Most of the modern mechatronic system are equipped with a lot of MCUs that exchange a vast amount of sensitive data among themselves through serial connections, all in plain text and without any protection. This makes them vulnerable to malicious actors who could manipulate original devices and transmit unauthorized messages to sabotage the system. Therefore, there is a need to introduce protections in serial communications to avoid the decryption of the messages. To tackle this challenge, I used an STM32F401RE microcontroller as the system to hack and my PC equipped with a COM port connected to a USB-UART adapter as the hacking device.