private function cipher()
{
switch ($this->header['enc']) {
case 'A128GCM':
case 'A256GCM':
throw new JOSE_Exception_UnexpectedAlgorithm('Algorithm not supported');
case 'A128CBC-HS256':
case 'A256CBC-HS512':
$cipher = new Crypt_AES(CRYPT_AES_MODE_CBC);
break;
default:
throw new JOSE_Exception_UnexpectedAlgorithm('Unknown algorithm');
}
switch ($this->header['enc']) {
case 'A128GCM':
case 'A128CBC-HS256':
$cipher->setBlockLength(128);
break;
case 'A256GCM':
case 'A256CBC-HS512':
$cipher->setBlockLength(256);
break;
default:
throw new JOSE_Exception_UnexpectedAlgorithm('Unknown algorithm');
}
return $cipher;
}
