This may come as a surprise to you... but if you can put the number into a webpage... so can that person in authority. Whether it's a receipt you keep with the vote readable, or a number you put into a webpage.
Any time that you can verify after you leave the polling place which way your vote was recorded ... so can someone else. And that can lead to very serious consequences. Loss of job, family, the stakes are endless.
All that is required for you to verify your vote is a human-readable paper record that will be kept separate from the electronic record, but doesn't leave the polling place. That way you can verify it after you vote electronically, and if a recount is done, the paper trail box can be unlocked and counted.