zk-SNARK

A zk-SNARK (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) is a cryptographic proof that allows one party to prove they possess certain information to another party without revealing the actual data. "Succinct" means the proofs are small and quick to verify, while "non-interactive" means no back-and-forth communication is needed between prover and verifier. zk-SNARKs are used in privacy-focused cryptocurrencies like Zcash and increasingly in Layer-2 scaling solutions (zk-rollups) to bundle thousands of transactions into a single verifiable proof.