I need to read up on the fundamentals of zero knowledge proofs. There are lots of online articles that try illustrate with "easy" examples what they are, but the explanations are often barely coherent. There are definitions like "a method by which one party can prove to another party that a statement is true, without revealing any information apart from the fact that this specific statement is true." But then if you look at the examples, it seems like there is tons of additional information being revealed to the other party. It feels like what they mean is "a method by which one party can prove to another party that a statement is true without revealing *certain specified* other kinds of information that one wants to keep secret to the other party." That's of course fine for what it is, but then they probably shouldn't be called "zero knowledge" but instead "limited knowledge" proofs or something like that. But I need to read up on them before I say too many ill-informed things.