###### Abstract  
With the arrival of the Internet of Things (IoT) era and the rise of Big Data, cloud computing, and similar technologies, data resources are becoming increasingly valuable. Organizations and users can perform all kinds of processing and analysis on the basis of massive IoT data, thus adding to their value. However, this is based on data-sharing transactions, and most existing work focuses on one aspect of data transactions, such as convenience, privacy protection, and auditing. In this paper, a data-sharing-transaction application based on blockchain technology is proposed, which comprehensively considers various types of performance, provides an efficient consistency mechanism, improves transaction verification, realizes high-performance concurrency, and has tamperproof functions. Experiments were designed to analyze the functions and storage of the proposed system.  
multilayer blockchain; massive IoT data; data sharing; transaction molding; hierarchical authorization +
Footnote †: journal: Medical  
they have with only a small trusted set of entities, because the CTI is owned by these entities. Finally, most current mainstream information systems are single-data-centered platforms, managed and maintained by third-party service providers. Data service providers become authentic data owners and can perform various operations on user-uploaded data. System users have become weak parties. Therefore, most current information systems cannot provide users with a guarantee of data reliability and privacy.  
The essence of this technology is decentralization that can reduce the value transfer cost and regulatory cost of traditional data-sharing platforms, and improve data reliability and transaction efficiency. Blockchain technologies offer new insight to data-sharing research. On the one hand, the application of blockchain technology in data-sharing-transaction scenarios can reduce the trust risk with decentralization, flatten the transaction process, and optimize the consensus algorithm to improve transaction efficiency. On the other hand, multiparty maintenance and distributed storage are the most distinctive blockchain features that can ensure data authenticity and reliability, and improve the credibility of data transactions.  
Although bitcoin [4; 5; 6; 7; 8; 9; 10; 11] and other blockchain application systems have been running on a global scale for a long time, and their technical value has been generally recognized, it is a pity that the function they support is still simple transactional data storage. Currently, there is no mature and stable blockchain system that can support massive data sharing on the Internet of things. Therefore, the processing capacity of blockchain technology in data-sharing applications of IoT devices needs to be improved, which is the main content of this paper.  
In order to solve the problem of data authenticity in a data-sharing-transaction scenario, it is difficult to guarantee the authenticity of the system, maintenance cost is high, and privacy is difficult to guarantee. This study proposes a multilayer blockchain model that supports massive data hierarchical authorization transactions, and applies blockchain technology to data-sharing transactions in the Internet of things to provide a secure and controllable data-exchange environment. This section first introduces the architecture of the data model. Second, we outline the design of the rights-management and identity-authentication mechanism to maintain privacy and security. Finally, we used the Interplanetary File System (IPFS) protocol to separate data transactions from file storage, which improved the operating efficiency of the whole system.