Like I dunno a physical mechanism that relies on nuclear decay to decide what number to hit. They aren't that complicated, they aren't any more dangerous than a smoke detector and unless you can hack physics (at which point you probably no longer care about money) you can't really mess with them.
In any case this just goes to show the old adage holds true, your system is only secure as its weakest component. Also something about all security measures pretty much flying out the window the second someone has physical access to your hardware etc etc.
I would not have to hack the physics, I would hack the detector.