Blockchain-based mobile crowdsourcing model with task security and task assignment

Crowdsourcing is a task assignment technology that has emerged in recent years, enabling companies to reduce costs and increase work efficiency. Most of the current crowdsourcing systems (BCSs) built on blockchain focus on solving privacy issues and use rigorous proof protocols for task and solution security. Such systems cannot be directly applied in mobile environments because it would lead to excessive computational overhead for the endpoint. To achieve confidentiality of crowdsourcing tasks during transmission while reducing the energy consumption of mobile devices and optimizing task assignment results, in this paper, we develop a blockchain-based crowdsourcing model. We first build a model structure consisting of basic components, such as users, smart contracts, and blockchain, and design contracts to implement various crowdsourcing operations, such as registering, publishing tasks, and acquiring solutions. Unlike before, the ciphertext of the task and the encrypted secret key are embedded into the contract. This, together with the three operations we designed for users to interact with the smart contracts, can effectively protect the crowdsourcing data from being stolen while using the address anonymity of Ethereum to ensure the privacy of users. During task assignment, we use the DBSCAN algorithm to delineate each valid service area and implement the established multiobjective planning model within each area to achieve as many benefit goals as possible in the best way. Finally, we implement our prototype on the Ethereum test network Ropsten. The experimental results show that the cost overhead of the designed model is acceptable to mobile users, and the security analysis establishes the confidentiality of the designed operations.