The closest I got was "usually governments and law makers have been tasked with creating money and defining its value and how it is used, but bitcoin has a predefined set of rules that can only be changed by all its users in every country around the world..." Anything more than that, and I feel I would have got the deer-in-the-headlights stare. I think that's probably a topic for grades 9-12.

Now that I have a basic syllabus, I plan on going over it in more detail with a teacher from each grade and developing a grade specific version.