Even if you use anonymous browsing, block ads, or hide your tracks, some websites still monitor your every move online using a new web-tracking technique called Audio Fingerprinting.
This new Fingerprinting technique can be used by companies to distribute targeted ads, as well as by law enforcement authorities to unveil VPNs or anonymous users without the need to decrypt traffic.
Most of the technique you've met, but in another harmless form: the Shazam application uses it.
Researchers at Princeton University conducted a huge survey and discovered that Google, through too many domains it uses in its services, monitors users from 80% of all Top 1 million domains, using several tracking methods and techniques.
Of these, the latest tracking technology that researchers have identified is one that is based on capturing "fingerprints" of a machine's audio through the AudioContext API. For this: Audio Fingerprinting.
"All of the top domains, as well as 12 of the top 20, are owned by Google," the researchers note.
The AudioContext API does not collect sounds played or recorded by a machine but collects the sounds of each machine which are then used to create unique combinations of browser with the device.
The method has nothing to do with the device's microphone, as it is based on the way a signal is being processed.
A third-party tracker now uses the AudioContext API to send low-frequency sounds to the user's computer and then counts how much the computer needs to process the data, creating a unique fingerprint based on the hardware and software capabilities of the computer.
Top Web pages that use Audio Fingerprinting to keep you secret:
The researchers, Assistant Professor Arvind Narayanan and graduate student Steven Englehardt, created a page for live demonstration of the technique. So if you want to check the fingerprints of your device you can do it from the test page.
The technique of Audio Fingerprinting is not widely adopted but seems to use a number of different approaches that in combination "silently" monitor those who browse the Internet.
To conduct tracking and monitor trackers, researchers used a custom open source software called OpenWPM, which loads web pages in Chrome, Firefox and Internet Explorer, and monitors the collection of data on every page that is loaded.