> and likely will ever be able to do this well given that someone can always recompile a malicious OS that pretends to be another well-trusted OS I don't under

> and likely will ever be able to do this well given that someone can always recompile a malicious OS that pretends to be another well-trusted OS I don't understand your concern here. Do you mean an evil-maid style attack? At some point you need to trust the user to keep their device secure. A Windows can also have malware.