What is a zero-knowledge proof in cryptography?

A zero-knowledge proof is a cryptographic method that enables one party to prove to another that they know a value or can perform a specific computation, without revealing any actual information about that value or computation itself. This is particularly useful in enhancing privacy and security in various applications, including authentication, identity verification, and secure transactions.

In the context of a blockchain or cryptographic systems, zero-knowledge proofs allow for the verification of credentials or the validity of transactions without exposing the underlying data. This means a user can prove they possess certain information without needing to disclose that information, thereby maintaining confidentiality and security.

The other options describe different functionalities and techniques in the blockchain ecosystem, but they do not accurately capture the essence of zero-knowledge proofs. Encryption of transactions pertains to securing data, data compression involves reducing the size of data for storage or transmission, and consensus protocols are mechanisms that ensure agreement among nodes in a distributed network on the state of the blockchain. None of these options align with the unique capability of zero-knowledge proofs to validate information without revealing the specifics of that information.