A Decentralized Task Validation Protocol for Blockchain-Based Crowdsourcing Using Smart Contracts

Alipour Shahraki, Mohammad; Noorbehbahani, Fakhroddin

doi:10.22042/isecure.2025.521116.1224

A Decentralized Task Validation Protocol for Blockchain-Based Crowdsourcing Using Smart Contracts

Document Type : Research Article

Authors

Mohammad Alipour Shahraki

Fakhroddin Noorbehbahani

Department of Information Technology Engineering, Faculty of Computer Engineering, University of Isfahan, Isfahan, Iran.

10.22042/isecure.2025.521116.1224

Abstract

Ensuring fair task validation and reward distribution remains a significant challenge in decentralized crowdsourcing systems. Existing platforms often suffer from malicious evaluations, unfair compensation, central points of failure, and limited transparency. In this work, we propose a fully decentralized crowdsourcing protocol built on blockchain technology and smart contracts to address these issues. Our system introduces a validator-based task evaluation process and ensures secure and private task handling through encryption and decentralized IPFS storage. Participants interact through smart contracts, which manage task assignment, output verification, and automated reward distribution. To promote fairness, we employ a reward allocation strategy based on the actual contribution of each participant. The proposed system addresses critical crowdsourcing challenges including malicious or biased evaluations, Sybil attacks, collusion, single points of failure, lack of revision mechanisms, and excessive transaction costs. Experimental results show that our smart contracts are executed with low cost (total deployment cost of 0.0511 ETH, with function calls as low as 47,878 gas units). The system sustains reliable operation and maintains integrity even when adversarial validators control up to 49% of the total reputation.

Keywords

Crowdsourcing

Blockchain

Tasks Validation

Reward distribution

Smart Contract

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