Topic: AudioContext Fingerprint
A wide-scale study of online trackers carried out by researchers at Princeton University has identified a new technique being used to try to strip web users of their privacy, as well as quantifying the ongoing usage of some better-known tracking techniques.
The new technique unearthed by the study is based on fingerprinting a machine’s audio stack via the AudioContext API. So it’s not collecting sound played or recorded on a machine but rather harvesting the audio signature of the individual machine and using that as an identifier to track a web user.
AudioContext Fingerprint Test Page