Using Firebase Authentication with Unity on standalone game

问题

I want to make a cross platform game using Firebase with Firebase Unity SDK(now Version 1.1.1).
I would like to use Firebase realtime database.
I know that SDK does not correspond to standalone game and on UnityEditor, but it works without problems on standalone game limited realtime database. However, Authentication can not be used in same situation so it is necessary to open permission rules:

  "rules": {
    ".read": true,
    ".write": true
  }

But it is never realistic to use actually.

Do you have good ideas to use Firebase Authentication with Unity3D on standalone game?
Or does that SDK have been planned to correspond to standalone game?
Firebase is very powerful, but I regret that it can not unify all the circumstances.

来源：https://stackoverflow.com/questions/41788413/using-firebase-authentication-with-unity-on-standalone-game