Arduino-NFT-PUF

A joint project for the IoT Security and Data Security courses of the Master's Degree in Computer Science at the University of Salerno.

Overview

Arduino-NFT-PUF is an innovative approach to device fingerprinting and ownership verification by leveraging SRAM Physical Unclonable Functions (PUFs) and blockchain technology. This project enables unique identification of Arduino devices through their intrinsic hardware characteristics and secures ownership via Non-Fungible Tokens (NFTs).

This project is a proof of concept and is not intended for production use. It demonstrates how hardware-based security can be combined with blockchain technology to create a secure and verifiable ownership system.

Key Features

The project consists of three main components:

1. Arduino SRAM-PUF

• Physical Unclonable Function (PUF) implementation using the inherent randomness in SRAM startup values.
• A custom bootloader and data manipulation are required to obtain a stable PUF response.

2. NFT Smart Contract

• A simple NFT Smart Contract compliant with the ERC-721 standard.
• Links an Ethereum account to a PUF for ownership verification.
• Written in Solidity and tested on an Ethereum testnet using Hardhat.

3. DApp (Decentralized Application)

• A simple DApp to interact with the Smart Contract.
• Users can log in via MetaMask and mint NFTs through the app.
• Built using Web3.js for blockchain interaction.

Prerequisites

Hardware Requirements

• Two Arduino Uno R3 boards.
• 6 cables to connect the boards.
• A USB cable to connect the board to a PC.

Software Requirements

For the Arduino SRAM PUF:

• Arduino IDE
• avrdude
• avr-gcc
• scons
• minicom

For the NFT Smart Contract:

• Hardhat (for testing on a testnet)
• Solidity

For the DApp:

• JavaScript
• Web3.js

Important Notes

• Arduino as ISP: Works on Arduino Uno R3 boards. Tested on Arduino Uno R4 without success.
• Operating Systems: Tested on Ubuntu and Manjaro. Issues were encountered on MacBooks with Apple Silicon. Windows has not been tested. We recommend using Ubuntu Linux for the PUF steps.
• Proof of Concept: This project is a proof of concept. We do not recommend deploying it on a production network or the mainnet. No liability is assumed for any use of this project.

How to Run

1. Generating an SRAM-PUF

A Physical Unclonable Function (PUF) leverages the intrinsic randomness of the hardware to derive a unique identifier. To generate the PUF, we use the randomness of the SRAM at startup. This requires overwriting the original bootloader, as it initializes the SRAM, preventing access to the startup SRAM data.

Using an Arduino Board as an ISP

To load a custom bootloader, one Arduino board will act as an ISP (In-System Programmer) to program another board (the "target" board).

1. Set up the Programmer Board:

   • Connect one Arduino board to the PC.
   • Open the Arduino IDE.
   • Go to File -> Examples -> 11. ArduinoISP and load the ArduinoISP sketch onto the board.
   • Go to Tools -> Programmer and select Arduino as ISP.

2. Connect the Programmer and Target Boards:

   • Use the following pin connections:

     Programmer Pins	Target Pins
     PIN 10	RESET
     PIN 11	PIN 11
     PIN 12	PIN 12
     PIN 13	PIN 13
     5V	5V
     GND	GND

Compiling and Loading the Custom Bootloader

1. Download the content of the Arduino PUF folder.
2. Connect the Programmer board to the Target board using the above table.
3. Connect the Programmer board to the PC.
4. Navigate to the scripts folder and compile the bootloader using:

   ./compile_bootloader.sh

   The compiled bootloader will be available in the build folder.
5. Flash the bootloader using:

   ./flash_bootloader.sh <path to bootloader.hex>

   Make sure to use the correct file.

Obtaining Two Unstable PUFs

1. Disconnect the Target board from the Programmer board.
2. Disconnect the Programmer board from the PC.
3. Connect only the Target board to the PC.
4. Check the serial port using:

   ls /dev/tty:.*

   Note the port name (e.g., /dev/ttyUSB0 or /dev/ttyACM0).
5. Open two terminals and run minicom on both: On the first terminal:

   minicom -D /dev/tty.usb_portname -b 115200 -C file1.txt

   On the second terminal:

   minicom -D /dev/tty.usb_portname -b 115200 -C file2.txt

   Make sure to disconnect and reconnect the Target board between minicom executions.
6. Extract the unstable PUFs from the two files and save them as enrollement/dump/new_arduino_1_0.puf and enrollement/dump/new_arduino_1_1.puf.

Obtaining a Stable PUF

1. Run the enroller script:

   ./enroller > helperdata.txt

2. Extract the helper_data field from helperdata.txt. Convert it by adding 0x before each byte and separating them with commas (e.g., 466f727a61204e61706f6c69 becomes 0x46, 0x6f, 0x72, 0x7a, 0x61, 0x20, 0x4e, 0x61, 0x70, 0x6f, 0x6c, 0x69).
3. Open the bootloader/puf.c file and insert the converted helper data:

   const uint8_t helper_data[304] PROGMEM = {/*insert here the converted helper data*/};

4. Compile the modified bootloader and burn it on the Target board.
5. Extract the stable PUF:
   • Connect the Target board to the PC.
   • Run minicom:

     minicom -D /dev/tty.usb_portname -b 115200 -C puf_response.txt

   • Type x in the minicom terminal to print the stable PUF.
   • The stable PUF will be saved in puf_response.txt.

Now the stable PUF can be used as desired.

2. Deploying the NFT on Hardhat Testnet

1. Initialize a Hardhat Project:

   • Create a new directory and initialize an npm project:

     npm init

   • Install Hardhat:

     npm install --save-dev hardhat

   • Install dependencies:

     npm install @openzeppelin/contracts

   • Initialize a Hardhat project:

     npx hardhat init

     Choose the JavaScript project.

2. Set Up the Smart Contract:

   • Delete the sample contract and deployment scripts.
   • Download the Smart Contract and place it in the contracts folder.
   • Download the deployment script and place it in ignition/modules/.

3. Compile and Deploy:

   • Compile the contract:

     npx hardhat compile

   • Run the Hardhat testnet:

     npx hardhat node

   • Deploy the contract:

     npx hardhat ignition deploy ignition/modules/ArduinoNFT.js --network localhost

The contract is now deployed, and you can interact with it.

3. Interacting with the NFT

Make sure MetaMask is installed, the Hardhat node is running and the Smart Contract is deployed.

1. Set up the DApp:

   • Install Web3.js:

     npm install web3

   • Make sure to insert the Smart Contract address into the const contractAddress variable of the index.html file.

2. Run the DApp:

   • To run the DApp, go to the root of the project and start a webserver:

     npx watch-http-server DApp/

Now you can interact with the DApp to mint NFTs. Make sure to connect MetaMask to the desired network, and notice only the contract owner can mint NFTs (if you're deploying using this guide, the owner will be the Account 0 of Hardhat).

Authors

This project was developed by:

• Simone D'Angelo
• Mariano Aponte
• Sergio Aprea

Acknowledgments

We extend our gratitude to Dr. Franco Cirillo for providing the hardware and software needed to implement the Arduino SRAM-PUF.