What is ZKP

Zero-Knowledge Proof (ZKP) is a cryptographic protocol where one party, called the prover, convinces another party, called the verifier, that a statement is true without revealing any information beyond the validity of the statement itself. The key idea is that the prover can convince the verifier of the truth of a statement without disclosing any additional information that could compromise privacy or security.

One example of a zero-knowledge proof is the "Ali Baba's Cave" protocol, which illustrates the concept of proving knowledge of a secret without revealing the secret itself. Here's how it works:

1. Setup: Assume there's a cave with a secret entrance that only opens when a secret phrase is spoken. Alice wants to prove to Bob that she knows the secret phrase without revealing the phrase itself.
2. Interaction:
   • Alice and Bob agree on a protocol where Alice will prove her knowledge of the secret without disclosing it.
   • Bob stays outside the cave while Alice goes inside. Alice randomly chooses one of two paths in the cave: the left path or the right path.
   • Alice exits the cave and meets Bob. Bob doesn't know which path Alice took.
   • Bob challenges Alice to prove that she knows the secret phrase without revealing it. He does this by choosing a path (either left or right) and asking Alice to re-enter the cave through that path.
   • If Alice indeed knows the secret, she can enter the correct path (the one she originally chose) as requested by Bob. This action convinces Bob that Alice knows the secret without revealing which path she originally took.

3. Conclusion:

• By repeating this process multiple times with different challenges, Bob becomes increasingly convinced that Alice knows the secret phrase.
• However, at no point does Alice need to reveal the secret phrase itself. Bob gains confidence in Alice's knowledge without learning anything about the secret.

This example illustrates the idea behind zero-knowledge proofs, where a prover can convince a verifier of a statement's truth without revealing the underlying information that supports the statement.