Check out Google Votes (pdf) in the end they wound up sacrificing pure anonymous votes for the (IMO) more important factor of accountability in delegated votes. You could have a separation of votes delegated to you and your personal vote so that you couldn’t learn the votes of people by just delegating votes to them as a monitor.
There’s a lot that’s easier in paper voting that gets massively complex when we try to do it securely digitally simply because physical security of a voting place and a voting box is much simpler to track and verify.
