# A Blockchain-Based Supervision Data Security Sharing Framework
## 5 Discussion  
Engineering construction supervision has the characteristics of multiple participants, a large amount of supervision data, and high difficulty in information control. If blockchain technology is directly used to build a supervision data-sharing platform, issues such as blockchain data storage pressure, data-sharing privacy, consensus algorithm scalability, and performance will become the main technical bottlenecks [38]. This article proposes a blockchain-based framework for the secure sharing of engineering supervision data, by combining it with the IPFS to achieve the large-scale storage of engineering supervision data. A data fast retrieval framework is designed based on the storage characteristics of engineering supervision data. And CP-ABE is combined with smart contract technology to achieve access control in fine-grained privacy protection scenarios, and then smart contracts required for engineering supervision data-sharing applications are designed. Finally, the security, encryption and decryption, and cost performance of the framework are analyzed and evaluated. The experimental results show that the proposed framework in this paper solves the trust problem between various parties in engineering supervision data sharing, effectively meets the security requirements of engineering supervision data sharing, ensures the traceability of the engineering supervision data-sharing process, and has good usability and reusability. The engineering supervision data security sharing system is mainly applied in the consortium chain network environment, including the IPFS network for storing metadata off chain and the consortium chain network for storing summary information on chain. By sharing engineering supervision data, each block node of the supervision party supervises each other and jointly maintains the security and consistency of the on-chain engineering supervision data, achieving efficient and standardized management of engineering supervision data and secure sharing applications. Therefore, by combining the application scenario of blockchain engineering supervision data sharing, this article proposes a secure sharing application architecture for engineering supervision data based on a consortium chain, as shown in Figure 4. The architecture mainly includes five layers: application layer, contract layer, interface layer, consortium chain service layer, and data storage layer. Relevant application research and development can be carried out based on this architecture. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Frame**} & \multirow{2}{*}{**Blockchain Type**} & **User Level Access Control Granularity** & \multirow{2}{*}{**Data Privacy**} & \multirow{2}{*}{**Computing Power Requirement**} \\ \hline Reference [37] & Consortium blockchain & No & No & High \\ Reference [18] & Consortium blockchain & No & No & Low \\ Proposed framework & Consortium blockchain & Yes & Yes & Low \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Comparison between the proposed framework and existing frameworks. 1. Application layer. This layer refers to the application implementation of establishing a data-sharing system based on blockchain, which implements transaction functions in the form of client operations. Depending on the permission settings, users can complete operations such as uploading, querying, and downloading supervision data through the client. 2. Contract layer. This layer is the technical layer that enables data sharing and transactions on the blockchain network, including data uploading, querying, and user access control, while being able to manage the deployment and execution of smart contracts. This contract combines the sharing requirements of supervision data, implements access control for the sharing process, and completes the spontaneous operation management of supervision data sharing. 3. Interface layer. The function of this layer is to connect the blockchain network and clients.