Browser fingerprinting – What is it and how can I protect myself?

You are not like the others. You are unique. What sounds like a harmless, albeit cliché-laden motivational slogan can take on a threatening undertone in a discussion about data protection on the Internet. Because the uniqueness of your identity makes you vulnerable: To advertisers, data traders and abusers. Your personal fingerprint on the web makes sure of that.

What is a browser fingerprint?

You may think you’re anonymous on the Internet. But every click you make from your gadgets reveals who you are. Whenever you go online, your device provides the pages you visit with very specific data. This can be information about your operating system and settings, for example. You can even draw conclusions about your hardware.

When someone uses this data to determine your identity, it’s called browser fingerprinting. Websites do this, for example, to recognize your browser, plugins, language, screen resolution, time zone, and other settings. This helps them identify unique visitors and follow their online activities.

Browser fingerprinting: good or bad?

Your data is, of course, found food for the international marketing machine. Based on it, websites present you with targeted ads to encourage consumption. Data thieves and malicious malware attackers also use the information. But there are more useful reasons for which this data is collected. Banks, for example, may rely on your fingerprint on the web to prevent fraud. So browser fingerprinting is not bad per se – but it still provides plenty of reasons for concern.

What exactly is fingerprinting?

The name doesn’t come from nowhere: once a digital fingerprint is created, it can be used to accurately establish your identity. According to Mozilla “the process is able to correctly identify users 99% of the time.” Even if you block cookies, surf with VPN, or adhere to other security measures so often recommended on the web, your digital fingerprint can give you away.

Website operators can recognize and track you on the Internet using your browser fingerprint, for example, to show you individualized advertising or analyze your surfing behavior. To do this, they use a technique called browser fingerprinting.

This is how it works: When you open websites with your browser, data about the configuration of your browser is also exchanged. There are two forms of fingerprinting:

  • Passive fingerprinting: information that is automatically transmitted from the computer to the web server.
    Example: IP address, browser used
  • Active fingerprinting: Information that can be read by JavaScript or Flash.
    Example: operating system information, time zone, fonts, resolution, window size.

This information can be combined into a browser fingerprint to identify you as a user. Why is this? Because most users customize their browser. In Firefox, for example, this can be done with various plugins and addons, which in Chrome are also known as extensions.

So if your browser is unique on the Internet due to its configuration with plug-ins and add-ons, it can always be uniquely assigned and you can be recognized as this one surfer – completely without your actual personal details – only via your browser and operating system settings.

How do I find out my personal browser fingerprint?

On websites like Panopticlick and Am I Unique you can find out how unique your digital fingerprint is. Test your browser and find out if you are easily identifiable – and need to take action. It also has a tool on offer – with our Browser Privacy Check you can see what traces you leave behind while surfing.

Why should I protect my browser fingerprint?

Where personal data is collected, there is always a risk for misuse. Unlike other factors of identification such as your IP address, your digital fingerprint is invisible and therefore harder to protect. So many users don’t even know they’re sharing your data. Perhaps companies sell this data to third parties to make profit from it. Malware attacks can also become more effective with the personalized data.

How can I effectively protect myself from browser fingerprinting?

The bad news first: it is almost impossible to completely protect yourself from fingerprinting. However, you can mitigate your fingerprinting with a number of methods.

Use your browser in incognito mode

The easiest way to reduce your fingerprint is to browse in incognito mode. Almost every browser offers this feature. When you visit websites in private mode, they are not saved in your browsing history. Your browser profile is set to a certain default, which is the same for all users in incognito mode. Therefore, the digital fingerprints of these users look similar – and their uniqueness decreases. However, this method is not particularly effective because browser fingerprinting involves a lot of other data that incognito mode does not affect.

Surf with the Tor browser

  • If you are serious, you should change not only the mode, but the whole browser right away. The Tor browser is preconfigured so that the digital fingerprint of all users is identical. In addition, the browser blocks JavaScript very effectively.
  • However, depending on which features are individually activated in the Tor browser, it is still possible to draw conclusions about your digital identity. In addition, the Tor browser is less user-friendly, especially for non-experts.

Disable JavaScript

Through JavaScript, websites can collect plugins and other information that sharpen the profile of your digital fingerprint. You can either disable JavaScript manually through your browser, or use tools like NoScript or AdBlock Plus use them. However, because many websites rely on JavaScript, disabling it could severely impact your browsing experience.

Disguise your IP address with a VPN

  • With a VPN (Virtual Private Network), you can access a self-contained, secure network via a secured tunnel and thus conceal your IP. How exactly this works, and which providers there are, we explain here. As an intermediary for your data, the VPN ensures that web servers do not come into contact with your IP address.
  • However, the IP address is only one factor of your identity, and browser settings, on the other hand, are not concealed by a VPN. Therefore, a VPN alone is not an effective protection, and is only beneficial in conjunction with other methods – for example, disabling JavaScript.

Use special privacy software and extensions

Privacy is a constant issue for software developers as well, and numerous vendors and extensions promise effective help. Privacy Badger for example, blocks certain domains that use fingerprinting technologies. Disconnect works in a similar way. Together with a strong adblocker, these extensions help protect your identity on the web from malicious domains. Browser fingerprinting: the perfect protection does not exist As you have seen, there is no absolutely watertight protection against browser fingerprinting. Each of the measures presented has advantages and disadvantages.

For better protection, you can combine the different options, but especially for regular Internet users, the effort might be too much. Nevertheless, you should try to keep your digital fingerprint as small as possible. Even software that everyone should use anyway – adblockers or anti-malware, for example – can make a big difference. Take the measures that seem most sensible to you – and see how much your browser fingerprint has been reduced in the before-and-after comparison on Panopticlick or Am I Unique.

Browser fingerprinting – What is it and how can I protect myself?
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