A method of making a secure integrated-circuit system comprises providing a first integrated circuit in a first die having a first die size and providing a second integrated circuit in a second die. The second die size is smaller than the first die size. The second die is transfer printed onto the first die and connected to the first integrated circuit, forming a compound die. The compound die is packaged. The second integrated circuit is operable to monitor the operation of the first integrated circuit and provides a monitor signal responsive to the operation of the first integrated circuit. The first integrated circuit can be constructed in an insecure facility and the second integrated circuit can be constructed in a secure facility.