Apple blocks access to Safari sensor data in iOS 12.2

Safari 12.1 in iOS 12.2 no longer allows sites to access sensor data. As a result, sites can no longer see without permission whether users are moving the phone when they have the page in the foreground.

The change was mentioned in the release notes of Safari 12.1 that Apple put online last week, but only became apparent after an article from Digiday. Access to sensor data is turned off by default, while users can turn it on in the settings on iOS.

The change appears to be a response to a paper published last year, which found that a small fraction of the top sites on the Internet are using sensor data for browser fingerprinting. Apple has put the feature under “Security and Privacy,” indicating that it’s a change to enable it.

Digiday’s article zooms in on the implications for ad companies and developers of ar applications in the browser. It’s still unclear whether site owners will be able to show users a pop-up requesting permission, as is currently the case with the location or the camera.

Apple has not yet released a public explanation of the feature, including an explanation of exactly what it is intended for and how site owners can modify their code for it. Apple has released iOS 12.2 with Safari 12.1 as a developer test version. The stable version will probably follow in a few months.

The toggle (left) and its effect on data the site gets. Source: 9to5Mac