How to identify a user through devices on iOS?

Question

I am working on an application in which the user will buy some “credits” as purchases in the application and use them to purchase some services inside the application. Since a user can have more than one device, I need to identify it on different devices.

I understand that I can create several logs (and store user accounts on my own server), but I would like to avoid this. At best, I would like to use an Apple ID, but I can’t understand how I can access the Apple ID inside the application?

Here I found similar questions, but did not answer them. I do not believe that there is no way to access the Apple ID from the application (I do not need a password, just an identifier), since I found something like AVMetadataiTunesMetadataKeyAppleID in AVFoundation, but this structure seems to be designed only for Mac OS X.

Any suggestion how to solve this?

Answer 1

Unfortunately. There is no way to do this without using your own authentication system on your own server. UDIDs are unique to each device, and Apple does not provide access to the iTunes user account at all.

Answer 2

Another way is you can use facebook authentication for this. Just connect the application using facebook api and you can save your login with additional information.

It may also be useful for your application if they can share their application with their friends on facebook: p

Answer 3

You can identify the user using GameKit.