The problem is not cryptography, the problem is copyright.
Nouveau could in theory upload the signed firmware blob from a legitimate driver to the GPU and build an interface to communicate with it. The problem is, the legitimate driver package prohibits any kind of modification outside the intended purpose, which means it's questionable if building and redistributing a tool to extract the firmware blob out of a driver package is legal, and it's certainly not legal to redistribute that extracted blob.
Here in Europe, at least the building and distribution of the tool as well as the act of the user to download the legitimate driver package, extract and use the blob should be legal, but that doesn't help if the developers of the project are outside of the EU :(
1. Only applicable to an "approved use" of the hardware.
Try buying any of those in Brazil or non US/UK/EU countries and you’re going to have tons of fun with import taxes and shipping.
Suddenly, a cheap device costs more than a flagship iPhone or android with none of their benefits except the intangible freedom.
One of the best purchases I ever made was a le eco le pro 3 phone once the company went bankrupt for half the retail price 5 years ago. Bought it because it already had LineageOS support. Today it runs Lineage OS 18.1 (android 11) like a champ, it can be make to run bank apps (passing safetynet) if I want to. Still lineage OS is not a silver bullet you either need to get lucky and pick a phone with a big enough following that volunteer devs will support or scout XDA threads in order to identify those phones before purchasing.
Videos are easy to though.