Some ZK way to prove that a piece of data was derived from some source, for example, proving a human fingerprint is unique identifying biometric data without showing the data itself or the person it is from and with no trusted authority.
Just thinking out loud here: I think it would require trusted sources (not necessarily a centralized authority) that have validate it and that you trust.
You can prove two balls are different colors to a colorblind person by having them show you two balls of X color and proving to them that you can differentiate them (watered down example), but it requires validated externalities (ex, you can see colors they can’t).
Defining the external validators is the hard part.
If it did require a trusted source, do you think there would be a way for said source to 1) involve no human administration, 2) behave deterministically and 3) be resistant to attacks that could break either of the above 2? That would also solve the problem.
