With online checker http://ipleak.com you can check browser for unique digital prints (fingerprints) that enable a website to identify your device.
What is browser fingerprinting?
A fingerprint is a complete set of all the available information about the system, the browser, and plug-ins, written as a unique ID number. It may look like this: 249821af43932314621f1246618ea8e1. Even if you change your IP address and delete all browser cookies, your device may be identified on the Internet by this number at any moment.
How to protect your device from getting identified by its fingerprint?
The device fingerprinting method employs the idea of entropy: the lower the entropy, the more your system information looks similar to that of other users and so can't be utilized to accurately identify your device on the Internet.
If you hide all information about your device, this will increase the entropy value, because the fingerprint of your device with all the data hidden will look too unusual. This can actually make tracking your device somewhat easier.
The best course of action is to mask the information about your browser and device with common setting combinations. This is done using special tools (e.g., Random Agent Spoofer for Firefox).
What is canvas fingerprinting?
The website can make your browser render a hidden text image or 3D graphics, which is then converted into a near-unique ID number.
This exploit is based on the fact that different browsers, operating systems, and video card exhibit slight differences when rendering the same element. The Canvas fingerprint identifies your devices in 90 cases out of 100, even after you change your IP address.
How to protect yourself from the Canvas fingerprinting?
Use special extensions to block the HTML5 Canvas element (for example, CanvasBlocker for Firefox, Canvas Defender or CanvasFingerprintBlock for Chrome). With such an extension installed, you can configure a list of trusted websites where the use of the Canvas element is allowed.
What is ETag and how to protect yourself from ETag identification?
ETag, or HTTP entity tag is a unique identifier, which is included in HTTP headers and stored in the browser cache along with images and other files.
When you go to a webpage, your browser sends the ETag to the website to see if the cache data needs to be updated. However, the ETag can also be used to identify your device.
To protect yourself, you need to clear all stored ETags along with the browser cache or use a private browsing mode.