> Feel free to point out where you previously discussed receipt freeness.

I'm not going to go around spelunking on my old comments to prove to you that your attacks on me are unfounded. Do your own homework if you care about this for some reason but this is getting extremely aggressive for no reason.

> And if you did, then why didn't you mention it in your comment, which gives the false impression that any verifiable voting system cannot be receipt free?

The point of my comment was to explain that what appears to be a common solution to a problem that we'd use in any kind of electronic system breaks down other stuff in electronic voting. I wasn't about to go 10 rounds of "but you could do X and then be broken by Y". My point isn't that there aren't clever ways to engineer digital systems for electronic voting, is that however you do that you end up with something that can be attacked in horrible ways. See below for an example.

> You're going to have to be more specific about what you mean.

Since you haven't provided a voting system for me to attack I'll try with what I consider to be a very good one:

- You vote by pressing a button or touchscreen at your polling place

- A paper ballot is printed with your vote that you verify and drop into a traditional ballot box to be counted as usual

- A receipt is printed with some code that you can later use to check that your vote was counted in a cryptographically secure way

- Paper ballots are tallied locally as usual, electronic results are sent encrypted to a central server that can be later used for vote count verifications

- The electronic count and the paper count are done in parallel and both published. You expect small differences in the count (mostly from human error in the paper count) but as long as the results match up to a low difference you trust your election.

- There are no flaws in any of the crypto and all the polling officials are honest (this last part is something the paper system does not depend on)

So this seems strictly better than a paper election right? You get the electronic count just as the polls close, the safety that you can later check that your vote was counted electronically, and the double-check of the paper count to fall back on. So here's how I attack it if I'm just a skilled hacker working alone:

- Work as a tech at one of the polling places and intentionally miscalibrate touchscreens. People will register wrong results and get some stories out that strange things happened in some polling places.

- Pick polling places where a minority is heavily represented and break those machines in particular. At worst some extra coverage, at "best" the election gets skewed because those polling places start having long lines and people walk away.

- Spread some malicious code to the general population through any of the normal means (Android apps, unpatched vulnerabilities, etc). I just need to get a small number of common citizens. Have that code intercept the place where you check if your vote was counted and tell you it was not. Hopefully you'll recheck in a clean machine and be satisfied. If possible target politicians and the actual losing candidates in the election so that they are particularly worried that the election was stolen from them.

- Finally hack into the central server where you do the checks to see if your vote was counted and make checks fail randomly.

At the end of this you have seeded pretty deep distrust over the election. Depending on how skilled the hacking is it may be enough to break down the trust in your democracy. I'm not willing to take that risk. But now if you're a very well funded hacker group or a state actor you can do more:

- Hack the network providers and selectively DoS the verification server for minorities or parts of the country that voted against the winner.

- Infiltrate the supply chain of a few of the thousands of suppliers of the voting machines and plant hardware level bugs that are time coded or just cause random errors (e.g., the touchscreen bugs)

- Hack the networks used to communicate votes from polling places and DoS those so that the count is delayed

- If you can hack the power grid have power cuts in polling places. If you were voting on paper it wouldn't matter but now you can't vote

- Do all those again in targeted polling places looking for minorities and/or populations that are very skewed from the national average to entice maximum distrust

- After enough doubt is created manipulate social networks based on those cases to nudge the population into thinking the election is rigged. It only takes a small percentage of the population believing that before you have a crisis on your hands (think yellow vests in Paris).

At the end there's a very high chance your election is now fully distrusted and the country is in chaos. Even if it doesn't work 100% of the time it only takes one or two successful events globally for people to distrust these systems, whichever they are.

The scary thing about what I just described is that plenty of it is indistinguishable from what is already happening in some cases in US elections today. I'm willing to hope that the US case is just pure incompetence, but the attack surface is very large and we've seen that foreign state actors are extremely motivated to meddle with elections. I expect more examples of this in the future, particularly since the actual systems deployed are incredibly poor compared to this one.

> This is called receipt freeness, which we just discussed.
> This is called universal verifiability, which is also perfectly attainable by e-voting systems.

Yep both of these are possible as long as the crypto is sound. No current electronic voting system actually clears that bar, most have no crypto at all. But there's no reason you couldn't do it at enormous extra cost if you had enough extremely competent people dedicated to the problem. I still haven't seen a good argument why you'd want to though. Which is the second part of this problem. If there are no advantages why do it? Proper paper counts are cheap, well tested and get results 2 or 3 hours after the polls close. The US is notorious for not being able to do that but it's routinely done across the world with no issues.

> You've provided no reason whatsoever to believe that citizens will never trust e-voting systems, and there is strong evidence against this from the fact that they are perfectly willing to engage in e-commerce and e-banking.

See the above attack scenarios for why I definitely think citizens should never trust any electronic voting system. The difference for eCommerce and eBanking is that under any of those attack scenarios you just go to the bank branch and sort things out, including reverting transactions. You can't do that with your vote. Once the verification system fails the whole election fails and the faith in your democracy plummets. None of those attacks are specific to this system either. They're just relying on the flexibility of computers versus the extreme lack of features of pen and paper.

> This is just flat-out wrong and reflects your ignorance of the subject. It is perfectly possible to have all of the above properties simultaneously.

At this point it's on you. Feel free to improve on the above system to try to get the three properties. It's extremely unlikely you'll be able to just from the nature of computers and computer networks. We put up with all their extra complexity for all the extra value they bring. I couldn't be having this discussion with a person I don't know that is most likely half way across the world without the internet. But all that complexity plays against you when you're trying to secure a vote. You don't need to change the vote to destroy an election. You just have to seed enough distrust that the process is no longer accepted.

The most important characteristic of the voting process is that you are able to convince those who lost that they've really lost and what computers/networks have in abundance is failure modes and corner cases. Couple that with the lack of knowledge of the general population (and certainly of most politicians) about technology and it's very easy to attack an election by just engineering doubt over the whole system even if all the failures that you induce were designed for.