A method and circuits for implementing a temporary disable function at indeterminate times of circuitry to be protected in a semiconductor chip, such as in an integrated circuit or a system on a chip (SOC) by modulating threshold voltage shifts of a timing sensitive circuit, and a design structure on which the subject circuit resides are provided. The timing sensitive circuit is designed to be sensitive to threshold-voltage shifts and is placed over an independently voltage controlled silicon region. Upon startup, the independently voltage controlled silicon region is grounded, and then is left floating. Each time a hack attempt or predefined functional oddity is detected, charge is applied onto the independently voltage controlled silicon region. After a defined charge has accumulated, the device threshold voltages in the timing sensitive circuit above the independently voltage controlled silicon region are modulated causing the timing-sensitive circuit to fail.