Your graphics card could be used to track you across the web regardless of cookie consent

pcgamer.com:

Telling a website to stick its cookies someplace else might not be enough to keep it from tracking you across the web—there are other identifiers that can help narrow down who you are and what you're doing as you travel the silicon superhighway. These techniques rely on tracking the exact configuration of hardware you're running inside your PC, though researchers suggest this form of hardware tracking could be done with even greater accuracy through something known as GPU fingerprinting.

Outlined in a research paper [PDF warning] from co-first authors Tomer Laor of Ben-Gurion University and Naif Mehanna from University Lille, CNRS, and their respective teams (via Bleeping Computer), the technique nicknamed DrawnApart takes advantage of minor differences in a user's GPU behavior to uniquely identify them across the web.

That could lead to persistent tracking by, what the researchers call, «less scrupulous websites» that potentially jeopardises existing privacy protections on the web, such as cookie consent.

The DrawnApart technique works by not only noting the GPU and other hardware in use by a PC, but actually honing in on a given GPU's specific characteristics. In the researchers' own words, «we harness the statistical speed variations of individual EUs in the GPU to uniquely identify a complete system.»

To do that, the researchers use WebGL to target the GPU's shaders with a sequence of drawing operations that are designed to be sensitive to differences across individual EUs. The resulting vector, called a trace, contains a sequence of timing measurements that the team have generated. 

The differences in the resulting trace information is then able to identify, or fingerprint, different GPUs, even if they're the same