AudioContext Fingerprinting

AudioContext fingerprinting is a browser fingerprinting technique that uses the Web Audio API’s AudioContext to generate a unique identifier based on how a user’s device processes and renders audio signals. By creating and analyzing subtle audio signals, differences caused by hardware, operating system, browser versions, and audio drivers produce a distinctive “fingerprint.” This fingerprint can be used to track users across websites without relying on cookies or traditional tracking methods.

Also known as: Web Audio fingerprinting, Audio fingerprinting (in the context of browser tracking)

Comparisons

• AudioContext Fingerprinting vs. Canvas Fingerprinting: Both rely on hardware and software differences, but audio fingerprinting focuses on sound processing, while canvas fingerprinting uses visual rendering.
• AudioContext Fingerprinting vs. Cookies: Audio fingerprinting passively collects device-specific data, unlike cookies which store data explicitly on the user’s device.

Pros

• Bypasses cookie blocks: Effective for identifying users who block or clear cookies.
• No extra permissions: Does not require any special permissions or plugins.
• Security boost: Helps websites enhance security by detecting fraud or suspicious behavior.

Cons

• Privacy invasion: Raises significant privacy concerns due to covert tracking.
• Tough to stop: Difficult for users to prevent without disabling or restricting canvas functionality.
• Enhanced tracking: Can be combined with other fingerprinting methods to increase tracking accuracy.

Example

A website generates a unique fingerprint by sending a subtle audio signal through the browser’s AudioContext and analyzing the resulting output waveform. This fingerprint distinguishes users based on differences in their audio processing setup, enabling the site to recognize repeat visitors even in private browsing or with cookie restrictions.