I think that you are working from the right premise, but coming to the wrong conclusion. A system that permanently records a credential granted from another user cannot maintain privacy. It is not so much that a positive mark on your record is a problem, it is that education requires failure and the tracking of negatives. Tracking those negatives is absolutely necessary for a person to chart their course. Sharing those negatives is absolutely necessary to match a user to new opportunities. Having those negatives recorded outside of the users control is an absolute no no.
When you communicate your learning outside of the context of learning it needs to be in a way that allows you to highlight the competitive aspects of your record. Not in a way that penalizes you for mistakes along the way.
So BitofTrust? A form of points that are recording in blockchain. But what are they? If I answer 100 questions about PB&J do I get hundred Bitsotrust? What is the relative difficulty of those questions? What are the questions? What was my answer? Who validated the answer?
It sounds like another abstraction in a world of hard data. And another way for people to exert control over others by dictating arbitrary ways to confer credibility.
I think we need to find more ways to remove opinion from education. And add more hard science validation of learning.
This proposal feels like a way to create an highly biased record of learning in a very permanent way.
Something that could be disruptive but not transformative. It would just change who the educational masters are, not make conferring credibility into a true meritocracy.