🔐 CryptPe - Decentralized Hybrid Payment Gateway System

CryptPe is a decentralized payment gateway that bridges the gap between traditional UPI payments and blockchain-based cryptocurrency transfers. It leverages Ethereum smart contracts to record transactions securely while providing a React Native + Expo-based frontend that mimics the user-friendly flow of UPI apps.

---

📁 Project Structure

CryptPe/
├── app/
│ ├── (tabs)/
│ │ ├── _layout.tsx
│ │ ├── crypto.tsx
│ │ ├── index.tsx
│ │ ├── profile.tsx
│ │ └── upi.tsx
│ ├── _layout.tsx
│ └── globals.css
├── assets/
├── cache/
├── constants/
├── context/
│ └── TransactionContext.tsx
├── contracts/
│ └── TransactionHistory.sol
├── interfaces/
│ ├── interfaces.d.ts
│ └── Transaction.ts
├── node_modules/
├── scripts/
│ └── deploy.js
├── utils/
│ └── contract.ts
├── .env
├── app.json

---

🚀 Features

• 💳 Dual-mode payments (UPI and Crypto)
• 🔗 Ethereum-based smart contract transaction logging
• 📱 React Native + Expo frontend
• 📊 Transaction history pulled from blockchain
• ⚙️ Easy deployment and integration

---

🛠 Prerequisites

• Node.js & npm
• Hardhat (for smart contract deployment)
• Expo CLI (npm install -g expo-cli)
• Android emulator or Expo Go on mobile
• Metamask (for interacting with smart contracts)
• Ganache (or Hardhat node) for local blockchain

---

🧑‍💻 Setup Instructions

1. Clone the Repository

git clone https://github.com/gitgyana/CryptPe.git
cd CryptPe

2. Install Dependencies

npm install

⚙️ Blockchain Setup (Hardhat)

3. Run Local Hardhat Node

npx hardhat node

4. Compile the Contract

npx hardhat compile

5. Deploy the Contract

npx hardhat run scripts/deploy.js --network localhost

• Note: Copy the deployed contract address to .env file like this:
• NEXT_PUBLIC_CONTRACT_ADDRESS=0xYourDeployedContractAddress

📲 Running the App (Mobile)

6. Start the Expo App

npx expo start

• Scan the QR Code using Expo Go app on your Android device.
• Make sure your development machine and phone are on the same network.

---

🔗 How It Works

• upi.tsx and crypto.tsx send transaction metadata (amount, type, method) to TransactionContext.tsx
• The TransactionContext.tsx handles in-app state and can push to the blockchain via smart contracts.
• profile.tsx retrieves the transaction history directly from the smart contract (contract.ts) and displays it.

---

📜 Smart Contract

• Located in:

  • contracts/TransactionHistory.sol

• Handles:

  • Storing transaction metadata
  • Retrieving transaction count
  • Returning transaction data to the frontend

---

🧪 Testing

• Use Ganache or Hardhat node for local blockchain testing.
• Use Metamask with localhost chain ID 1337.

---

📌 Future Enhancements

• Real wallet integration (MetaMask/WalletConnect)
• NFT-based transaction receipts
• Push notifications for successful payments
• AR-based location tagging for real-world payments