Nette\Forms\Controls\CsrfProtection::generateToken PHP Method

    private function generateToken($random = NULL)
    {
        if ($random === NULL) {
            $random = Nette\Utils\Random::generate(10);
        }
        return $random . base64_encode(sha1($this->getToken() . $random, TRUE));
    }

 /**
  * @return bool
  * @internal
  */
 public static function validateCsrf(CsrfProtection $control)
 {
     $value = $control->getValue();
     return $control->generateToken(substr($value, 0, 10)) === $value;
 }