A professor I know once gave me the most beautiful example of a zero knowledge proof: she said “Imagine I want to prove to you that I can count the leaves on a tree, but I don’t want to reveal how I do it. I start by telling you there are e.g. 756,912 of them. Then I close my eyes and I let you remove as many as you want. We can keep going until you are convinced, and you still won’t know how I did it.”