Comment by GTP

While I agree that there are quite good reasons why digital computers won over their analog relatives, you're now making me think how we could exploit the analog nature of what you're describing for encryption. I have a gut feeling that there would be a way. Encrypting something is about adding noise to the message anyway, and analog is very good at noise. The issue would be reproducing the exact same noise (or close enough, since in your example we need 0.1 V resolution) on the receiving end. Here, an electronic engineer could help.