public function getShortName()
{
$sid = $this->toString();
$rid = preg_match('/^S-1-5-21(-\\d+){2,}/', $sid) ? (string) array_slice($this->subAuthorities, -1)[0] : null;
$domainSid = "S-1-5-21-{domainsid}-{$rid}";
$shortName = null;
if (in_array($sid, self::SHORT_NAME)) {
$shortName = array_search($sid, self::SHORT_NAME);
} elseif ($rid !== null && in_array($domainSid, self::SHORT_NAME_DOMAIN)) {
$shortName = array_search($domainSid, self::SHORT_NAME_DOMAIN);
} elseif ($rid !== null && in_array($domainSid, self::SHORT_NAME_ROOT_DOMAIN)) {
$shortName = array_search($domainSid, self::SHORT_NAME_ROOT_DOMAIN);
}
return $shortName;
}