Earlier threads in this new democracy tag will point you to other articles about your questions. Actually, we can provide voters with receipts in a way that protects secret ballot and stops vote selling -- but the system is difficult for people to understand, so it is unlikely to happen. In fact, you end up publishing all ballots on the web, and voters can check theirs is there, but can't prove it.

Many people are fighting to stop having black box style voting, and we are winning in a number of areas. Having one machine help generate the paper ballots, and another machine optical scan them allows us to not have to worry nearly so much about the security on the first half, and thus is a good idea.