Cover Your Tracks (by the Electronic Frontier Foundation)
Have you ever searched for a pair of shoes online, only to have ads for those exact shoes follow you around the internet for weeks? Most of us know that advertisers use cookies to track us. You delete your cookies, clear your history, maybe even turn on a VPN, and think you’re invisible.
But modern tracking is much sneakier than that.
Today, data companies use a technique called browser fingerprinting. Every time you visit a website, your browser hands over tiny pieces of information so the page displays correctly. When you bundle all those tiny details together, they create a highly specific, unique “fingerprint” that belongs only to your computer. Trackers can identify you across millions of other web surfers without ever needing a cookie or your IP address.
In fact, these data points have a 90% to 99% accuracy rate of identifying your specific machine out of millions.
What are websites actually learning about your computer?
When you load a webpage, your browser engages in a massive, split-second data exchange with the website’s server. It doesn’t just see your IP address; it scans your software, checks your hardware, and tests how your computer processes data:
Basic Identity: It logs your precise browser version (Chrome, Edge, Firefox) and your core operating system (Windows 11, macOS, Android).
Hardware & Screens: It checks your exact screen resolution, your monitor’s color depth, and even your device’s battery status.
Your Digital “Font Registry”: The site checks which specific fonts are installed on your hard drive. Because you have custom fonts from software you use (like Microsoft Office or Adobe), your unique list of fonts acts like a barcode.
Canvas Fingerprinting (The Graphics Test): A website can run a script that tells your browser to draw a hidden, invisible 3D shape. Because of tiny variations in your graphics card (GPU) and monitor drivers, your computer renders that image subtly differently than anyone else’s, creating a permanent mathematical tracking signature.
Audio & Peripherals: Sites can play a silent audio frequency to test your sound card’s signature, and check how many microphones, speakers, or cameras are plugged into your system.
Environmental Clues: It logs your precise timezone and checks if you are using an ad-blocker. Ironically, using a generic ad-blocker often makes you stand out more in a crowd because your signature looks unique.
You cannot easily block these scans because websites genuinely need this data just to display properly. If your browser blocked a website from knowing your screen resolution or language, the website would look like a broken, unreadable mess.
Test your defenses in 30 seconds
That’s where Cover Your Tracks comes in. Created by the digital privacy heroes at the Electronic Frontier Foundation (EFF), this free, non-profit tool lets you test your security defenses securely.
When you visit the site and click “Test Your Browser,” it simulates loading various hidden trackers and invisible beacons. It then gives you a plain-English report card showing if you are successfully blocking tracking ads, if you are stopping invisible tracking beacons, and exactly how unique your digital fingerprint is compared to millions of other users.
It is an eye-opening reality check for anyone who values their online privacy. If your results reveal that you’re leaving a wide trail behind you, the site provides excellent, simple recommendations on how to tighten your defenses (like using privacy-focused extensions or shifting to a fingerprint-resistant browser).
Don’t take your browser’s default privacy settings for granted! Go see how you look to the rest of the web.
Thank You!
I tested mine and all was well. I’m glad of that. A really good app to keep for future testing, thank you bunches for such a good thing.
After running this, I’m really confused — as opposed to my normal confusion. This program and my sys info say I’m running windows 10 but when I check for Windows 11 download or update, I’m told my computer is running Windows 11. What in the world is going on? Which do I believe and why?
I think you’re referring to user agent browser tags that say Win10. All major web browsers (Chrome, Edge, Firefox, Brave) purposefully freeze the Windows version in your user agent string as Windows NT 10.0, even when you are running Windows 11.
Breaking the Internet (Legacy Code)
When Windows 11 came out, browser developers feared a massive wave of website crashes. For decades, lazy web code used simple rules to check operating systems. If a website saw Windows NT 11.0, its old code might completely misinterpret it as “Windows 1” or simply crash because it didn’t know how to handle anything higher than 10. Because Windows 11 is built on the same core architecture as Windows 10, keeping the tag as 10.0 ensures old web tools and business software continue to work flawlessly without breaking.
Privacy & “Anti-Fingerprinting”
Every piece of specific information your browser shares creates a digital footprint. Advertisers and tracking scripts use things like exact OS versions, screen resolutions, and font lists to build a unique profile of your device (“fingerprinting”) to track you across websites. By forcing everyone on Windows 10 and Windows 11 to share the exact same Windows NT 10.0 string, you blend into a crowd of hundreds of millions of users, making it much harder for trackers to single you out.
I checked all the browsers I have installed. Chrome was fully protected; Firefox and Brave were partially protected. Cent Browser had 0. Nice to know which browser gives me full protection against trackers. Is there a way to stop all tracking on all browsers? Thanks. Blessings to you.
No way I know of even with a VPN.
Thank You for this.
I’m seriously worried about what I am getting at the moment. I’m not sure what to do about it.
I’ve used Cover Your Tracks and I have problems.
Margaret.
Almost everyone has problems because your browser tells a lot about you; it does not mean you’ll get hacked, it means you’ll see a lot of ads following you.