ZK proof (Zero-Knowledge Proof)

A cryptographic proof that a statement is true without revealing why it's true.

A zero-knowledge proof lets a prover convince a verifier that they know some information — or that a computation produced a specific result — without revealing the information itself. The math has been studied since the 1980s but only became practical for blockchain applications in the late 2010s.

ZK proofs are the core technology behind ZK rollups (proving an L2 state transition is valid without re-executing it on L1), privacy protocols (proving you own funds without revealing which funds), and identity primitives (proving you're a verified human without revealing your identity). The trade-off is heavy computation to generate proofs versus fast verification.