🔗 DocChain - Multi-Role Document Verification System

A complete blockchain-based document verification system with role-based access control, IPFS integration, and visual workflow.

🎯 System Overview

DocChain is a decentralized application that handles digital certificate generation and verification processes using blockchain technology, IPFS storage, and QR codes.

🎭 User Roles

• 👑 Owner: System administrator who verifies universities and companies
• 🎓 Student: Upload documents for university verification
• 🏛️ University: Verify student documents (requires owner approval)
• 🏢 Company: Check document authenticity (requires owner approval)

✨ Key Features

• 🔐 Multi-role access control with blockchain-based permissions
• 📄 Document hash verification using SHA-256 + IPFS
• 🎨 Visual workflow interface with step-by-step process
• 📊 Progress indicators for file uploads
• 🌐 IPFS integration for decentralized file storage
• 🔍 Real-time verification status tracking
• 📱 Responsive design for all devices
• 🎯 Batch document processing for universities
• 🔗 QR code integration for easy verification

🚀 Quick Start

Prerequisites

• Node.js v16+
• MetaMask browser extension
• Git

Installation

# Clone repository
git clone https://github.com/Nish12345944/DocChain.git
cd DocChain

# Install all dependencies
npm run install-all

Local Development

# Terminal 1: Start blockchain
npm run start-blockchain

# Terminal 2: Deploy contract
npm run deploy-local

# Terminal 3: Start frontend
npm run start-frontend

MetaMask Setup

1. Add Hardhat Local Network:

   • Network Name: Hardhat Local
   • RPC URL: http://127.0.0.1:8545
   • Chain ID: 31337
   • Currency: ETH

2. Import Test Account:

   Private Key: 0x59c6995e998f97a5a0044966f0945389dc9e86dae88c7a8412f4603b6b78690d
   

3. Access Application:

   • Open: http://localhost:3008
   • Connect MetaMask
   • Start testing!

📋 Usage Workflow

1. Owner Setup

• Use Account #0 (contract owner)
• Verify university and company registrations

2. Student Journey

• Register as Student (auto-approved)
• Upload documents with visual workflow:
  • Step 1: Select and process file
  • Step 2: Choose university
  • Step 3: Submit to blockchain
• Grant company access to documents

3. University Process

• Register as University
• Wait for owner approval
• Verify student documents by comparing file hashes
• Batch process multiple documents

4. Company Verification

• Register as Company
• Wait for owner approval
• Verify documents by:
  • File upload (hash comparison)
  • QR code scanning
  • Document ID lookup

🏗️ Architecture

DocChain/
├── blockchain/                 # Smart contracts & deployment
│   ├── contracts/
│   │   └── DocChain.sol       # Main contract with multi-role system
│   ├── scripts/
│   │   └── deploy.js          # Deployment script
│   └── hardhat.config.js      # Hardhat configuration
├── frontend/                   # React application
│   ├── src/
│   │   ├── components/        # UI components
│   │   │   ├── StudentDashboard.js
│   │   │   ├── UniversityDashboard.js
│   │   │   ├── CompanyDashboard.js
│   │   │   ├── OwnerDashboard.js
│   │   │   ├── FileUpload.js
│   │   │   └── RoleRegistration.js
│   │   ├── utils/             # Utility functions
│   │   │   ├── contract.js    # Contract interaction
│   │   │   ├── crypto.js      # Hash calculations
│   │   │   ├── ipfs.js        # IPFS integration
│   │   │   └── wallet.js      # Wallet connection
│   │   └── App.js             # Main application
│   └── package.json
└── README.md

🛠️ Technology Stack

• Frontend: React 18, CSS3, Responsive Design
• Blockchain: Solidity ^0.8.20, Hardhat, Ethers.js v6
• Storage: IPFS for files, Ethereum for hashes
• Wallet: MetaMask integration
• Security: SHA-256 hashing, Role-based access control

📊 Smart Contract Features

// Multi-role system
enum UserRole { None, Student, University, Company }

// Document structure with dual hashes
struct Document {
    uint256 documentId;
    address studentAddress;
    string documentHash;    // SHA-256 of file
    string ipfsHash;       // IPFS CID
    address universityAddress;
    VerificationStatus status;
    uint256 timestamp;
    mapping(address => bool) companyAccess;
}

🌐 Deployment

Testnet Deployment (Sepolia)

# Update .env with your keys
SEPOLIA_URL=https://sepolia.infura.io/v3/YOUR_PROJECT_ID
PRIVATE_KEY=your_private_key_here

# Deploy to testnet
npm run deploy-sepolia

# Build frontend
npm run build-frontend

Production Deployment

1. Smart Contract: Deploy to Ethereum mainnet
2. Frontend: Deploy to Vercel/Netlify
3. IPFS: Use Pinata or dedicated IPFS node

🧪 Testing

# Run smart contract tests
npm test

# Test different roles
# 1. Register as Student (Account #1)
# 2. Register as University (Account #2) 
# 3. Owner approves University (Account #0)
# 4. Student uploads document
# 5. University verifies document
# 6. Company checks verification

📱 Screenshots

Student Dashboard

• Visual workflow steps
• File upload with progress
• Document management

University Dashboard

• Pending document verification
• Batch processing tools
• Hash comparison interface

Company Dashboard

• Document verification by upload
• QR code scanning
• Verification status display

🔒 Security Features

• Immutable Records: All verifications stored on blockchain
• Hash Verification: SHA-256 ensures document integrity
• Access Control: Role-based permissions
• Decentralized Storage: IPFS prevents single point of failure
• Transparent Process: All actions are publicly verifiable

🤝 Contributing

1. Fork the repository
2. Create feature branch (git checkout -b feature/AmazingFeature)
3. Commit changes (git commit -m 'Add AmazingFeature')
4. Push to branch (git push origin feature/AmazingFeature)
5. Open Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• OpenZeppelin for secure smart contract libraries
• Hardhat for development framework
• IPFS for decentralized storage
• React community for UI components

📞 Support

For support, email: support@docchain.dev or join our Discord community.

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Built with ❤️ using React, Solidity, and Ethereum