A basic requirement is that the result reflects the intent of the voter. That is to say, the vote cast should not change between the moment it is cast, and the moment it is counted. From it leaves the control of the voter, to it arrives to the persons checking the result, it should remain constant. This rather self-evident requirement is apparently too self-evident to be considered in most analyses I have read. What happens if we apply it to electronic voting?
Let’s start with ceramic chips, bone fragments, twigs, and regular paper ballots with the name written on it. You write the candidate’s name (or whatever the election is for) on a physical object, and put it in the recipient of the votes, which is constructed so that nobody can remove or add votes without being detected. Due to the Laws of Nature, the physical object containing the vote will remain the same until the moment it is counted. Not so with electronic voting, however.
Electronic votes are stored in computer memory. These are read/write devices, i.e., they can be changed. A bit can be set or reset without anybody noticing. The vote is not stored as a physical object, but as the state of some atom or molecule, or group thereof. It is a fundamental difference which ought to disqualify all those machines.
Is there a way to create a reliable electronic voting system? Maybe. First off we need to use a storage device that cannot be altered. We need a PROM, a programmable read only memory. Assume that we have a memory that starts from only zeroes, and that can be changed to 1 but never back to 0. We then assign a block of memory for each candidate, and add a logical “1” for each vote cast for each candidate. A vote cast can never be subtracted. If someone adds votes in an attempt at fraud, the total votes will not match the number of voters on the voting roll. To sum up the machine would just need to sum up the number of 1’s for each candidate. By standardizing the addresses where the votes are stored, a PROM chip could be inserted in any machine for independent verification. The PROM could either be stored and replaced in the next election, or one could use an erasable kind of PROM, specifically a UVPROM which requires long exposure to strong UV light to reset. The other kind, EEPROM, can be reset invisibly with electricity, and that is not what we want. Personally I’d prefer the PROM that cannot be reset, and that they be stored as part of the national archives after the election. To implement this kind of electronic voting basically requires standardizing the format in which data is stored on the PROM. All other hardware would preferably be open-source and ideally NOT contain any programmable device, only electric hardware.
This machine would behave like having separate ballots for each race, and it would be impossible to see how individual voters voted in different elections. This is a democratic advantage compared to having a single ballot for all race.