Decentralized Fair IoT Data Trading via Searchable Proxy Re-Encryption

The Internet of Things (IoT) is a network composed of information-gathering devices, sensors, and computing devices assembled in an intelligent manner, and the most important element in this system is data. IoT data trading plays a vital role in the area of personalized business nowadays. Individual IoT devices generate large amounts of private data, which data owners can sell to enterprises as important digital assets to make money, while enterprises collect IoT data to improve the accuracy of their services. Cloud storage services have been widely used in IoT data trading. In IoT data trading, cloud storage services have been widely used for individuals to store IoT data and for enterprises to automatically facilitate data trading. However, there are still two crucial drawbacks to be solved. From the point of security, it is difficult for data buyers to check the validity of the search result without getting the decryption key of the data owner. From the point of fairness, there is a lack of a punishment mechanism to transfer money from the cheating party to the honest party. To tackle the two challenges, we propose a searchable re-encryption scheme to maintain traditional security without sacrificing service quality. Next, we design a fair trading protocol based on smart contracts to automatically detect any cheating behaviors. Formal security analysis proves that the scheme provides expected security. Experimental results show that the scheme achieves good performance.