Blockchain-Based Secure Document Storage: Computer Engineering Guide
1. Introduction
Overview of the project.
Objectives of the system: Provide a secure, decentralized platform for document storage and retrieval.
Scope of the system: Suitable for applications like legal documents, academic certificates, and confidential business records.
2. Requirements Analysis
Functional Requirements:
· - Upload and store documents securely on the blockchain.
· - Provide document access based on user permissions.
· - Ensure immutability and transparency for audit purposes.
· - Enable document versioning and retrieval of historical data.
Non-Functional Requirements:
· - High availability and reliability.
· - Scalability to support large-scale usage.
· - Efficient storage and retrieval processes.
3. System Design
Architecture:
· - Blockchain-based decentralized architecture.
· - Use of InterPlanetary File System (IPFS) for off-chain storage of large files.
· - Smart contracts for access control and transaction management.
Data Flow Diagrams (DFDs):
· - Level 0: Overview of interactions between users, blockchain, and IPFS.
· - Level 1: Modules such as Document Upload, Access Request, and Audit Log.
Database Design:
· - Tables: Document Metadata, User Permissions, Access Logs.
4. Technology Stack
Blockchain Platform:
· - Ethereum, Hyperledger Fabric, or Polygon.
Storage Solution:
· - IPFS or AWS S3 for off-chain storage.
Smart Contracts:
· - Written in Solidity or other blockchain-specific languages.
Frontend:
· - Web application using React.js or Angular.
Backend:
· - Node.js or Python for server-side operations.
Database:
· - Off-chain metadata storage using MongoDB or PostgreSQL.
5. Implementation
Blockchain Setup:
· - Deploy a private or public blockchain network.
· - Write and deploy smart contracts for document management.
Frontend Development:
· - Create a user-friendly interface for document upload, retrieval, and permission management.
Backend Development:
· - Develop APIs for interaction with the blockchain and IPFS.
· - Implement authentication and access control mechanisms.
Integration:
· - Link blockchain, IPFS, and backend services for seamless operation.
6. Security
Ensure secure key management for blockchain access.
Encrypt documents before uploading to IPFS.
Implement role-based access control using smart contracts.
Regular audits to identify and fix vulnerabilities.
7. Testing
Unit Testing: Validate individual components such as smart contracts and APIs.
Integration Testing: Ensure seamless interaction between blockchain, IPFS, and other components.
System Testing: Test the entire system under real-world scenarios.
Performance Testing: Evaluate system performance with large-scale data.
8. Deployment
Deploy smart contracts on a blockchain network.
Configure IPFS nodes for off-chain storage.
Host the frontend and backend on a cloud platform like AWS or Azure.
9. Maintenance and Updates
Regularly update smart contracts for enhanced functionality.
Monitor blockchain network health and node synchronization.
Collect user feedback and implement feature improvements.
10. Appendix
Glossary of terms.
References and additional resources.