protected function passFromSession($macHash, $hash, $time)
    {
        $pass = null;
        $session = $this->getSession();

        if (($hashArray = $session->getVariable('captchaHashes'))) {
            $pass = (isset($hashArray[$macHash][$hash]) && $hashArray[$macHash][$hash] >= $time) ? true : false;
            unset($hashArray[$macHash]);
            if (!empty($hashArray)) {
                $session->setVariable('captchaHashes', $hashArray);
            } else {
                $session->deleteVariable('captchaHashes');
            }
        }

        return $pass;
    }