🍃 GreenGait 🍃

GreenGait is a Web3 rewards platform that transforms physical activity into real digital value using the Solana blockchain. With a secure, Wi-Fi-enabled wearable device (ESP32), every step you take is cryptographically signed and submitted to the blockchain – all in real time. 🏃 + ✅ → 💰 on-chain.

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Table of Contents 📁

1. Architecture Overview
2. Features Implemented
3. Security Architecture
4. Project Structure
5. Example Flow
6. How to Run Locally
7. What's Next?
8. Author

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🌐 Architecture Overview

🔹 ESP32-WROOM-32D A microcontroller that simulates steps via a button. Sends step data via MQTT over TLS using mutual certificate authentication.

🔐 TLS Mutual Authentication Secure communication using custom client certificates and a trusted CA, protecting against unauthorized devices.

🧠 Rust Backend Validator Receives messages via MQTT, validates authenticity (HMAC + timestamp), then logs valid steps on-chain via a Solana smart contract.

⛓️ Solana Anchor Program Deployed on Devnet. Uses Program Derived Addresses (PDAs) to store step data per user per day. Tokens are minted automatically every 3 steps.

📡 EMQX Broker (Google Cloud VPS) A hardened MQTT broker with TLS, ACL rules, and certificate-based access control.

🖥️ Frontend Interface Visualizes your step history and blockchain rewards in a simple dashboard.

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✅ Features Implemented

• ✅ ESP32 device with WiFi + MQTT + TLS client auth

• ✅ TLS mutual authentication via custom certificates

• ✅ HMAC-SHA256 signature generation on device

• ✅ JSON payload with: steps, timestamp, nonce, signature

• ✅ Rust backend:

  • MQTT TLS client
  • HMAC & timestamp validation
  • PDA-based step tracking and token minting

• ✅ Solana Anchor program with log_step instruction

• ✅ Solana Devnet deployment and testing

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🔐 Security Architecture

• HMAC-SHA256 signed payloads (shared secret)
• Timestamp validation to prevent replay attacks (±30s)
• TLS mutual authentication (ESP32 ↔ EMQX ↔ backend)
• EMQX Broker enforces certificate-based access and ACL rules
• Backend runs on a hardened Google Cloud VPS with TLS
• PDA ensures unique, tamper-proof on-chain logs per (user, day)

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📁 Project Structure

GreenGait/
├── backend/              # Rust backend (MQTT client, validation, blockchain interaction)
├── solana_program/       # Anchor smart contract + TypeScript tests
├── solana/               # CLI scripts, account utilities, program deploy
├── frontend/             # (WIP) UI for displaying step history and rewards
├── firmware/             # ESP32 Arduino code (WiFi, MQTT, HMAC)
├── docs/                 # Arch-Diagram + PPT Presentation + Logo
└── README.md             # You're here!

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🔁 Example Flow

1. Press the button → ESP32 sends a signed JSON payload
2. EMQX broker securely forwards it to the backend
3. Backend verifies the HMAC + timestamp → logs it on-chain
4. If steps are divisible by 3, a token is minted
5. Frontend displays user stats (WIP)

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🛠 How to Run Locally

1. Flash the ESP32

Upload ESP32.ino from firmware/ using Arduino IDE. Make sure certificates.h contains:

• ca.crt
• client.crt
• client.key

2. Start the Rust Backend

cd backend
cargo run

Make sure these files exist in certs/:

ca.crt
client.crt
client.key
stepmint-validator.json (Solana keypair)

3. Run the Solana Tests

cd solana_program
anchor build
anchor test

Tests

4. Deploy the Solana Program

anchor deploy

Deploy

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🌟 What's Next?

• 🧠 PDA optimization
• 💎 NFT/token design for major milestones
• 🎨 Dashboard UI with wallet connection and real-time stats
• 🔄 ESP32 OTA firmware delivery
• 🛡️ Replay prevention & abuse detection
• 🔋 Connection with energy harvesting system
• 🛰️ GPS Accuracy
• 🗄️ User Database

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👤 Author

Robert Panța

MSc Student in Cybersecurity at Technical University of Cluj-Napoca

• 📧 LinkedIn
• 🌐 GitHub

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🍃 GreenGait – where every step counts… on-chain, securely, and sustainably.