Building a Decentralized Crowdsourcing System with Blockchain as a Service

The conventional crowdsourcing system is dependent on a centralized platform, which grants the platform owner undue authority to manipulate the operation of the system for unethical profits. In this paper, the crowdsourcing system is revolutionized in a decentralized manner with Blockchain as a Service (BaaS). All crowdsourcing operations are implemented with smart contracts deployed on blockchain. Requesters invoke these contracts to publish tasks, while workers invoke them to submit solutions. Notably, the operation of assigning tasks is regarded as a crowdsourcing task to be performed by assigners. Multiple assigners compute respective task assignment schemes in an off-chain manner, and then submit the schemes to blockchain for competition. Performance evaluations show that not only the operating efficiency of the crowdsourcing system is improved, but also the adverse consequences of the system being maliciously manipulated are avoided. The proposed decentralized crowdsourcing system is anticipated to restructure the business model of the conventional crowdsourcing industry.

I. Introduction

Crowdsourcing is an efficient way of organizing labor by assigning tasks to dispersed workers over the Internet [1]. Some companies have reconstructed traditional business models with crowdsourcing for data labeling, ride sharing, delivering, etc., and have achieved great commercial success [2]. But crowd-sourcing, as a way to integrate crowd intelligence or labor to perform tasks, relies on a centralized service platform, which raises some serious questions [3], [4].