# Securing Construction Workers' Data Security and Privacy with Blockchain Technology
## 3 Methodology
### Experimental Design of the Proposed Blockchain
#### 3.1.2 System Structure of Proposed Blockchain  
Figure 3 below shows the system structure for the proposed Hyperledger Fabric blockchain developed on AWS. The system structure was organized into five (5) layers to facilitate the functioning of the blockchain network. The layered structure can be described from bottom to top as follows:  
Figure 3: System structure for proposed Hyperledger Fabric blockchain. AWS Infrastructure Layer: This layer served as the foundational layer for the proposed blockchain system, and it was built using Amazon Web Services (AWS). It established a cloud computing platform for setting up and managing the network. This layer utilized various AWS components, like virtual machines, storage services, and networking resources. To ensure scalability, Auto Scaling was implemented, which dynamically adjusted resources as per demand. AWS's Elastic Cloud Compute (EC2) provided virtual servers for running applications. This infrastructure was created in the Asia Sydney AWS region on a Virtual Private Cloud (VPC) network to ensure network isolation and security for the blockchain network. An EC2 instance on the Ubuntu platform was set up within this network to establish a secure environment. This infrastructure configuration was designed to support the secure and efficient functioning of the blockchain system. Hyperledger Fabric Layer: This layer implemented the Hyperledger Fabric protocol, which is designed for secure and efficient permissioned networks. This layer consisted of various components, including 2 organizations, 1 Orderer node, 2 Peer nodes, 1 Certificate Authority (CA), a Membership service provider (MSP), the Channel, a Gossip, a LevelDB storage library, and blocks. In this blockchain framework, organizations represented stakeholders with authorized access, such as project managers, engineers, regulators, etc. Peer nodes were crucial for network maintenance, storing copies of the blockchain, participating in consensus, validating and sharing transactions, and upholding decentralization. These peers communicated to verify and synchronize data, thus ensuring the reliability of the distributed ledger. The Orderer node maintained transaction sequencing and consistency. It organized transactions into blocks, thus maintaining their chronological order and integrity. By broadcasting these blocks to peers, the Orderer enabled consensus on transaction validity and ensured a synchronized view of the blockchain across the network. Certificate Authorities (CAs) played a crucial role in establishing trust and verifying the identities of network participants. They issued digital certificates that linked public keys to specific identities, thus enabling authentication and secure communication. CAs managed certificates, verified identities, and ensured secure interactions and transactions, thereby enhancing network security and trust. Channels enabled secure and confidential communication and transactions between specific stakeholders. Private channels ensured data privacy and compliance with regulations, thus facilitating secure information exchange among relevant parties. The Gossip protocol facilitated peer-to-peer communication and data synchronization in the network. It efficiently disseminated information through interconnected peers, thus ensuring scalability and efficient communication. LevelDB, an open-source key-value storage library, was used to store and retrieve blockchain data efficiently. It provided a simple key-value data model, allowing users to insert, retrieve, and delete data based on unique keys. Blocks represented collections of transactions organized sequentially and added to the blockchain. They formed the fundamental units of the blockchain, encapsulating multiple transactions within a single entity. Integration Layer: The integration layer facilitated the integration of the blockchain network with external systems and services.