Ninhydrin (Spanish: ninhidrina) is a chemical used in forensic science to uncover fingerprints on surfaces. This Web extension for Chrome and Chromium-based browsers uncovers canvas fingerprints generated by websites to track users. Please note: this Web extension does not prevent canvas fingerprinting. The development of this Web extension has been discussed in the paper Uncovering Canvas Fingerprinting in Real-Time and Analyzing Its Usage for Web Tracking.
- Clone or download the repository to your local drive
- Open Chrome and navigate to More tools -> Extensions
- Enable Developer mode (switch on the upper right)
- Click on Load unpacked
- Select the downloaded repository and click Open
When you browse the Web, the extension will show you if and how many canvas fingerprints have been generated by the website you currently visit. When clicking on the fingerprint icon (see Figure 1), a popup is shown in which the generated images can be seen. You can view all canvas fingerprints captured by Ninhidrina by clicking in the popup (at the bottom) on the View all button. The collection of images is opened in a new tab (see Figure 2).
Figure 1
Figure 2
The development of the Web extension and results of an analysis that had been carried out with the extension are discussed in the paper Uncovering Canvas Fingerprinting in Real-Time and Analyzing Its Usage for Web Tracking by Raschke and Küpper (2018). You can access the paper by clicking on this link.