You cannot solve it with cryptography. I understand cryptography but my parents don’t, so I will be voting instead of my parents. This way, I get three votes while they get zero votes each.[0]

I'll quote Bruce Schneier [1]:

   If you think cryptography can solve your problem, *you don’t understand your problem* and you don’t understand cryptography.

0: I already do anything related to any interaction with a computer system for them (including payments, social security, medical, travel, etc.)

1: He dug into the origins of this here: https://www.schneier.com/blog/archives/2026/05/laurie-anders...