This collection is intended for all who are the first users ZK-rollups.

Zero-knowledge rollups (ZK-rollups) are layer 2 scaling solutions that increase throughput on Ethereum Mainnet by moving computation and state-storage off-chain. ZK-rollups can process thousands of transactions in a batch and then only post some minimal summary data to Mainnet. This summary data defines the changes that should be made to the Ethereum state and some cryptographic proof that those changes are correct.

Zero-knowledge rollups (ZK-rollups) bundle (or 'roll up') transactions into batches that are executed off-chain. Off-chain computation reduces the amount of data that has to be posted to the blockchain. ZK-rollup operators submit a summary of the changes required to represent all the transactions in a batch rather than sending each transaction individually. They also produce validity proofs to prove the correctness of their changes. The validity proof demonstrates with cryptographic certainty that the proposed changes to Ethereum's state are truly the end-result of executing all the transactions in the batch.

The ZK-rollup's state is maintained by a smart contract deployed on the Ethereum network. To update this state, ZK-rollup nodes must submit a validity proof for verification. As mentioned, the validity proof is a cryptographic assurance that the state-change proposed by the rollup is really the result of executing the given batch of transactions. This means that ZK-rollups only need to provide validity proofs to finalize transactions on Ethereum instead of posting all transaction data on-chain like optimistic rollups.

There are no delays when moving funds from a ZK-rollup to Ethereum because exit transactions are executed once the ZK-rollup contract verifies the validity proof. Conversely, withdrawing funds from optimistic rollups is subject to a delay to allow anyone to challenge the exit transaction with a fraud proof.