public function toPEM()
{
$keys = $this->getKeys();
$result = [];
foreach ($keys as $key) {
if (!in_array($key->get('kty'), ['RSA', 'EC'])) {
continue;
}
$pem = $this->getPEM($key);
if ($key->has('kid')) {
$result[$key->get('kid')] = $pem;
} else {
$result[] = $pem;
}
}
return $result;
}