I'm working on the server side part of my game (develop your village/farm) and trying to build user identification system. I'd like to have a password-less mechanism: user downloads my app from the store, run it and that's all. He doesn't have to type any login or password. The game connects with the server requesting new player creation so he can start playing as soon as he opens the app.
I assume that this process is connected with GameCenter/GooglePlayGames. A game retrieves player ID from those services and then use it for future requests (saving user progress, game specific data - like village/farm facilities' positions, other information on my server). Is it a valid and safe assumption? If not can ask you to describe how it works/should be done?
I have some doubts regarding security? Single PlayerID seems to be quite weak solution, isn't it?
I didn't mention it but I would like to move my progress from one device to another also without creation of any account with login and password.