I think that is an acceptable understanding. In a more formal setting, we talk about witnesses [1]. In effect, there is some piece of "knowledge" that will conv

I think that is an acceptable understanding. In a more formal setting, we talk about witnesses [1]. In effect, there is some piece of "knowledge" that will convince someone that you can solve something. With Waldo [2], that would be the actual location (x-y coordinates) of Waldo. If I want to convince you that I know where Waldo is, I can just give you the X-Y coordinates of his location. This has the unfortunate side effect of giving _you_ the ability to convince people you know this knowledge (you now know where Waldo is) - we have revealed the witness to you. In a general sense, a zero knowledge proof is a class of protocols where you convince another party that you know the witness of a problem without having to reveal it to them (they receive zero knowledge about the witness). [1] https://en.wikipedia.org/wiki/Witness_(mathematics) https://en.wikipedia.org/wiki/Witness_(mathematics) [2] http://www.anagram.com/jcrap/Volume_0_1/crv0n1-3.pdf http://www.anagram.com/jcrap/Volume_0_1/crv0n1-3.pdf