What is a zero-knowledge proof?

A zero-knowledge proof is a cryptographic method for establishing a claim without revealing the secret information that supports it. The claim and some inputs may be public; the proof protects the information it is designed to keep private.

The prover demonstrates that a condition holds. The verifier checks the proof instead of receiving the secret. The assurance depends on the protocol's rules and assumptions; it does not automatically establish that every statement supplied to a computer is true in the outside world.

Example

Imagine someone knows a valid solution to a publicly available Sudoku puzzle. A suitable proof system can establish that the rows, columns and boxes satisfy the puzzle's rules without revealing the solution's digits. The verifier can check the claim without learning the solution. The example illustrates the method's purpose; it is not a report of an application we tested.

The ZK rollup label does not mean every transaction is private. A validity proof can establish that a blockchain state transition follows its rules while addresses and transaction data remain public. Privacy requires a separate check of which information the system actually hides.

The rollup security guide examines how proof mechanisms affect network selection alongside data availability and exit conditions.