1. A method for preventing activation of hardware backdoors installed in a digital circuit, the digital circuit comprising one or more hardware units to be protected and a clock which produces a clock signal, the method comprising: initiating a timer set for a period less than or equal to a determined validation time period of the digital circuit; performing a reset operation on the hardware units upon expiration of the timer by turning off power to the hardware units for at least one cycle of the clock signal to interrupt operation of the hardware units; continually repeating the initiating of the timer for further reset operations while the digital circuit is in operation.