Hmmmm, I guess the key is that each group's auditing process itself has to be open and "objective"---paper ballots are pretty easy in this regard, every group l

Hmmmm, I guess the key is that each group's auditing process itself has to be open and "objective"---paper ballots are pretty easy in this regard, every group looking at the same ballot will usually agree who the vote is for. Math/encryption could possibly work too, at least in the sense of being "objective", although it has other legitimacy problems due to being difficult for lay people to understand and trust. As far as I know, controversies over audits or the independent observers themselves being corrupted aren't really a problem in the US at least, so I'm not too worried about this.