Fingerprinting is a digital tracking technique that enables websites to identify a user via the technical characteristics of their browser, without using cookies.
- Fingerprinting identifies users via 13 technical characteristics of the browser without storing cookies
- Automatically collects: user agent, screen resolution, installed fonts, plugins, time zone and canvas footprint
- Advertisers exploit this technique to circumvent cookie blocking and create persistent cross-device profiles.
- Allows advertising tracking, audience measurement and personalization without explicit consent
- Protection: use Firefox with private browsing, Privacy Badger/uBlock Origin extensions, disable JavaScript and limit plugins
- Tor Browser offers best protection by standardizing user fingerprints
- Paradoxically, modifying your footprint can make you more identifiable.
Fingerprinting is a probabilistic technique designed to uniquely identify a user on a website or mobile application using the technical characteristics of their browser. Unlike cookies, this method does not store any files on your device.
Browser fingerprinting automatically collects thirteen key attributes from your web browser. HTTP headers transmit your user agent, revealing your operating system and browser version. JavaScript APIs access system information via window.screen and window.navigator objects.
Your browser exposes a number of discriminating data:
- Screen resolution and color depth
- Complete list of installed fonts
- Detectable plugins and extensions
- Time zone and location settings
- Operating system version
Canvas fingerprinting generates a unique visual fingerprint based on your graphics hardware. This technique exploits rendering differences between graphics cards and drivers to create a stable identifier.
Fingerprinting scripts collect this information without your explicit consent. According to the CNIL, such collection requires prior informed consent. However, many websites continue to use this method to track Internet users.
This technique identifies users even when cookies are blocked, creating a persistent digital fingerprint that follows your online movements without leaving any detectable traces on your system.
Websites collect 13 key attributes to create your unique fingerprint. This technical information reveals your identity without leaving any traces on your device.
Your browser automatically transmits the user agent via HTTP headers. This data reveals your operating system, browser version and sometimes the exact model of your device. Chrome on Android exposes more information than Firefox, which uses a generic user agent.
JavaScript APIs retrieve your screen resolution, color depth and display settings via the window.screen object. This data varies according to your hardware and personal settings.
The list of installed fonts is the most discriminating attribute. This information depends on your operating system and installed software. Flash plug-ins easily reveal these fonts.
- Time zone and location settings
- Detectable plugins and extensions
- Resolution and graphics capabilities
- Browser language and encoding
Canvas fingerprinting generates a unique image based on your graphics hardware and drivers. The Electronic Frontier Foundation tests your uniqueness with these techniques.
Atypical operating systems like FreeBSD make identification immediate. Emojis vary from manufacturer to manufacturer and reveal precise information about your device.
Smartphones offer less diversity of attributes, as they lack plug-ins. However, mobile tracking techniques remain highly effective.
Advertisers exploit fingerprinting to circumvent users' blocking of cookies. This technique enables them to keep tracking Internet users even when they refuse traditional cookies. Companies such as BlueCava, AddThis and Revenviews use this method to reinforce their advertising tracking.
Programmatic advertising takes advantage of this technique to create persistent user profiles. Advertisers can track users across multiple devices and websites. This cross-device approach gives them a complete view of the user journey without relying on cookies.
Fingerprinting enables advertisers to measure audiences and collect analytics without explicit consent. Unlike cookies, this technique does not require user acceptance. Scripts automatically collect technical information on each visit.
Companies use this method to combat advertising fraud and detect bots. The unique fingerprint identifies false clicks and artificial interactions. This application helps protect advertisers' advertising budgets.
Fingerprint-based content personalization represents another major commercial use. Websites adapt their content according to the technical characteristics detected. This study on the effectiveness of Apple's App Tracking Transparency shows how companies are circumventing the new tracking restrictions.
Google updated its privacy policy in 2015 to mention the use of "technologies similar" to cookies. This vague wording masks the web giants' use of fingerprinting.
Protecting privacy against fingerprinting requires a multi-layered approach combining browser configuration and specialized tools.
Firefox offers the best native protection against fingerprinting. The browser blocks fingerprinting scripts by default in its private browsing modes. Safari and Edge also offer limited protection, while Chrome is more permissive.
Disable JavaScript on non-essential sites to reduce the amount of information exposed. Flash plugins and other extensions increase your unique fingerprint. Keep their number to an absolute minimum.
The Privacy Badger, uBlock Origin and Ghostery extensions block many known fingerprinting scripts. However, these tools do not detect new techniques. Canvas Blocker specifically prevents the collection of visual fingerprints via the Canvas API.
A VPN modifies your IP address but does not mask your browser's fingerprint. The Tor browser remains the most effective solution, standardizing user fingerprints. It disables JavaScript by default and randomizes certain settings.
Change browsers regularly and clear your browsing data frequently. Use virtual machines for sensitive activities. Avoid non-essential extensions that reveal information about your operating system.
Complete protection against fingerprinting remains a complex issue, as changing your fingerprint can paradoxically make you more identifiable.
Fingerprinting represents a complex threat to digital privacy. Users now need to combine several protection strategies: configuring secure browsers, using anti-tracking extensions and staying informed about new online tracking techniques.
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