An Implementation of a Blockchain-based Data Marketplace using Geth

Nowadays data is one of the most important assets that can be obtained, as many applications rely on data to generate useful services. However, a very few number of companies control, in a centralized manner, a large portion of data. That, combined with inefficiencies in centralized storage and recent data leak scandals, highlights the need for new ways in which data is shared and consumed, in which privacy and access control is guaranteed by design. Based on that, in this paper we present an implementation of a blockchain-based data marketplace utilizing the Go Ethereum (Geth) library. The implementation consists of an IoT node powered by a raspberry pi zero W, which is utilized to collect data from the environment and store it in an InterPlanetary File System (IPFS) external server, a web page that displays the marketplace, and a private blockchain that records transactions. Regarding the private blockchain, three smart contracts are developed in order to: 1) record information about the data in the marketplace; 2) record transactions that occur between users; 3) allow sellers to white/blacklist buyers' access to the data. This implementation shows that a decentralized blockchain-based marketplace is feasible and scalable, and we hope it can serve as an early model for future frameworks.