218     function mod($base, $modulus)  argument
220         return bcmod($base, $modulus);
238     function _powmod($base, $exponent, $modulus)  argument
240         $square = $this->mod($base, $modulus);
244                 $result = $this->mod($this->mul($result, $square), $modulus);
246             $square = $this->mod($this->mul($square, $square), $modulus);
252     function powmod($base, $exponent, $modulus)  argument
255             return bcpowmod($base, $exponent, $modulus);
257             return $this->_powmod($base, $exponent, $modulus);
304     function mod($base, $modulus)  argument
306         return gmp_mod($base, $modulus);
319     function powmod($base, $exponent, $modulus)  argument
321         return gmp_powm($base, $exponent, $modulus);