iOS 5 - No more UDID - How to keep some critical datas to identifiy the user even if app is deleted

I've just read on a blog that the UDID will not survive iOS 5. I us开发者_开发知识库e it as an identifier combined to an app ID I generate myself. Without that UDID, I will just have the App Identifier but as it is stored in the userDefaukts for the moment, it is deleted if the app is uninstalled.

How may I do to keep it safe even if the app is deleted from the iPhone ? I have to achieve this to ensure that I have at least one stable identifier, even if it's not the sole one I use to identify the user.

Check this out, its designed specifically for this problem: https://github.com/gekitz/UIDevice-with-UniqueIdentifier-for-iOS-5