Why does everyone want to make it complicated? You don't need hardware. You don't need cryptography. You show your ID and you get a password. The password is t

Why does everyone want to make it complicated? You don't need hardware. You don't need cryptography. You show your ID and you get a password. The password is the same for everyone so it can't be correlated with anyone. Will people share the password? Of course, and they would also share the signatures or devices or whatever else, because you can't prevent that while also preserving privacy.