I want to store a text file about store users preference on iPhone / iPad / iPod.

I am game developer and want to store user prefernce and purhcase history information at some where on Device and would be preserve between application update and remove / reinstall. but as i know Document's folder of apps just preserve it's data during updata, but due to some reasons user will delete the application and reinstall it at that time data will be lost.

So I want some sequre location for device where i can store data and even it's not clash with securiy policy of Apple Sotre

thanks in advance