Zero-Knowledge Proof Meaning

Apr 5, 2023 | Updated Jul 18, 2023

A Zero-knowledge proof (ZKP) is a type of secure verification that allows one party to prove the validity of something, without having to reveal any personal details, passwords, or statements. In the context of blockchain it is a cryptographic method that allows for the verification of a data without the need to reveal any of the underlying data.

What Is Zero-Knowledge Proof?

Zero-knowledge proof (ZKP) is an authentication technique that takes place between a prover (the party proving the claim) and a verifier (the party validating the statement). ZKP allows users to prove that they have certain information or own assets without having to reveal what the information or assets actually are. This can be instrumental in applications like secure voting systems, identity verification, digital assets transfer, etc., where maintaining information privacy is important.

For example, it can be used to enable secure and private sharing of medical data between healthcare providers and patients. This could allow patients to control who has access to their data while still allowing doctors and researchers to access important medical information for research and treatment purposes.

ZKP can also be used in supply chain management to ensure the authenticity and integrity of products. Companies can prove that a product is genuine without revealing any sensitive information about the product or its production process. This can help prevent counterfeiting and ensure that customers are getting authentic products.

In the context of blockchain, privacy-focused cryptocurrencies use ZKP to prove a transaction is valid without disclosing the transaction details, such as the identities of the sender and recipient and the amount involved.

To validate something using a ZKP, the prover needs to demonstrate “completeness”, and the verifier needs to ascertain the statement’s “soundness”. Completeness means that the statement is true to a high degree of likely correctness. Soundness is when the verifier can confidently agree that the prover has knowledge of the information.

ZKPs can reach the required levels of completeness and soundness through two systems: interactive and non-interactive.

What are the Characteristics of Zero-Knowledge Proof?

Zero Knowledge Proofs are either interactive or non-interactive. With an interactive ZKP, the prover and the verifier must communicate with each other to prove their statements, making it barely scalable. In non-interactive ZKP, the parties don’t need to communicate in order to complete a transaction, but rather via complex cryptographic hashing.

Modern cryptographers find zero-knowledge protocol essential in providing better security and privacy and accuracy in systems. Software running on ZKP enables users and businesses to keep their information private so that they only share the necessary data with a third party.

A popular real-world utility of ZKP is in cryptocurrencies and blockchain networks, where zero-knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARK) is used in privacy-oriented crypto like Monero and Zcash. On these networks, it can be used for privacy-enabled payments, authentication, verifiable computation, and identity protection.