I'm wondering about using human input as an entropy generator. We all know humans are terrible at making up random numbers or keys or passwords. But what if we let a user 'randomly' type in some garbage. Just smashing the keyboard, so to speak.
How much randomness does that give, or rather, how much bits of entropy would it generate?
Obviously, way less than 2log(number of keys on keyboard), but I'd say 'a few' bits per keystroke feels about right? After one keypress, the next will be either a key close by (with another finger of the same hand) or one on the opposite side of the keyboard (with the other hand). So I would roughly guesstimate that at somewhere between 2 and 3 bits per stroke.