Report: iCloud+ Private Relay could spell the end of iOS ad fingerprinting

Apple ID on iPhone
Apple ID on iPhone (Image credit: Joseph Keller/iMore)

What you need to know

  • Apple will ship iCloud+ Private Relay alongside iOS 15 this fall.
  • A new report considers the privacy feature to be the "beginning of the end" for iOS device fingerprinting.

Apple's iOS 15 release, due to arrive this fall, will see the arrival of iCloud+ and its new Private Relay feature. It'll obfuscate a user's IP address to help prevent them from being tracked across the internet and, according to one report, it could spell the end for iOS device fingerprinting.

According to DigiDay, some ad execs believe that Apple isn't enforcing its App Tracking Transparency (ATT) rules as harshly as it could — but that Private Relay could be the ace in the hole.

Private Relay will re-route an iPhone, iPad, and Mac's data through an Apple server and then out via another one that's owned by a trusted third party. Nobody knows who that third party is, and it's the use of separate ingress and egress servers that ensures a user's privacy — web services will have no idea what their actual IP address is. And neither will the trusted third party, either. It's here where it's thought Apple's anti-fingerprinting goal will really kick in.

Private Relay renders a person's IP address useless for fingerprinting because it redirects web traffic through two separate servers. Granted, an IP address is just one of many aspects that make a fingerprint of someone's behavior on a device — but it's an important one.

What's more, DigiDay believes that Private Relay is just the start, with more Apple-led privacy moves to come that could yet further hinder device — and user — identification across the internet. But it isn't perfect.

There are other loopholes in Private Relay that could be exploited. For instance, Private Relay restricts traffic apps send over an insecure web connection (HTTP). So apps that use an IP address for fingerprinting could theoretically work around this by using a secure web connection or some other transport protocol. This may lead to a "cat and mouse game" between Apple, ad tech vendors with fingerprinting solutions, and the apps integrating them, said Aaron McKee, chief technology officer at mobile ad tech vendor Blis.

It's that cat and mouse game that Apple has signed itself up for and, so far at least, it seems to be up for the fight. Who will win, nobody knows — but I know where my money's going. Privacy is one of the best iPhone features around and that's why Apple promotes it so heavily. It has the bit between its teeth and won't be letting go of it any time soon.

Oliver Haslam

Oliver Haslam has written about Apple and the wider technology business for more than a decade with bylines on How-To Geek, PC Mag, iDownloadBlog, and many more. He has also been published in print for Macworld, including cover stories. At iMore, Oliver is involved in daily news coverage and, not being short of opinions, has been known to 'explain' those thoughts in more detail, too.

Having grown up using PCs and spending far too much money on graphics card and flashy RAM, Oliver switched to the Mac with a G5 iMac and hasn't looked back. Since then he's seen the growth of the smartphone world, backed by iPhone, and new product categories come and go. Current expertise includes iOS, macOS, streaming services, and pretty much anything that has a battery or plugs into a wall. Oliver also covers mobile gaming for iMore, with Apple Arcade a particular focus. He's been gaming since the Atari 2600 days and still struggles to comprehend the fact he can play console quality titles on his pocket computer.