zk-Rollup

A rollup that generates cryptographic validity proofs (ZK-SNARKs or ZK-STARKs) of every batch's correctness, posted to L1 for verification. Compared to optimistic rollups: shorter withdrawal times (hours vs 7 days), stronger cryptographic security, but higher proving costs. Production examples: zkSync Era, StarkNet, Polygon zkEVM, Linea, Scroll, Aztec. See also the topic on zk-SNARK vs zk-STARK vs PLONK.