Details on the new tracking tool were first revealed on Friday by The Wall Street Journal. The new tool will protect user privacy better than "existing approaches," the report said, citing people briefed with Apple's plans.
Apple first announced last year that it would deprecate developers' app access to "uniqueIdentifier," the universally unique serial number embedded in each iPhone and iPad sold. The UDID works like a networked computer's MAC address, and is a unique identifier that remains the same regardless of the user or the app currently running.
Many mobile companies rely on the UDID to serve ads and collect location and preference data. But many have expressed concern that the data could be used to identify individual users.
Exactly what Apple's new tracking tool is and how it will work is "unclear," Friday's report said. It cited one person who said the new identifier is expected to rely on a sequence of numbers not tied to a specific device.
Example of an iPad UDID found in the iTunes device summary tab.
News of the new tool comes only days ahead of Apple's annual Worldwide Developers Conference, which kicks off next Monday, June 11. There, Apple will unveil iOS 6, the next major upgrade to its mobile operating system that powers the iPhone and iPad.
The report was also filed only days after the Journal was first to reveal that ad networks have been using new tracking methods to bypass iPhone security measures. Advertisers have been finding workarounds as Apple has attempted to limit user tracking amid privacy concerns that remain under scrutiny from the U.S. government.
The issue of advertisers relying on UDIDs to track individual users was scrutinized earlier this year, when a U.S. Congress subcommittee sent a letter to Apple CEO Tim Cook, seeking information on what the company is doing to protect personal information stored on iOS devices.