2.1.1. Framework Overview

In order to present services based on a fine-grained and data-sharing structure, the transactions saved in the blockchain database based on the privacy level have been classified. The level of privacy contains community data, encrypted data, and public data. Public data, here, refer to a datum which is able to be observed through entire nodes. In addition, community public data give information which is able to be recognized through entire nodes pertaining to the similar community, and encrypted information basically refers to the private data and those which users are willing to purchase/sell.

In general, when users share professional information, it is suggested that they adjust the amount of information privacy on public data in the community so that this information is shared by more users who actually access it, and that need it to be visible. As a result, the main purpose can be to apportion the community reasonably through gaining a community diagnosing technique so that the public information of the community is able to be divided between more users who actually require it. Figure 1 depicts the data-sharing structure according to the blockchain method. We have three different layers in our presented data-sharing strategy, such as Data Layer, Blockchain Layer, and Detection Layer. Information is gathered by the Data Layer and sent to the Detection Layer. The Detection Layer implements a community detection technique that divides customers into various communities and limits the domain of data sharing. The Blockchain Layer also has the responsibility of keeping the result of community detection and transaction records secure.

**Figure 1.** The data-sharing structure according to the blockchain technology.

## 2.1.2. Data Layer

The Data Layer contains data perceived through large-scale sensors [40] such as product type and product quantity, device performance status, and other data of several parameters.

Perception data are obtained by sensors and uploaded to the client server for comprehensive analysis and sharing. Perception information, after being obtained from the sensors, is sent and shared on the client's server for analysis.
