I am reading about "Bingo voting" (Wikipedia, Paper), and I'm not understanding how it is secure against a corrupt election authority.
If the election authority knows all the dummy votes $N_j^i$, can't it just look at any voter's ballot and tell who they voted for (by finding the candidate on the ballot whose vote is not a dummy vote)?
My question: does the election authority have to be trusted in order for people's votes to be secret from the authorities?