I would like to discuss which are all the possibilities for a browser game to detect whether a registered user has multiple accounts.
With "multiple accounts" is named the practice of one single player having more than just one profile in the game.
However, this limits the possibilities of interaction in the game between family members (and in general, everyone sharing same computer and/or connection), even if they are actually different persons.
My question is exactly which ways can be used to identify multiple accounts?
I already know from some previous research that they can use the IP address. Is it enough in this case to use a VPN caring about WebRTC leak? Or running a game (using FlashPlayer or other programs) opens other possibilities to get the real IP?
I am also aware about cookies. In this case is it enough to use CCleaner, different browsers for each account and surfing under "private mode"?
What about MAC addresses? Which one can they get? Of which of them have I to take care of? Just the ones related to my hardware or also the router one (or other like that)?
Is there any other point I am missing?