secure multi-party computation protocol.The mechanism provides an evaluation method of the trust degree of participants and combines the deposit mechanism to force participants to perform the protocol correctly,which ensures the fairness of the proposed protocol.What's more,the article describes how the proposed secure multi-party computation protocol be integrated into Hyperledger Fabric,and explains how the solution resists invalid requests and malicious requests,and prevents the problems of data tampering.The comparative analysis shows that the proposed BTSMPC protocol has better security and practicability,and the experiments show that the protocol has has good execution efficiency in permissioned blockchains.2.In view of the fact that the existing electronic voting scheme has the problem of relying on trusted institutions,based on the proposed BTSMPC protocol,a new weighted anonymous electronic voting protocol is proposed.The blockchain is used to replace traditional ticket centers and supervisory agencies,and plays the roles of voting,checking ballot,counting ballot,and other processes.The protocol greatly guarantees the anonymity of votes and counting votes.Compared with the existing blockchain-based electronic voting scheme,the proposed protocol has better practicability and security.Finally,the article implements a complete electronic voting system based on the proposed electronic voting protocol to verify the validity and practicability of the proposed electronic voting protocol and secure multi-party computation protocol.