Identification of a network iOS application by apple ID?

Question

iOS

It is necessary to bind all applications purchased with the same apple ID on any apple device to the same account on the server. When the application is installed and launched, it downloads all of that user's data from the server. If necessary, a new account is created.
All devices and applications of the same apple ID must have the same user. All information about this user comes to applications synchronously, in the form of push notifications.
You cannot bind to an apple ID or its hash (as far as I know, it cannot be obtained). Forced registration and authentication through different sources, such as login / password, facebook, twitter, etc. does not fit. No questions or suggestions for registration should be asked to the user.
What to do? Is this possible, or is the requirement not feasible? What about security?

Answer 1

Can GUID in icloud put?

Answer 2

[UIDevice identifierForVendor]

It seems to be just what you need.

Answer 3

openUDID+MAC+IMEI. Not sure about MAC - maybe already deprecated.