Abstract

The Internet of Things (IoT) is now used by people, homes, transportation, hospitals, and more, and the data collected from IoT devices is more diverse and vaster. Online data trading or sharing systems are evolving to use this data to create new value or utilize it for financial gain. Traditional online data trading systems rely on trusted third parties to ensure fair trading. However, these centralized trading systems suffer from various problems such as single point of failure and data leakage. Therefore, in this paper, we propose a blockchain-based fair data trading model that does not rely on a fixed trust factor and supports bilateral access rights management. The proposed model is designed in a hybrid way that combines on-chain and off-chain processes to minimize the storage space and performance limitations of the blockchain. Instead of relying on a fixed trust factor such as a trusted third party, we randomly select arbiter nodes during each data trading process, which provides higher decentralization than existing approaches. It also provides data confidentiality by ensuring bilateral access control and provides security in the dispute resolution process. Finally, smart contracts in the proposed model perform only simple computations, resulting in lower overhead and higher efficiency than existing models.