updated 04:54 pm EDT, Wed July 18, 2012
Apple has begun attaching unique identifiers to the validation receipts for in-app purchases, according to MacRumors. The change is believed to be an escalation in Apple's attempts to defeat a hack allowing free in-app purchases. The Russian coder responsible for the hack has managed to circumvent past Apple measures.
The new identifier is believed to include the UDIDs of devices making purchases. One developer suggests that this could pose a problem for Apple, since the company is supposed to be rejecting apps which use UDIDs in order to cope with privacy concerns. A UDID is tied to a specific device, and by extension it could potentially be used to identify an individual and their activity.