# Zero Knowledge proofs of knowledge

Is there Zero Knowledge Proof of Knowledge protocol for Hash function? (If h(v)=w) without revealing v to the anyone can we prove that we know 'v')

• Every function in NP has zkp I think. – VS. Apr 21 '20 at 11:55

Yes. The simplest way to understand this is to understand the zero-knowledge proof that you know a 3-coloring of a graph. 3-coloring is NP-complete, so an arbitrary hash function $$h$$ and target value $$w$$ can be represented as a graph where knowing a 3-coloring for that graph is equivalent to knowing a $$v$$ such that $$h(v) = w$$.