Right, I somehow managed to fail to link "signature" with "identifies whose vote it is". So we seperate signing off on voting and the actual vote (both in the machine and on the receipts) we'd be good. Perhaps a pre-voting machine that gives you a "voting pass" when you log-in and sign electronically, which you put in the voting machine to activate it (and don't get it back)? (I'm trying to seperate the "signing in to the vote" process from the voting itself, to maintain privacy.)