protected function checkKey(JWKInterface $key)
{
Assertion::eq($key->get('kty'), 'oct', 'Wrong key type.');
Assertion::true($key->has('k'), 'The key parameter "k" is missing.');
Assertion::eq($this->getKeySize(), mb_strlen(Base64Url::decode($key->get('k')), '8bit'), 'The key size is not valid');
}