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Graphics Cards: the Future of Online Authentication?
Gunkerty Jeb writes "Researchers working on the 'physically unclonable functions found in standard PC components (PUFFIN) project' announced last week that widely used graphics processors could be the next step in online authentication. The project seeks to find uniquely identifiable characteristics of hardware in common computers, mobile devices, laptops and consumer electronics. The researchers realized that apparently identical graphics processors are actually different in subtle, unforgeable ways. A piece of software developed by the researchers is capable of discerning these fine differences. The order of magnitude of these differences is so minute, in fact, that manufacturing equipment is incapable of manipulating or replicating them. Thus, the fine-grained manufacturing differences can act as a sort of a key to reliably distinguish each of the processors from one another. The implication of this discovery is that such differences can be used as physically unclonable features to securely link the graphics cards, and by extension, the computers in which they reside and the persons using them, to specific online accounts."
If this fingerprint is orders of magnitude beneath manufacturing controls, are the researchers sure that it persists over long time frames?
Will that graphics card have the same fingerprint the first day it is purchased as it does 2 years later after putting in hundreds of hours at high temperatures playing accelerated games?
The WPI report confirms what most everyone suspects: Reading from an uninitialized SRAM returns mostly noise, about 50/50 (but not exactly) 1's and 0's, and highly dependent on temperature. I think what they're saying is something like "Look at uninitialized memory, whose values are apparently random 1's and 0's, and somehow compute a unique fingerprint that is stable for this device, but different from all other devices". I'm not sure that's actually possible. I can't think of anything on chips that would produce "random"-looking data and which wasn't highly temperature dependent.
Even if a clever algorithm could "fingerprint" an SRAM device, others have already pointed out all the ways to break this. It's simply a slightly more complex MAC address, and will likely be easy to effectively clone. It's like printing a password on paper in special red ink that only you have, and then saying no one can log in to your system (by typing the password) since they can't replicate that red ink. Umm, the special red ink is a red herring. All you need is the password.
I don't think there's really anything here. There's no details at the PUFFIN site.