If your smartphone is an Apple iPhone
On Apple iPhone, the IBKR Mobile Authentication (IB Key) relies on the security element already used by the iOS. The IBKR Mobile Authentication (IB Key) can utilize either Face ID or Touch ID or the phone Passcode.
In order to activate and use the IBKR Mobile Authentication (IB Key), your iPhone has to be at least secured with a Passcode. Should you need additional information, you can consult the Interactive Brokers Knowledge Base.
If your smartphone is an Android
In case you do not use any security element to protect your smartphone access, the IBKR Mobile Authentication (IB Key) will rely on an independent PIN code, elected by you during the app activation. Hence the IBKR Mobile Authentication (IB Key) does not require your Android smartphone to be secured by a Passcode.