Research And Implementation Of Trusted Crowdsourcing Mechanism Based On Blockchain Smart Contract

Crowdsourcing is a distributed problem-solving mechanism and an emerging business model.Because it often involves reliance on crowdsourcing platforms and thirdparty agencies for salary delivery,existing platforms face many problems such as being maliciously attacked,malicious contractors,and malicious contractors participating in the system in actual operation.In general,the core contradiction in the protection of multiparty interests in crowdsourcing activities lies in how to establish the multi-party trust of the recipients and the contractors in the platform in an open Internet environment,and improve the quality of crowdsourcing tasks.Aiming at the rights protection problems existing in the existing technologies,blockchain and smart contract technologies have brought new solutions to the rights protection of crowdsourcing activities.This thesis aims to use the advantages of blockchain technology and smart contracts in confirming rights,preserving evidence,and traceability to design a safe,fair and reliable smart contract-based crowdsourcing activity monitoring method and system DCrowd.The contributions of this thesis are as follows:1.A two-phase commit mechanism and unbiased random selection algorithm based on commitment protocol are proposed.As the premise of obtaining credible crowdsourcing results,credible submission of data and a fair selection of recipients play an important role.This thesis firstly uses the open,transparent,and non-tamperable technical characteristics of the blockchain to design a two-stage publishing mechanism for on-chain data based on commitment protocol,TPReview,and apply it to the submission process of crowdsourcing result data,effectively ensuring that each Information independence and credibility between the recipients,and avoid the "plagiarism" phenomenon of the recipients.Secondly,based on TPReview,this thesis designs an unbiased random selection algorithm,TPSortition,for DCrowd to select independent receivers from the decentralized receiver library to avoid possible unfairness and collusion.In addition,this thesis also designs asymmetric encryption,task segmentation,and other means to protect the crowdsourcing task publishing process,which effectively ensures the privacy of crowdsourcing task data.2.An incentive mechanism design based on game theory is proposed.Earning income is the original motivation for the recipient to complete the crowdsourcing task,so this thesis carefully designs the incentive function:to obtain the maximum profit,the recipient must always answer honestly.This thesis analyzes the crowdsourcing scenario from the perspective of game theory,and transforms the incentive process of crowdsourcing tasks into the game activities of the contractors,thereby transforming the trust problem into an economic problem.3.Design and implement a prototype system based on Ethereum smart contracts.This thesis implements the prototype system DCrowd using the smart contract of the Ethereum blockchain.DCrowd realizes core functions such as crowdsourcing user management,user reputation review,and crowdsourcing task management through the cooperation of multiple smart contracts.This thesis proves the feasibility of DCrowd by testing the "gas fee" of each interface in the contract and shows good performance that meets the design expectations.