An apparatus includes a first sequential circuit which captures an input signal according to a first clock signal, a second sequential circuit which captures the input signal according to a second clock signal and outputs the captured input signal to a logic circuit, the second clock signal being modulated so that a period of the second clock signal is shorter than that of the first clock signal, a third sequential circuit which captures an output signal of the logic circuit according to the second clock signal, and a verification circuit which verifies whether an output signal of the first sequential circuit and an output signal of the third sequential circuit match with each other.