I know that in iOS 7, the app's receipt and the In-App Purchase receipts are combined into an encrypted format with a structure shown here, automatically written to storage.
I know receipt(s) have fields, as documented here.
I know how to retrieve the receipt combo by calling appStoreReceiptURL
.
I know how to validate that receipt by passing it to Apple servers either directly or via my own server.
But how do I parse the receipt to extract its fields?
I need some kind of identifier for each of the possible In-App Purchases so as to record the user's ownership in a way that I can verify repeatedly later.