Also note that I specified I'm more concerned with verification of trusted hardware on my own device. Because the repercussions of malicious hardware implanted in my own device cannot be mitigated purely in software. Whereas verifying the integrity of an external device inherently depends solely on software, since there is no hardware interaction. I'm still concerned about it, in the sense that I'd like my OS to take best efforts to only "trust" external devices insofar as it can verify they're trustable, but I also accept that those devices are outside of my control and so any protocol for trusting them will have holes in it. My main requirement is that I should be able to opt out of the system if possible (by e.g. disabling bluetooth).