Interesting idea but it didn't accept me the first 3-4 times I tried to draw the path on laptop trackpad - going slow led to it failing before I was finished, going fast led to messy paths that were rejected as well. Could something like this work for users with different levels of dexterity?
Creator here - yes, it's a mod of a Kensington SlimBlade Pro, mentioned on the site. Rotatrix is the hardware mod (added controller), firmware, and software stack that extracts 3DOF rotation and integrates into CAD and other apps. It's possible with firmware, but you need a trackball with dual optical sensors to do this (which very few have), and the system is patent pending. More on the architecture in the earlier Show HN: https://news.ycombinator.com/item?id=46990422
That's a strong claim for not looking into it at all.
From a brief glance at the white paper it looks like they are using TEE, which would mean that the root of trust is the hardware chip vendor (e.g. Intel). Then, it is possible for confidentiality guarantees to work if you can trust the vendor of the software that is running. That's the whole purpose of TEE.