What is browser fingerprinting?
Browser fingerprinting is a tracking technique used to collect information about a user via their browser configuration. These include unique identifiers, such as the following:
Browser type and version
Downloaded fonts
Screen resolution
Device operating system
Installed plug-ins and extensions
Thus, fingerprints can identify users or devices that visit a particular website. Once a user is identified, and a unique profile is built, different organizations may advertise to them based on their preferences.
Browser fingerprinting is different from cookies, as outlined in the table below:
Differences between Browser Fingerprinting and Cookies
Browser fingerprinting | Cookies |
It collects data without user knowledge and consent. | It collects data with user knowledge and consent. |
The code snippet for fingerprinting is difficult to distinguish from website source code and hence, detection is hard. | Use of cookies is regulated and most websites are required to take permission for them. |
There is no way to delete browser fingerprints. | It can be deleted from the browser. |
How it works
Website owners and advertisers can add JavaScript code snippets to their websites. When a user visits the page, their browser data can be extracted, and a unique profile is built around this data. For example, a third-party vendor may be able to gauge a user's timezone, whether cookies are enabled, and if they're using a Tor browser. All of this data, compiled into a hash, can help track users' digital activity across the internet in a process called cross-site tracking.
Further techniques in browser fingerprinting include the following:
Canvas fingerprinting: A browser's Canvas API helps generate local images, drawings, and fonts. These are dependent on the underlying hardware's processing capabilities and are done silently without users' knowledge. The generated images are highly unique, revealing information about our font styles, graphics card, and operating system.
Audio fingerprinting: The browser forces our device to play audio sound and gathers information about the device's audio stack as well as sound hardware and software via the emerging sound waves.
Clock skew: This is a physical trait of devices based on hardware characteristics such as internal temperatures. It gathers unique information about a device remotely by measuring slight but observable differences in device clock speeds.
How to prevent it
Traditional ways to prevent tracking, such as using incognito modes and deleting cookies, do not work against browser fingerprinting. Therefore, the most effective way to mitigate this is by diluting our digital uniqueness through generalization.
This can be achieved by using anti-tracking services and anti-fingerprinting browsers such as Tor browsers that generalize users across most websites. Other browsers, such as Firefox have built-in mechanisms to prevent the execution of fingerprinting code snippets.
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