Hardware TRNG "Kluchnik" — ESP32 Firmware

This is the firmware repository for the "Kluchnik" hardware True Random Number Generator (TRNG). The firmware is written in C++ using the Arduino framework and is designed for the ESP32 Dev Kit C board.

⚙️ How it Works

The device generates true random numbers by using two sources of physical entropy:

• Chaotic Motion: A 6-axis MPU-6050 sensor reads acceleration and rotation data that occurs when the user shakes the device. This data is unpredictable and serves as the basis for randomness generation.
• Generator Jitter: An external high-frequency oscillator (~100 kHz) creates a stream of pulses.

The ESP32 firmware uses the data from the MPU-6050 to open a digital "gate" for random intervals of time, allowing a random number of pulses to pass through to an 8-bit hardware counter. The final value on the counter is a single, truly random byte.

The generated 128-bit key is encrypted on the device using AES-128-CBC (mbedtls) and is transmitted over Wi-Fi to the desktop application.

✨ Features

• True Randomness: Gathers entropy from two physical sources (chaotic motion and oscillator jitter).

• Secure On-Device Encryption: Encrypts the generated 128-bit key using the robust AES-128-CBC standard via the mbedtls library.

• Wi-Fi Access Point: Creates a local Wi-Fi network for the client application to connect to.

• TCP Server: Transmits the encrypted key and user settings securely over a TCP socket.

• Onboard Interface: Allows for full configuration via a 1.3" OLED display and three push-buttons.

• Remote Controllable: The device's menu can be fully controlled by the desktop client application.

🔌 Hardware Components

To build the device, you will need:

• ESP32 Dev Kit C board
• MPU-6050 sensor (accelerometer + gyroscope)
• 1.3" I2C OLED display (128x64, SH1106 driver)
• 3x tactile push-buttons
• External Circuitry:
  • Clock pulse generator (~100 kHz)
  • Digital gate (e.g., a 74HC08 AND logic gate)
  • 8-bit counter (e.g., 74HC590)

Pinout (ESP32 Pins)

Component	ESP32 Pin
I2C (OLED, MPU)
SDA	GPIO 21
SCL	GPIO 22
Buttons
Up	GPIO 13
Down	GPIO 12
Select	GPIO 14
TRNG Circuit
Gate Control	GPIO 27
Counter Reset	GPIO 26
Read D0-D7	GPIO 4, 5, 15, 16, 17, 18, 19, 23

🛠️ Build and Flash

1. Development Environment

It is recommended to use PlatformIO with Visual Studio Code for convenient library management and building. The Arduino IDE can also be used.

2. Library Installation

Ensure you have the following libraries installed:

• Adafruit GFX Library
• Adafruit BusIO
• Adafruit SH110X
• Adafruit MPU6050
• I2Cdev

The mbedtls library is already included in the ESP32 toolchain for Arduino.

3. Wi-Fi Configuration

Before flashing, you can change the name and password of the Wi-Fi access point that the device creates. Open the main .ino file and modify these lines:const char* ap_ssid = "Kluchnik"; const char* ap_password = "password";

4. Flashing

1. Connect the ESP32 to your computer.
2. Select the correct COM port in your development environment.
3. Click "Upload".

After a successful flash, the device will create a Wi-Fi access point with the specified name. The OLED display will show the device's IP address (usually 192.168.4.1).