Zero-knowledge proof
In general, a ZK/validity proof is a cryptographic method of transaction verification in which a prover develops a proof for specific information, and a verifier validates the proof. A ZKP allows someone to publicly verify that they possess specific information without revealing the specifics or details of that information. As a result, Zero-Knowledge cryptographic proofs provide phenomenal privacy features as well as reduce the computing and storage resources for validating the block by reducing the amount of data held in a transaction (since zero knowledge of the entire data is needed).