To enable SteamAuth, add the following to "DefaultEngine.ini", or to the platform-specific engine .ini file (such as "WindowsEngine.ini", "LinuxEngine.ini", or "MacEngine.ini") for each platform that is intended to support Steam Online Authentication:
Once enabled, the Steam Online Subsystem interface (SteamOSS) function,
GetAuthInterface, can be used to access SteamAuth functionality.
Enabling SteamAuth will cause the application to run authentication procedures (against the Steam service) for all joining players. By default, SteamAuth will kick players who fail this check will be kicked, but this behavior can be overridden.