4.2 Decryption

Decryption is the method of retrieving the original message or data and typically cannot be performed without knowing the proper key. Keys can be stored in the bootloader of a microcontroller so that the device can receive encrypted data, decrypt it, and reprogram selected parts of the Flash or EEPROM memory. Decryption keys cannot be retrieved from the encrypted data and cannot be read from AVR microcontrollers if lock bits have been programmed accordingly.