GlossaryAdvanced
ZK Rollup
A rollup design that submits a cryptographic validity proof with every batch of transactions, checked by the base chain before finalizing.
A ZK (zero-knowledge) rollup is a type of rollup that submits a cryptographic validity proof — generally a zk-SNARK or zk-STARK — alongside every batch of transactions, which the base chain verifies before accepting the batch as final.
Because the base chain checks a validity proof directly rather than relying on a challenge-and-dispute window, a ZK rollup generally doesn't need the same withdrawal delay an optimistic rollup does, at the cost of a more computationally demanding proof-generation process.
Examples
- A ZK rollup's validity proof lets the base chain confirm an entire batch of transactions is correct without re-executing each one individually.
- ZK rollups generally offer faster withdrawals back to the base chain than optimistic rollups, since there's no fraud-proof challenge window to wait out.