iPhone Applications & Privacy Issues: An Analysis of Application Transmission of iPhone Unique Device Identifiers (UDIDs)
by Eric Smith October 1, 2010
Every Apple iPhone shipped since its introduction in 2007 contains a unique, software-visible serial number -- the Unique Device Identifier, or UDID. Apple provided this functionaly to allow application developers to uniquely identify the iPhone being used for purposes such as storing application preferences or video game high scores. While the UDID does facilitate the process of collecting and storing certain types of data, it also creates a tempting opportunity for use as a tracking agent or to correlate with other personally-identifiable information in unintended ways. In this paper, we investigate where and how UDIDs are being shared, with whom, and how the UDIDs are being used.