A microcontroller (MCU) generally has an internal program flash area and a data eeprom area (or one) for users to store programs and working data (or one).

In order to prevent unauthorized access or copying of the internal program of the secured microcontroller, most of the microcontrollers are equipped with an encryption lock bit or encrypted byte to protect the on-chip program.

If the encryption lock bit is enabled (locked) during programming, the program in the locked microprocessor cannot be directly read by an ordinary programmer, which is called single-chip encryption. (BugPS: MCU programs basically exist in Flash, and most of them can read or recognize the data on Flash to obtain Firmware files, which brings opportunities to copy products).

With the help of special equipment or self-made equipment, a single-chip computer attacker can use a variety of technical methods to Reverse Engineering Microcontroller and then extract key information from the chip and obtain the program inside the single-chip microcomputer. This is called decryption of the single-chip microcomputer flash memory.