OEM lock in previous versions used to provide some amount of obscurity but it’s no longer available in 8.0+.
We don’t really have a replacement in the works right now.
The truth is there is no way to actually secure your resources. If Ignition can read them, which it must be able to in order to function, then so can any moderately determined or intelligent adversary who has access to your gateway (local filesystem access, not necessarily remote, though it can also be achieved by someone with Designer access). There is simply no way real, secure, way around that. There are options that would obscure or make it more difficult but nothing more.