Variability in different math libraries, which are used when audio is produced through browsers, were once high enough to provide a massively large number of uniquely different signatures when combined with different CPUs and other system differences. After the audio soundprinting technique became well known, Firefox implemented a fix, starting in version 118 released in 2023. Beginning then, the browser used its own unique math libraries, rather than relying on ones that shipped with the OS it ran on. Tom Ritter, a Firefox developer who has also volunteered for the Tor Project, said the move to constant libraries reduced the entropy enough to stop the technique from working.
The technique is ineffective in Chrome because it, too, ships with its own libraries, a Google spokesman said. Safari users are likely safe for the same reason, although Apple didn’t immediately provide confirmation of that.
An artifact from years past
AliExpress’ use of an obsolete fingerprinting method raises the question: Why is it bothering to use it? The likely answer has to do with the more than a dozen other fingerprinting methods the online retailer is using. Callaghan said the other techniques included:
canvas rendering and toDataURL()
