Microcontroller Units (MCUs) are generally equipped with internal EEPROM/FLASH for users to store programs and working data. To prevent unauthorized access to or copying of the on-chip programs of the MCU, most MCUs are integrated with an encryption lock bit or encryption byte to protect the on-chip programs. If the encryption lock bit is enabled (locked) during programming, the program inside the MCU cannot be directly read by an ordinary programmer, which is referred to as MCU encryption or chip encryption. MCU attackers use special equipment or self-made devices, leveraging vulnerabilities in the design of the MCU chip or software defects, to extract key information from the chip and obtain the on-chip MCU program through a variety of technical means.