All About Unique Browser Fingerprints

Browser fingerprints are unique profiles created from your computer’s settings, allowing websites to track you even without cookies. Browser fingerprinting is an alternative to cookies, offering several advantages for those who want to identify users online.

1) Cookies vs. Fingerprints: The Main Differences

Cookies are a fundamental part of many online operations and are one of the main tools website owners use to track user activity. However, this method is becoming outdated and less effective. Today, users can easily disable cookies or use Incognito mode, which only saves cookies for the current session, making it harder for sites to track them. Additionally, users can see which cookies are stored and who sent them, giving them some control over their privacy.

Fingerprints, on the other hand, work differently. This technique analyzes information your browser sends to websites—such as language settings, installed system fonts, time zone, screen resolution, installed plugins, software versions, and more—to create a unique profile, much like a fingerprint. Even if cookies are deleted, a website can still recognize a user based on their browser fingerprint.

2) Changing Your IP Address Won’t Protect You from Fingerprinting

Fingerprints can replace cookies, and many websites actively use them. Ironically, privacy advocates who tweak their browser settings to avoid identification may actually make themselves more unique and easier to track. Studies show that computers with standard browser settings are similar to about 875,000 other users, making precise identification difficult. However, browsers with unique settings stand out as one-of-a-kind among millions.

Dangers of Browser Fingerprinting

• Privacy Threat: Fingerprints are much harder to defend against than cookies, and users often don’t even know they’re being tracked. Your computer is tagged with a unique digital hash based on your settings, which can be used to identify you on future visits.
• Global Identifier: Fingerprints make you recognizable not just on frequently visited sites, but across the web, even if you change your settings.
• Regenerating Cookies and Exposing IP: Some sites use Flash LSO super cookies to restore deleted cookies. Browser fingerprints can help recover cookies and identify users by their network data, making cookie deletion ineffective.
• Independence from Cookies: Fingerprinting can work even if cookies are completely disabled.

3) Research, Methodology, and Results

Researchers have studied how browsers are identified by collecting all possible characteristics that can distinguish one browser from another. Eight main parameters are usually enough for fingerprinting. Most tests used standard browser settings, but some also looked at unique configurations, like blocking JavaScript and Flash.

4) Untested Settings

• Some settings weren’t tested due to measurement difficulties or time constraints, such as full use of Microsoft ActiveX, Silverlight API, or identifying users by CPU type.
• Frequently changing parameters like geolocation and dynamic IPs were not included.
• Browsers that rely entirely on user preferences for operations were not tested.

The main work involved mathematical analysis to check how unique a browser becomes after changing its default settings. The fingerprinting algorithm used a concept called “surprisal,” where each piece of information is treated as a variable. The more variables remembered, the more recognizable the browser becomes.

Researchers found that changing your IP address rarely affects your fingerprint—only 4.6% of changed IPs altered the browser’s uniqueness. In most cases, other data was used for identification. Out of 321,155 addresses tested, 83.6% of browsers were unique, 8.1% were “not uncommon,” and only 8.2% were relatively protected from identification. Overall, 92% of browsers online are unique.

Browsers with various plugins, like NoScript, were less recognizable (uniqueness dropped to 40–50%), but using plugins can sometimes increase uniqueness if not configured carefully. Windows users are more vulnerable to fingerprinting than those on OS X or Android.

Stability of Browser Fingerprints

There are ways to make your browser less unique, such as regularly updating it, using common plugins, setting a standard screen resolution, and removing unusual fonts. If you don’t visit a site for a while (at least 2.5 weeks), your browser’s uniqueness can decrease by 30% or more. Changing your time zone can also help reduce uniqueness.

Additional Tracking Methods

Websites can track users through subtle details, like plugin version numbers (including microversions, e.g., 1.4.0.333), which increase uniqueness. Adobe Flash is particularly problematic, as it can reveal detailed font lists in a unique order, making your browser more identifiable. Disabling updates can help, but it’s not always practical since some system components need updates for security and functionality.

Testing Your Browser’s Uniqueness

You can test your browser’s fingerprint at panopticlick.eff.org. Click “Test me” to see how unique your browser is. If the results are unsatisfactory, adjust your settings and retest until your browser is less unique. It’s recommended to do this at least once a month, as changing settings can increase your recognizability.

Protection Methods

While fingerprinting is more dangerous for privacy than cookies, there are ways to reduce your browser’s uniqueness:

• Disable Flash, JavaScript, and WebGL to make fingerprinting harder (though this may affect website functionality).
• Use a combination of disabling Flash and Java with plugins like NoScript for better balance between privacy and usability.
• Use plugins like Ghostery to block cookies and reduce uniqueness.
• Control which scripts run in your browser using plugins for Chrome or Firefox that require your permission before executing scripts or sending data.
• Manage updates manually to avoid introducing unique elements, but be careful not to compromise system security.

Mozilla Firefox Add-ons

Firefox offers strong privacy tools, such as the NoScript plugin, which blocks Flash, JavaScript, Java applets, and other potentially dangerous elements. You can whitelist trusted sites for convenience. NoScript is cross-platform and protects against XSS attacks.

The User Agent Switcher extension lets Firefox mimic other browsers (like Chrome, Opera, or Internet Explorer) and even different operating systems. However, using it to fake your OS can actually make you more unique, as few users do this. Similar tools exist for other browsers, but they work best with Firefox.

Conclusion

1. Browser fingerprinting is a unique tracking system based on information from your browser.
2. It collects a wide range of data, including language, screen resolution, plugins, and cookie settings.
3. Deleting cookies is not enough; changing browser and system settings is more effective, but avoid making your setup too unique.
4. Research has uncovered both protection methods and sophisticated tracking techniques, such as microversion reporting and font list errors.
5. Fingerprints become less effective if you avoid a site for at least 2.5 weeks.
6. Complete protection is impossible, but you can minimize risk by using special plugins, disabling scripts (especially Java and Flash), and controlling updates. Using Tor is one of the best options.
7. Firefox offers strong privacy tools: NoScript disables revealing scripts, and User Agent Switcher can mask your browser (use with caution).