Regain your privacy: pro tip week three

you are truly unique, are you?


The previous post I showed you how to manage your passwords in a better way. I hope it has been useful to you! Today I would like to give you some more insight into the data trail that you inevitably create when working online.

Think about the next idea: you are invited to a wedding of a friend and you decide to drive there. When you arrive you go in the parking lot and you see the cars of guests that have arrived before you. You see five modest cars, all black, same model and make; only the license plate is different. You also notice three regular grey cars, but you can't tell who owns which one. At last you see a yellow Ferrari with a custom license plate displaying "ITS ME" . You think; "that must be Peter, he is a bit bolder than the rest of us".

My point is not that I like yellow Ferraris, but that extravagant cars are like a unique fingerprint, and modest cars are like a cloak. The same is true online, where you replace the idea of cars with web browsers.

Get to know your online fingerprint

A lot of people express themselves consciously through their car. Brigth colors, lowered suspension, a message on the license plate, you name it. The same happens with web browsers. While most people start out with the browser that comes standard with the operating system (like Safari for Apple or Edge/Internet Explorer for Microsoft), a lot of them evolve into using a custom setup that better suits their daily usage.

A lot of my colleagues like to use Firefox (developed by Mozilla) or Chrome (developed by Google), and personally I think Firefox works really well for 99% of the time.

Those web browsers can be customized (like cars) with themes, add-ons, extensions and profiles for every purpose and mood. It is often useful to have a customized web browser, but did you know that a lot of website operators can also recognize you by the customizations you have set?!

When you open a web browser (whichever one you like) it is like you step inside your car and go out onto the internet highway. When you visit a website (arrive at your destination) the website owner sees your web browser (or car) and can start to make all sorts of assumptions about you.

There is a really good website to test the fingerprint that your web browser emits, , created by the Electronic Frontier Foundation (a non-profit that stands up for digital privacy rights). Go to the website and click "Test Me" to see how unique you are.

Understanding the fingerprint results

When the test is completed you will see a page with results. At first it might come across confusing what all those numbers are, so I'll try to explain it as simple as possible.

The test calculates how much web browsers have the same fingerprint as your browser, for example 1 in 5000. The more browsers that have the same fingerprint as yours, the better. If a small number of web browsers have the same fingerprint as yours, this means you have a quite unique fingerprint, and are easy identifiable.

The test also calculates how many bits of identifying information your browser is leaking. The more bits you leak, the more pieces of information a website provider (or underlying tracker) can discover about you.

I did the test with two web browser installations (both Firefox), one setup for privacy and one without special precautions. The first one was similar to 1 out of 6.000 browsers (on a total of 270.000), and leaked 12 bits of information. The other one was unique, and leaked 18 bits of information.


So how can websites see this information? The answer is javaScript! That's a programming language especially popular for the Internet. A website hosting JavaScript code can request information from your browser like your time zone, your language or the system (Windows/Apple) you are using.

A privacy conscious approach

To limit the amount of information you are giving away you can do a few things. Doing one of them will already help a little bit, doing all of them is better of course.


These three simple measures will make it harder for websites and trackers to collect information about you, and you are in control again over the info you share about yourself with strangers. If you are curious to know more be sure to check this space regularly, or contact me for personal advise.