I built exactly what you’ve described, using semi-homomorphic encryption (addition of integers, used plainly as we were under the noise threshold of participants). Luckily for me though, I got to punt on some of the really hard questions of trust — the nodes that were communicating are adversarial, but the outside “organising” network was the government and “us” (company I worked for). It’s a really fun problem. I highly recommend taking a crack at it, or even just reading the literature regarding digital voting — you need to prove that one vote was cast for a given person, and no more, without ever tying back any specific vote to said person, and with a huge range of attack vectors!