- rollups move computation (and state storage) off-chain, but keep some data per tx on-chain, using compression tricks to replace data with computation wherever possible (but scalability is still limited by the data bandwidth of the underlying blockchain).
- an on-chain smart contract maintains a state root (the merkle root) of the state of the rollup.
- anyone can publish a batch (collection of txs, compressed to form the previous state root and the new state root).
- the contract checks that the previous state root in the batch matches the current state root - if not, it switches the state root to the new state root.
- for depositing and withdrawing, txs can have input or output outside the rollup state (processed within the batches).
- optimistic (fraud proof) or zk (validity proof) rollups are solutions to know that the post-state roots in the batches are correct.
- started rollups
- largest TVL
- rollup from optimism collective, with a rich ecosystem of l2
- tool to create l2 part of the superchain
- l2 from bitdao
- the leading zk-rollup and a zkevm (zk-rollups that use ethereum virtual machine to execute transactions are called zkevms)
- the only zkevm that supports native account abstraction in the consensus layer of the chain
- zk-rollups from starkware
- not a zkevm
- used the cairo language
- has recently open-souced their STARK prover
- part of polygon 2.0, an ecosystem of zk-rollups
- converting polygon pos into a zk-validum
- has their prover open-sourced
- another recent zkevm from consensys
