What are Browser and Device Fingerprinting?

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These days, most of us spend a good chunk of time online – whether it’s browsing the web, using apps, or staying connected on social media. With so much of our personal information floating around, privacy while using the internet has become a big concern.

In this discussion, we’ll check out how websites can uniquely identify your browser and device through “fingerprinting.” By the end, you’ll understand how all that behind-the-scenes snooping works and how to stay a little more anonymous. 

Google Chrome, Microsoft Edge, Firefox, Opera, Safari apps popular browsers on the screen iPhone

What is Browser Fingerprinting?

Browser fingerprinting is a technique websites use to identify the browsers of individual users uniquely. Even though you may think you’re browsing anonymously, your browser leaks a ton of details about your specific setup that can be used to build a unique “fingerprint” of your device.

Things like your browser name and version, installed plugins, fonts, system fonts, screen resolution – all of it gets factored in. It’s like taking all those identifiable traits and converting them into a long string of code that acts like a digital signature or fingerprint.

With that signature, sites can recognize your exact browser across multiple visiting sessions, even if you delete cookies each time. They don’t need you to log in to keep track of what you’ve looked at before.

This fingerprint information gets collected and sold by analytics companies so advertisers can precisely target you based on your browsing history. For example, if you looked at hiking gear last week but didn’t purchase it, outdoor brands might retarget you with ads reminding you of their deals.

Governments have also been known to use browser fingerprinting for surveillance purposes. So, even when you think you’re browsing privately, your fingerprint still leaves tracks that can identify and profile you online.

How Does Browser Fingerprinting Work?

When you visit a website, your browser automatically sends some basic information to the server, like your IP address, user agent string, and accepted languages. But browser fingerprinting digs deeper to collect additional clues that are more difficult to change.

It starts by examining your browser metadata – things like your screen resolution, installed fonts, plugins, and other configuration details. The coding language your browser is written in also factors in.

Then, it looks at subtle rendering differences between browsers. For example, how your browser renders images using the HTML Canvas element or creates cryptographic hashes. Slight pixel variances in these renderings provide extra fingerprint data.

Your system fonts and ActiveX/VBScript controls also contribute unique bits to your profile. Plus, any information accidentally exposed by WebRTC, like your local IP address, device name, OS version, and installed carriers.

All this collected data – from your basic browser info to tiny rendering anomalies – gets encrypted into a unique identifier string. No single item directly identifies you, but the combination is very hard for another user to duplicate exactly.

Each time you load a page, your fingerprint gets sent back to the server for databases to analyze and tie back to your previous visits and digital profile. Over time, this persistent digital fingerprint allows sites to recognize and track individual browsers silently beyond cookie data.

What is Device Fingerprinting?

Similar to browser fingerprinting, device fingerprinting refers to the process of uniquely identifying individual mobile devices based on technical details. Even without an account, apps can scan dozens of attributes about your phone to build a unique “digital DNA profile.”

Things like your device’s model, screen dimensions, installed fonts, browser user agent string, operating system version, available memory, and even sensors like the accelerometer all contribute to creating your device’s fingerprint.

Advertisers and marketers use this data for targeted ads and analytics. For example, if an app recognizes your fingerprint from earlier visits, it can retarget you with popups about new features to get you spending again.

Governments in some countries also allegedly use device fingerprinting for surveillance of dissidents. By matching fingerprints to known locations, they can quietly monitor citizens without gaining direct access to private data.

The main benefit for companies is that device fingerprints persist even after clearing app data/cookies, allowing continuous cross-device tracking as you use different phones. Your fingerprint remains attached to your digital habits and interests over time.

How Does Device Fingerprinting Work?

Think of your phone as a person with unique characteristics that make them identifiable. With device fingerprinting, apps analyze a variety of these traits about your device to fingerprint it essentially. 

When you visit a website or use an app on your device, certain anonymous information about what you’re using is collected automatically in the background. Things like your device type (computer, phone, tablet), operating system, screen size, and other basic technical details are noted.

The site also looks at programs you downloaded, such as specific fonts or browser add-ons. However, no personal details like your name or address are ever recorded – it only focuses on the technical specs of your device setup.

All this automatically detected information is then analyzed and combined in a unique way specific to the characteristics of your individual device. This results in a kind of digital “signature” or “fingerprint” being created just for your particular configuration.

You can think of this fingerprint as a unique tracking code that allows websites to recognize your device in the future, even if you clear cookies or cache from your browser. But it only works to identify your device, not personally identify you.

This fingerprinting method helps sites better understand how different users interact on various devices. It also helps security teams look for suspicious activity that might indicate potential fraud or hacking attempts.

For example, if someone purposely tried to disguise their tracks, their device fingerprint may look very similar to many others. But when matched with other contextual data, any anomalies could flag them for closer inspection.

server configuration command lines on a monitor

What Information Is Collected?

The type of info gathered during this fingerprinting process is all just technical stuff about your device setup – nothing personal like your name or contacts. It’s mostly gathering anonymous specifics about your machine’s setup. However, breaking down which details are noted may be more insightful. 

Canvas Fingerprinting

Canvas fingerprinting is an interesting way websites can identify your device by looking at tiny differences in how your browser draws pictures.

