private function _checkEntityAlternativeNames(GeneralNames $san): bool
    {
        // only directory names supported for now
        $name = $this->_entityName->firstDN();
        foreach ($san->allOf(GeneralName::TAG_DIRECTORY_NAME) as $dn) {
            if ($dn instanceof DirectoryName && $dn->dn()->equals($name)) {
                return true;
            }
        }
        return false;
    }