[xroche]

> the voting machine is running the exact same source code?

Or the processor is trustworthy ? Many voting machines are using old processors, such as 68000, and it would not be too hard to emulate a a rogue processor that will have a different behavior, whatever the source code is.

You can also change the behavior of the voting machine at a certain time, or in certain conditions (such as detecting a voting session has started)

The problem is not that voting machines are vulnerable to one or two attacks. There are thousands of ways of compromising them.

The only answer to this is that cryptography specialists do not have any answer to a secure electronic voting not involving a physical element (a bulletin, a receipt, etc.). This means that there is no THEORETICAL solution.