GlossaryAdvanced
Fraud Proof
Evidence submitted during an optimistic rollup's challenge window demonstrating that a submitted batch of transactions was invalid.
A fraud proof is evidence submitted during an optimistic rollup's challenge window, demonstrating that a specific batch of transactions the rollup submitted to the base chain was actually invalid.
Anyone monitoring the rollup can generally submit one; if accepted, it typically reverses the disputed batch and penalizes whoever submitted it — the mechanism that lets an optimistic rollup assume validity by default while still being held accountable.
Examples
- A fraud proof must generally be submitted within an optimistic rollup's challenge window, or the disputed batch becomes final regardless of whether it was actually correct.
- The possibility of a fraud proof being submitted is what disincentivizes an optimistic rollup's operators from submitting invalid transaction batches in the first place.