DeviceAuthenticationRequest as a Gateway to Full Authentication 

We recommend using DeviceAuthenticationRequest as a gateway to a full Authentication method like username/pass or a Social Authentication. Device authentication is ideal for Guest accounts or on-boarding accounts before moving on to another Authentication method for transferable player accounts.

HTTP Callbacks

Alternatively, it is possible to get information via a HTTP callback to GameSparks. The idea being the Client would fire a HTTP request to a GameSparks callback, with the response containing the information you want.