There was a great write up by someone about designing a Trusted computing type of authentication device and how it should operate. I believe the requirements we

There was a great write up by someone about designing a Trusted computing type of authentication device and how it should operate. I believe the requirements were write-only flash for the program code and an interface to reflash it. That way you can create whatever program you want and embed whatever secrets you want in it yourself and if you lose it, nobody should be able to retrieve them. I think that would be a use case of hardened hardware. Same with a lost cell phone type of thing.