* <tt>status</tt>: A string, containing one of the values "ok", "pending", "refunded", "expired" or "invalid".
* <tt>reason</tt>: An optional field, normally only populated when a receipt is invalid, this will give you a reason it failed.
Application-level authentication on the verifyURL request is not strictly required, as the possession of a receipt proves that the application is already part of a trusted message flow.