I sort of like the commenter who says voting machines ought to meet the standards set up for gaming machines in Nevada, but ultimately, I fall on the side of the paper-and-pencil crowd:
You can't trust what you don't understand, so any voting system needs to be Universally Comprehensible. An electronic system based on Open Source principles -- where the blueprints for the hardware and the listings of the software are available for all to examine -- is still really only comprehensible to a minority of the population. It doesn't satisfy the goal. (In the worst case, you could conceal a deliberate design defect by a combination of hardware and software techniques: anybody examining the hardware and not the software, or vice versa, will miss it.)Tomorrow is "Super Tuesday," which means lots of voting around the U.S. (including here in my neighborhood). I hope it goes well.
Just forget the whole thing as a failed experiment, and go back to pencil and paper and manual counting. Everybody knows what all the possible failure modes are, and how to minimise their effects.