Hybrid Blockchain Design for Privacy Preserving Crowdsourcing Platform

Blockchain has been treated as one of the most promising technologies to promote crowdsourcing by providing new nice features, such as decentralization and accountability. Unfortunately, some inherent limitations of blockchain have been rarely addressed by the most existing works when applying blockchain into crowdsourcing, which becomes the performance bottleneck of crowdsourcing systems. In this paper, we propose a novel hybrid blockchain crowdsourcing platform to achieve decentralization and privacy preservation. Our platform integrates with a hybrid blockchain structure, dual-ledgers, and dual consensus algorithms to ensure secure communication between the requesters and the workers. Moreover, the smart contract and zero-knowledge proof are employed to ensure automatic operation of the tasks and the protection users' privacy, respectively. Finally, we conduct experiments to confirm the efficiency of the adopted consensus algorithm on our platform by comparing it with the state-of-the-art.

I. Introduction

Crowdsourcing that outsources tasks to a non-specific, and usually large, mass network has already been popular and widely applied for years [1]. A typical example is Wikipedia, which allows everyone to join the platform and answer specific questions, and thus solving diverse customer needs [2]. Another application is Uber, which crowds the passengers' post and sends to the social idle drivers' clients [3]. Recently, Amazon also provides its crowdsourcing marketplace called Amazon Mechanical Turk (MTurk) to help companies to harness intelligence from a global view and enable workers to work on their interested tasks [4]. As an advanced paradigm, crowdsourcing is destined to have a bright future for important real-world applications.