Earlier quoted context omitted.
> Why we can find whole ATMs at junkyards is beyond me: there are many easy to spot flaws. If there are many easy to spot flaws, I don't think finding them in a junkyard is the root of the problem here. This is good old security by obscurity. As Bruce Schneier says (at least about safes), you should be able to publish the blueprints and source code for the machines, then maybe they'll be secure. There should be enoug…
It's a false dichotomy. Your private keys are just "obscure" information that requires some effort to find too. And security protocols can be designed so the keys aren't enough. At the end of the day it's an arms race, and you're just trying to slow attackers down.
Replace 'physical' with 'cryptographic' and 'authority response time' with 'reasonable amount of time'. It's literally the same thing.