[DBrow]

Well, that is strictly true.

But you can design a system that makes changes apparent.

I work with an engineering documentation setup that is pretty unhackable. I can make a change, but no way can I hide the change or who did it.

Possibly I could hide who made the change, but the change itself is not hideable.

[supercat]

But you can design a system that makes changes apparent.

It's possible to design electronic systems to make votes immutable, by having representatives of each party give each other digitally-signed copies of them immediately at close of polls. I am unaware of any system that does that.

[weegee]

If you do an image compare of the firmware on the ballot box after the election to what was shipped from the factory, any changes would be apparent. The nature of those changes wouldn’t be known per se, but the images would not be the same (the bits would stick out).