... make the submission of a vote IDENTICAL for everyone: means pen and paper. Paper ballots go into a sealed envelope that gets dropped into a sealed and uniquely identified ballot box that is brought to the counting place. The opening of the ballot boxes as well as the counting has to be open to the public, same as it should be to allow the public to observe voting at polling places as long as that does not interfere with the voting process (5 witnesses is OK, 500 probably not). That is the only way for the public to organize voting control by tallying the votes cast and comparing them to the votes counted. It would eliminate stuffing the ballot boxes or exchanging them during transport or having special interests rig the final tallies.
That is almost exactly the way that voting works in the UK. Anyone can go and observe a count, and verify that the seals on the ballot boxes haven't been tampered with before they are opened.