Zero-knowledge proof in cryptography (in short, ZKP) is encryption that allows one party (the prover) to prove to another party (the verifier) that they know a particular piece of information without revealing the information itself. In other words, the prover can demonstrate to the verifier that they know a secret without disclosing it.
One practical example of the use of zero-knowledge proof is online authentication. When a user logs into a website, the website must verify the user’s identity without seeing the user’s password. Zero-knowledge proof can be used to accomplish this.
The user can provide zero-knowledge proof that they know the password without revealing it to the website. This is done using a cryptographic algorithm that allows the user to prove knowledge of the password without revealing the password itself.
Figure: Zero-Knowledge proof demonstration
Zero-knowledge proof is achieved using mathematical techniques such as interactive proofs, where the prover and verifier engage in a back-and-forth exchange of messages, and cryptographic protocols such as zk-SNARKs (zero-knowledge succinct non-interactive argument of knowledge), which allow for very efficient verification of zero-knowledge proofs.
Zero-knowledge proof has good application in blockchain technology, specifically verifying transactions without revealing the transaction details. Zero-knowledge proofs can be used to verify that a transaction is valid without revealing the specific details of the transaction, such as the amount transferred or the parties’ identities. This ensures that the transaction is private and secure .
ZKP can also be used to ensure the integrity of blockchain data. For example, if a blockchain node wants to prove to another node that a certain block has not been modified, it can use ZKP to provide proof of integrity without revealing any other information about the block.
Another use case for ZKP in the blockchain is for confidential transactions, where the transaction amount is hidden from the public blockchain. This can be useful for maintaining financial privacy and preventing attackers from determining the balance of a particular address.
Zero-knowledge proof can greatly enhance blockchain technology’s privacy and security by allowing transactions to be validated without revealing sensitive information. However, the implementation of ZKC in blockchain technology is still in its early stages, and many technical and practical challenges must be overcome before it can be widely adopted.