Data availability

Data availability is the ability for network participants to access transaction data needed to verify a blockchain or scaling system. A blockchain cannot be properly checked if the data behind its transactions is hidden or not made accessible. In Layer 2 systems, data availability is particularly important because transactions tend to be processed away from the main blockchain. However, there still needs to be enough published data for users or validators to confirm the results. Data availability affects security, transparency, and the ability to reconstruct the state of a network.

A rollup may process many transactions off Ethereum but publish transaction data back to Ethereum or a data availability layer so others can verify the rollup’s state.