Where to store a piece of important data (away from users) that will be backed up by itunes

Question

I am currently making an app and there is an important piece of information I need to store. The user can make a one time in-app purchase.

My question is, what is the apple recommended or approved method for storing this?

No. 1 is most important to me. For example imagine the user can purchase 10 lives. After his purchase he will use some of them so imagine he now has a balance of 5. Where should this number be stored.

The issues or thoughts or random ideas I have as a result of reading things are;

• if its saved in a simple file then a jailbreaker can just go in an edit the file.
• if its saved in an encrypted file I think I have extra issues with my app/Apple/certain countries because I am using encryption.
• what happens when the user accidentally removes the app. He cannot restore his purchases as its a one time purchase
• should I be and how should this important piece of information be backed up on a sync
• how do I ensure this information is saved as part of a backup.

Answer 1

I am not sure there is one answer to this problem. In my case I save the information in the keychain. Other iOS SDKs such as Amazon's or Facebook's do the same thing as far as I can see.