Blockchain Transaction System with Multi-Factor Login

A secure, full-stack crypto trading platform that demonstrates how blockchain technology and multi-factor authentication (MFA) can be combined to ensure transactional integrity and user protection. This project simulates ETH trading on the Ethereum blockchain using signed raw transactions while enforcing OTP-based login to guard against unauthorized access.

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🚀 Overview

This system allows users to:

• Register with a unique Ethereum address and private key
• Log in using multi-factor authentication (OTP)
• Buy and sell ETH with USDT (virtual)
• Execute real ETH transfers on a local blockchain (Ganache)
• Sign transactions with private keys (no unlocked accounts)
• View and sync ETH balances directly from the blockchain

All actions are logged, validated, and securely managed via smart transaction flows and server-side protection.

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🔐 Key Features

Feature	Description
🔗 On-Chain ETH Transactions	Real ETH transfers using eth_sendRawTransaction, signed with user's private key
🔑 Multi-Factor Authentication	Secure OTP-based login via email using PHPMailer
🔐 Private Key Isolation	Each user has their own Ethereum keypair; no keys are exposed or reused
🔄 Live Blockchain Balance Sync	ETH balance fetched from Ganache using eth_getBalance and stored in SQL
🧠 Smart Validation	All balances, OTPs, and blockchain state transitions are validated in PHP

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🛠️ Tech Stack

• Backend: PHP (with Composer), MySQL

• Blockchain: Ganache CLI (Ethereum test network)

• Libraries:

  • web3p/web3.php
  • web3p/ethereum-tx
  • PHPMailer

• Frontend: HTML, CSS

• Server: XAMPP / Apache (localhost)

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🧰 Folder Structure

project-root/
├── backend/
│   ├── buy_sell.php
│   ├── get_balance.php
│   ├── send_otp.php
│   ├── verify_otp.php
│   └── vendor/ (Composer libraries)
├── frontend/
│   ├── login.php
│   ├── register.php
│   ├── dashboard.php
│   └── index.css
├── database/
│   └── crypto_transaction.sql
├── .gitignore
├── README.md

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⚙️ Setup Instructions

1. Start Ganache CLI (with deterministic accounts):

   ganache-cli -d

   ➤ Download: Ganache CLI

2. Install PHP Dependencies via Composer

   composer install

   ➤ Download: Composer

3. Import SQL Schema Use phpMyAdmin or CLI to import database/crypto_transaction.sql into MySQL.

4. Configure Email OTP Set up email credentials in send_otp.php using PHPMailer. ➤ Download: PHPMailer GitHub

5. Run on Localhost Serve the project using XAMPP or any local Apache server:

   http://localhost/crypto_transaction/
   

6. Register → OTP Login → Trade

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📄 Security Architecture

• ✅ Blockchain signing: Private key used to sign ETH transactions with ethereum-tx
• ✅ No unlocked accounts: Ganache is accessed via raw RPC only
• ✅ MFA enforced: OTP sent via email is required to access user dashboard
• ✅ SQL Sanitization: All queries prepared with bound parameters
• ✅ Balance integrity: All ETH balances are fetched from Ganache, not faked

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🧑‍💼 Ideal For

• Blockchain Developer portfolios
• Backend Engineer job applications
• Demonstrating system security knowledge (MFA, wallet isolation, key signing)
• Students applying for crypto/web3 internships or junior dev roles

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📜 License

This project is open-source under the MIT License. Feel free to fork, customize, and contribute.

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🌐 Related Project

You can also view the initial version of this platform (focused on basic web programming) here:

🔗 Crypto Trading Simulator – Web Programming Version