Zero-Knowledge Proof

CORE DEFINITION

In cryptography, a zero-knowledge proof or zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that a given statement is true, without conveying any information apart from the fact that the statement is indeed true. Therefore, it can be understood as a 'zero-leakage proof'. For example, to prove to someone that you possess certain information, you could directly reveal the information, but that would also disclose the details. The essence of a zero-knowledge proof is how to prove that you possess the information without revealing its content. This is also the difficulty of zero-knowledge proofs. If proving the statement requires knowledge of a secret, then the verifier, having only witnessed the proof without learning the secret, cannot prove the statement to a third party (i.e., mere transcription is insufficient). The statement to be proven must include the prover's claim that they know the secret, but the secret itself must not be conveyed during the process. Otherwise, at the end of the protocol, the verifier would have been given additional information about the statement. This type of 'zero-knowledge proof of knowledge' is a special case of zero-knowledge proofs, where the statement to be proven is only that 'the prover knows something'.