A microcontroller comprising a first integrated circuit configured to receive power from a power supply comprising a second integrated circuit via at least one power input terminal and wherein at least one communication terminal provides for communication between the microcontroller and the power supply, wherein the microcontroller is configured to provide for encrypted communication between the power supply and the microcontroller based on a pre-shared encryption key, the encrypted communication configured to provide for authentication of the identity of the power supply and, if the power supply passes the authentication, the microcontroller is configured to operate in a normal mode and receive said power from the power supply, and if the power supply fails authentication, the microcontroller is configured to enter a tamper mode.