iPhone / iPad user profile tracking

My iphone app downloads user specific data from our web server. How can I identify a unique user/device? cookie? ip address? or do I need them to re开发者_如何转开发gister first?

What are some issues I need to be aware of? best practices?

You can get the devices UUID by calling

[[UIDevice currentDevice] uniqueIdentifier]

You probably should register the user when the app is launched for the first time. There shouldn't be any issues that people haven't already found answers to and that you can find by searching SO or google.

Can generate your own UUID's using CFUUID