Firmware-Protection with MAC-Based Registration

This project provides a simple registration mechanism for ESP32/BW16 devices using the device's MAC address and MD5 hashing. It prevents unauthorized use by verifying a unique hash on boot. If the hash does not match, the user is prompted to enter a registration code via Serial Monitor.

This code will protect your firmware from cloning.

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🧰 How to Use the Code

To use the protection system in your own firmware:

1. Include the Header

#include "protect.h"

2. Call ProtectSetup() in setup()

void setup() {
  ProtectSetup();       // Will prompt for registration if device is unregistered
  Serial.begin(115200); // Optional: for serial debug output
}

void loop() {
  // Your application code here
}

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🔐 How It Works

1. MAC Address Retrieval:

   • The device reads its own MAC address.
   • Example: A1B2C3D4E5F6

2. Hash Generation:

   • The MAC address is salted with a secret string: SALTYFISH.
   • It is then hashed twice using MD5:

     doubleMD5("SALTYFISH" + macAddress)
     

3. Registration Flow:

   • On first boot or unregistered device:
     • User sees a message on Serial Monitor asking for a registration code.
     • If the entered hash matches the expected one, it is saved to EEPROM.
     • On next boot, the device checks EEPROM and allows usage if the hash is valid.

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🧪 How to Register a Device

1. Generate Registration Code (off-device):

Use this Python code:

import hashlib

def double_md5(data):
    first = hashlib.md5(data.encode()).hexdigest()
    second = hashlib.md5(first.encode()).hexdigest()
    return second.upper()

salt = "SALTYFISH"
mac = "A1B2C3D4E5F6"  # Replace with the actual MAC address
reg_code = double_md5(salt + mac)
print("Registration Code:", reg_code)

2. Upload the firmware to the ESP device.
3. Open Serial Monitor.
4. When prompted, enter the registration code from step 1.
5. If valid, the device stores it and restarts. On the next boot, it runs normally.

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📁 File Breakdown

protect.h

Function	Description
getMACAddress()	Returns MAC address as uppercase hex string without :.
doubleMD5(data)	Performs MD5 hashing twice on input data.
writeHashToEEPROM()	Saves valid hash to EEPROM.
readHashFromEEPROM()	Reads hash from EEPROM for comparison.
promptForHash()	Prompts user via Serial to enter registration code.
ProtectSetup()	Main setup call to validate or prompt for registration.

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🧠 Notes

• You must ensure the EEPROM.begin() size matches your device limits.
• This system assumes physical access (via Serial) is required for registration.
• You may change the SALT constant to something unique to your application.

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📜 License

This project is provided under the MIT License. Modify and use freely.

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