Browser Fingerprinting

Browser fingerprinting creates unique identifiers from seemingly innocuous browser properties.

Fingerprinting data sources

• User agent: Browser, OS, device type.
• Screen resolution: Display dimensions.
• Installed fonts: Detectable via CSS/JavaScript.
• Plugins: Flash, Java (mostly deprecated).
• Canvas/WebGL: Rendering differences.
• Audio context: Audio processing variations.
• Timezone/language: User preferences.
• Hardware: CPU cores, GPU, battery.

Fingerprint uniqueness

• Combination of 10+ attributes = highly unique.
• 80-90% of browsers have unique fingerprints.
• Persists across browsing sessions.
• Survives cookie deletion.

Use cases

• Fraud prevention: Detect suspicious behavior.
• Bot detection: Identify automated browsers.
• Analytics: Track users without cookies.
• Access control: Device-based authentication.

Privacy concerns

• Users can't easily clear fingerprints.
• Tracking without consent.
• Difficult to detect and block.

Defenses

• Tor Browser (uniform fingerprint).
• Privacy-focused browsers (Brave, Firefox).
• Browser extensions (Canvas Blocker).
• Disable JavaScript (breaks many sites).