Scroll is a zk-rollup built on top of Ethereum, which means it uses zero-knowledge proofs technology (specifically zk-SNARKs or zk-STARKs) to process transactions faster and cheaper than transactions processed directly on the Ethereum mainnet. This zk-rollups technology works by “roll-up” multiple transactions into a single transaction that is then verified and sent to the Ethereum mainnet. This allows more transactions to be processed at a lower cost and faster.