Abstract: A modular exponentiator is adapted to receive a first communicated signal and derive a second signal therefrom by computation of a modular exponentiation of the form be mod n based on the first signal. The modular exponentiator divides the modular exponentiation according to the Chinese remainder theorem into first and second portions respectively having modulus values p and q of approximately half of an original modulus value n of the modular exponentiation. Each portion of the modular exponentiation is factored into respective pluralities of smaller modular exponentiations having precalculated exponent values. The respective pluralities of smaller modular exponentiations are then multiplied together to provide respective intermediate products. The intermediate products are then recombined to yield the modular exponentiation result.