It works by using an HTML5 Canvas – this lets websites dynamically make little drawings in the code. When a site does canvas fingerprinting, it makes some basic doodles and shapes and sees how your specific browser renders them.

Even tiny details in how your browser shows fonts, spaces between pixels, or math behind the scenes when drawing can differ slightly from others. On their own, these little rendering quirks don’t mean much. But together, they create a unique fingerprint just for your browser/device combo.

It’s sort of like how no two people have exactly the same fingerprints – even little variations make each one one-of-a-kind. Canvas fingerprinting detects those micro differences in how your browser/device draws pictures to fingerprint it in the same way.

The cool part is this fingerprint sticks around even if you delete caches and cookies since it taps into how the actual software and hardware draw things at a low level. This makes it harder for people trying to hide what browser/device they use.


Local IP Address

Your IP address is like your unique home address on the internet. When you connect to websites or use apps, your device gets assigned a special number that lets your traffic be routed properly.

For device fingerprinting, sites look at your local or internal IP address – the number your device uses internally on your local WiFi or ethernet network at home. No two devices on the same local network will have the same one.

Even though you can’t lookup a location from a local IP like a public one, it still helps fingerprint you. That’s because factors like your network adapter, WiFi network name, and router settings sometimes subtly influence the number.

Over time, researchers found certain WiFi routers tend to dish out IP addresses with similar patterns. So, together with other fingerprints, your local IP gives sites an extra identifier for your individual device setup.

Font Fingerprinting

The specific fonts installed on your computer can also help fingerprint your device. Even though we all use the same basic fonts like Arial and Times New Roman, each device can have additional custom fonts, too.

When you visit sites, they’ll check which fonts are available on your browser. Things like freeware fonts you or other programs installed over the years, custom Apple fonts on a Mac, or fonts included with your Android version all vary slightly between devices.

Research has shown some fonts are far more common than others. So, together with everything else, sites can deduce even minor hints about your setup, like whether it’s Windows or MacOS, simply from the specific fonts installed being more typical for that system.

Device Details

To fingerprint your device, sites look at a few key details. First, they check out the basic stats, like whether you’re on a phone, laptop, desktop, etc. They’ll see brands like Apple, Samsung, and Dell and your exact model and screen size. It also checks what processor and graphics card it has, plus how much memory and storage it’s packing. 

As for software, they analyze all the nitty gritty deets about your operating system, like if it’s iOS, Windows, etc. Plus, your language/region settings and any default apps. Combining this with specific browsers, extensions, and plugins helps to improve the uniqueness. Your local internet address and default WiFi drivers also play a role.

How To Prevent Fingerprinting

There is a growing concern about how easily devices can be fingerprinted online. Here are a few approaches that can help you add a layer of ambiguity:

Use a VPN or Proxy

One way to avoid being uniquely fingerprinted is by routing your Internet traffic through a VPN or proxy server. This acts as a middleman between your device and the websites you visit.

By hiding your real IP address and location, a VPN/proxy immediately makes it much harder for sites to fingerprint you based on network-level clues. They no longer see your unique local network name or public internet address.

All traffic appears to be coming from the VPN/proxy server instead of your home/work network. This means things like default WiFi drivers and typical IP addressing schemes for your geography are no longer detecting you.

A good VPN/proxy will also allow you to spoof your apparent device location. So a website sees you connecting from somewhere else, adding mistaken context that confuses fingerprint profiles trying to pinpoint hardware-software traits to physical places.

Regularly changing servers further randomizes your digital fingerprint over time. It breaks any attempted linkage between sessions under different VPN addresses.

Periodically Clear Cache, Cookies and Reset Browser Settings

Clearing out your cookies regularly is helpful since those little trackers are what sites use to recognize your browser over the long run specifically. Wiping and resetting any plugins or permissions you’ve given also changes how your setup is identified. Additionally, deleting your cache frequently removes leftover clues in temporary files about your device specs that could fingerprint an older profile.

You can also erase your history to break the ties between browsing sessions under the same ID. This throws off any guesses they try to make about your preferences. Even little things like periodically changing your language or appearance settings allow for handy variations to your digital fingerprint. It makes the profile less static and unique each time one is extracted.

Update your Operating System and Web Browser Regularly

Ensuring your OS and browser are always up to date helps mix things up fingerprint-wise. As tech companies are constantly tweaking code and adding new stuff behind the scenes, even small things about your setup are evolving over time.

If you let your versions get outdated, then all the nitty gritty details that make up your digital profile also stay stale. But by staying caught up on upgrades, you keep even the tiny pieces in a constant state of slight change.

Use a Privacy-Focused Browser

Browsers that are built with privacy in mind from the start can give you an extra layer of protection against unique ID tracking. Most regular browsers like Chrome or Firefox will send many details about your activities that make you stick out online.

But browsers designed specifically with privacy enthusiasts in mind, like Tor or Brave, are coded to limit how much they blab about your setup. Things like what fonts you got installed, your screen res, time zone – all the nitty gritty stuff brands normally use to tell you apart gets kept much more hush-hush.


While no technique is completely foolproof, tweaking how your browser exposes itself and regularly mixing up the little details about your setup over time can muddy the waters of whatever profile advertisers are trying to compile on you. Remember, every bit of confusion and extra vagueness can help shield you from unwanted fingerprinting.

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