User Tracking & Browser Fingerprinting
When users clear cookies and use a VPN, websites can still attempt to identify them through "browser fingerprinting." This technique combines many different data points from a browser to create a unique and stable identifier, even without storing any data on the user's computer.
1994: The "cookie" is invented, becoming the primary tracking tool.
2012: "Canvas Fingerprinting" is demonstrated, showing how unique graphical rendering can be used for high-accuracy tracking.
Present: A major privacy battleground. Browsers actively implement anti-fingerprinting measures while trackers research new techniques.
Core Fingerprinting Vectors
No single piece of information is unique, but combining them creates a highly specific profile.
- User Agent & HTTP Headers: Browser, OS, language preferences.
- Screen Information: Screen resolution, color depth, pixel ratio.
- Installed Fonts: The list of fonts available to the browser.
- Canvas & WebGL Fingerprinting: Rendering graphics to capture minor differences in GPU and driver hardware. This is a very powerful vector.
- AudioContext Fingerprinting: Using the Web Audio API to capture unique signatures from a device's audio hardware stack.
Defensive Measures: Privacy-focused browsers like Tor Browser and Brave have built-in anti-fingerprinting defenses (e.g., spoofing values, adding random noise). Extensions like uBlock Origin and Privacy Badger also help block known trackers.