You’re constantly leaving your fingerprint all over the internet. You leave it with the personal information you share willingly, the personal information you share unknowingly, and with the mountain of data that gets sent to each website you load. Maybe you know a thing or two about privacy and decided to pick up a VPN to keep your browsing private. Even then, you’re a lot less private than you expect.
Your PC and the millions of servers that make up the internet share a lot of information, but the vast majority of it doesn’t fall under the umbrella of personally identifiable information. For instance, a website might know that your default system language is English, so it loads the English version of its website. That’s not personally identifiable. Sure, the website knows English is your preferred language, but the same is true for hundreds of millions of others.
In isolation, this data doesn’t mean much of anything. Together, however, it can identify you. This is the data that makes up your browser fingerprint, and it can be used to track you across the internet, even when visiting different websites, opening different browsers, and when you have a VPN turned on. Here's everything you need to know.
What’s a Browser Fingerprint?
AmIUnique via Jacob Roach
The best way to describe a browser fingerprint is to show you. Go to AmIUnique and wait a minute or two for the test to run. You can see all the information your browser sends, as well as a similarity score based on all the results in the AmIUnique database. If you can’t be bothered, my fingerprint on a PC running Windows and Chrome—by far the most common operating system and browser—is unique out of over 4 million entries in the AmIUnique database.
The Electronic Frontier Foundation (EFF) has its own fingerprinting tester called Cover Your Tracks, and it puts the information in a slightly different way. I’m using Linux on my PC, and according to this test, that’s true of about one out of six PCs the EFF has tested; not unique at all. However, my WebGL fingerprint—details about how graphics are rendered in my browser—is very unique. Only one in over 33,000 browsers has the same WebGL fingerprint.
Your browser fingerprint is a collection of innocuous information about your PC that, when put together, is unique enough that it could identify an individual. Some of the components of your browser fingerprint include your computer's hardware, your browser and version, the various versions of software you have running in your browser, the fonts you have installed on your PC, your time zone, your system language, your keyboard layout; the list goes on. Out of the dozens of pieces of information, none of them could identify you individually. It's when this data is bundled together that your fingerprint becomes unique.