Lesson 3 of 5
Browser fingerprinting
Identification without cookies.
6 min read
Fingerprinting builds a stable ID from properties the browser exposes: screen size, fonts, GPU, language, timezone, audio context. Combined, these properties are usually unique to a single device.
Fingerprinting cannot be 'blocked' the way a cookie can be deleted. Defences focus on reducing entropy: standardising fonts, lying about screen size, randomising canvas output. NovaBlock blocks known fingerprinting scripts at the network layer, which is the most effective real-world defence.
Key takeaways
- Fingerprinting works even when cookies are disabled.
- Combined properties are usually unique per device.
- Blocking the fingerprinting script is more effective than randomising values.