You can't buy votes on paper because you need to be alone in the voting booth. You could disable people to vote, but not force them to vote as you want. As for

You can't buy votes on paper because you need to be alone in the voting booth. You could disable people to vote, but not force them to vote as you want. As for the value of digital signature, I don't think it's legally equivalent to the physical signature, at least in my country. I've yet to see any administration accepting a digital signature.