MediChain

MediChain is a blockchain-powered drug authenticity verification system that helps combat counterfeit medicines using Ethereum blockchain technology.

Overview

MediChain allows patients and pharmacies to verify medicines through a unique QR code printed on each package. The system uses smart contracts to track each drug's information and verification history.

Key Features

• QR Code Verification: Scan medicine QR codes to instantly verify authenticity
• Blockchain Security: All drug data is stored securely on the blockchain
• Counterfeit Detection: Alert system identifies suspicious verification patterns
• Trustless Verification: No need to trust a central authority

Local Development Setup

This guide helps you set up MediChain locally without requiring any external blockchain providers or wallets.

Prerequisites

• Node.js (v14 or later)
• npm or yarn

Installation

# Clone the repository
git clone https://github.com/HWKDS/MediChain.git
cd MediChain

# Install project dependencies
npm install

# Install Ganache for local blockchain
npm install -g ganache

.env configuration

THEREUM_NETWORK=local
PORT=5000
# Contract address (will be filled automatically by deploy_local.js)
CONTRACT_ADDRESS=

Deploy to Local Blockchain

1. Start a local blockchain using Ganache:

# Run Ganache with deterministic addresses
ganache --deterministic

2. In a new terminal, compile and deploy the smart contract:

# Compile the contracts
npx truffle compile

# Deploy using the local script
node scripts/deploy_local.js

The deployment script will:

• Deploy the MediChain contract to your local blockchain
• Register a test manufacturer
• Add a test drug with QR code "MED-12345"
• Update the .env files with the contract address

Start the Backend Server

cd medichain-backend

# Install dependencies (if not done already)
npm install

# Start the server
node server.js

The server will connect to the local blockchain and use the first Ganache account for transactions.

Start the Frontend Application

cd medichain-frontend

# Install dependencies (if not done already)
npm install

# Start the development server
npm start

The application should open in your browser at http://localhost:3000

Testing the Application

1. Verify the test drug:

   • Enter "MED-12345" in the verification field, or
   • Generate a QR code with text "MED-12345" and scan it using the app's scanner

2. Register additional drugs using the API:

curl -X POST http://localhost:5000/api/register \
  -H "Content-Type: application/json" \
  -d '{
    "qrCode": "MED-67890",
    "name": "AnotherDrug",
    "manufacturer": "OtherPharma",
    "batchNumber": "BATCH002",
    "manufactureDate": "2023-01-01",
    "expiryDate": "2025-01-01",
    "ingredients": "Active ingredients, excipients"
  }'

Architecture

MediChain consists of three main components:

1. Smart Contract: Stores drug information and handles verification logic
2. Backend API: Acts as a bridge between the frontend and blockchain
3. Frontend UI: User interface for scanning QR codes and displaying verification results

Troubleshooting

Common Issues

1. "Cannot read properties of undefined" errors:

   • Ensure Ganache is running with --deterministic flag
   • Check that the contract address in .env files matches the deployed contract

2. Transaction reverted errors:

   • Increase gas limit for complex transactions (usually 500,000 is sufficient)
   • Make sure you're using the authorized manufacturer account

3. QR scanner not working:

   • Ensure you've granted camera permissions
   • Use a well-lit QR code
   • Try entering the code manually if scanning fails

Restarting the Project

If you encounter persistent issues, try these steps:

1. Restart Ganache with a clean state:

   ganache --deterministic --clear

2. Redeploy the contract:

   node scripts/deploy_local.js

3. Restart the backend and frontend servers

Project Structure

• /contracts: Solidity smart contracts
• /migrations: Truffle migration scripts
• /medichain-frontend: React frontend application
• /medichain-backend: Express.js backend API
• /scripts: Deployment and utility scripts

Future Enhancements

• Mobile application for easier verification
• Integration with pharmaceutical supply chain systems
• Multi-factor authentication for manufacturers
• Analytics dashboard for monitoring drug verifications