New W3C Proximity Sensor API Can Be Used for User Fingerprinting

A new API currently developed by the World Wide Web Consortium (W3C) called the Proximity Sensor API would allow websites and advertisers to query the position of nearby objects next to your smartphone or tablet.

As mobile devices evolved, so did their technical capabilities. Nowadays, when you lift your phone to your ear, the screen usually goes dark because the device uses the camera to tell if you've put it next to your ear.

Rear and back cameras, movement sensors, accelerometers, and many other high-tech sensors can let a smartphone, tablet, or Internet of Things device know where you are in the room, or where are other objects like walls, doors, etc..

Because most of these sensors provide API interfaces, the W3C has begun work on a generic JavaScript-based API that will let websites query your device, and tell it how far are nearby objects. The W3C describes this new feature as below:

[CITATION]The proximity level is reported as the distance (in centimeter) ...