What Your Browser Reveals When Cookies Are Blocked

What does a browser fingerprint reveal?

A browser fingerprint is a collection of details about the browser and device you use. A website may combine those details into an identifier or pattern that helps it recognize a visitor again ⁴⁵.

A single detail, such as your browser version or language, may not identify you. A combination of details can be more distinctive, although the supplied sources do not establish how uniquely it identifies any particular person ⁴.

Which device details can be combined?

A website can receive basic information from a browser, including its version, operating system, preferred language and time zone. Scripts can also check other features, such as installed fonts, browser extensions and some hardware-related properties ⁴.

Canvas fingerprinting is one technique: code asks the browser to draw something, then uses characteristics of the result as another signal. The sources do not give a definitive list of signals used by every fingerprinting system ⁴.

Why can tracking continue after cookies are blocked?

Cookies store information in a browser. Fingerprinting uses details the browser or device makes available, so blocking cookies does not, by itself, remove every possible signal a site could combine into a fingerprint ⁴⁵.

Incognito mode is not necessarily a barrier either. One demonstration reports that its JavaScript-based method still produced a consistent nickname in incognito. Disabling JavaScript stopped that particular method, but the demonstration says network-based methods could still work ¹. This is an example, not a guarantee about every website.

Are fingerprints used for security or advertising?

They can be used for security. A fingerprinting provider says its technology can help identify patterns of suspected fraud or attempts to get around security measures, so a site can apply extra checks ³.

Fingerprinting can also raise privacy concerns if information about visits is joined with account details or shared under a site's privacy policy. A demonstration describes this possibility, but the supplied sources do not show how often such sharing happens or how widely information is combined across sites ¹.

What steps can reduce fingerprinting?

The sources do not identify a single measure that stops all fingerprinting. Disabling JavaScript can block techniques that depend on it, but may affect website features and does not stop network-based methods, according to the demonstration ¹.

Cookie blocking and incognito mode should not be treated as guarantees of anonymity. Reviewing a website's privacy policy can help explain what it says about collecting or sharing information, but a policy does not itself prevent collection ¹⁴.

BrowserScan is described as a tool for browser fingerprinting and privacy analysis ². The provided information does not establish how complete its analysis is or whether using it prevents a website from tracking a visitor.

What is not yet clear?

The sources describe fingerprinting methods but do not measure how widely websites use them, how accurate identification is across browsers, or how long a fingerprint stays stable. A commercial provider describes its own system as highly accurate, but the supplied material includes no independent measurement supporting that claim ³.

They also do not establish which current browser settings offer the best balance between privacy and website compatibility. Fingerprinting methods and browser features can change, so a demonstration or analysis tool cannot be assumed to cover every site ¹²⁴.