π³Application-specific rollups & Virtual Machine
Last updated
Last updated
A rollup is a blockchain scalability solution that optimizes the processing of complex computations by moving them "off-chain." This means that these computations occur on a separate Layer 2 (L2) computing environment, distinct from the primary blockchain network (Layer 1 or L1, such as Ethereum). When implementing rollups, the primary function of the blockchain is limited to receiving and logging transactions. In rare cases where there are disputes over the outcomes of computations, the blockchain becomes involved in dispute resolution.
By offloading the blockchain from handling complex computations and by efficiently aggregating and compressing data, rollups have the potential to significantly increase a blockchain's transaction processing capacity, often by a factor of at least 40 times. Moreover, transactions conducted within rollups can incorporate much more intricate logic since applications operating within a rollup environment can perform nearly any computation and leverage more powerful virtual machines (VMs) that run on the Layer 2 infrastructure. This approach contributes to improved scalability, reduced transaction fees, and enhanced flexibility for blockchain networks.
Users engage with a rollup by initiating transactions on the underlying layer (L1). They transmit messages (inputs) to the on-chain smart contracts of the rollup, specifying a computation to be carried out, which subsequently advances the state of the computing environment on L2. Parties interested in the process operate an off-chain component, known as an L2 node, which monitors the blockchain for these inputs, comprehends them, and executes the state updates.
Periodically, the state of the computing environment is recorded on-chain. At this juncture, the state becomes finalized and can be acknowledged by any smart contract on L1. It is imperative to ensure the security of this operation, necessitating the L2 node to provide a means of verifying the new state to the underlying layer.
In validity proof systems, each state update is accompanied by an off-chain cryptographic proof, certifying its legitimacy. The update is considered valid only if the proof successfully passes on-chain verification. Zero-knowledge proofs are commonly employed for this purpose, hence the frequent reference to such rollup solutions as "ZK Rollups." Validity proofs offer a significant advantage of immediate finalityβonce a state update is recorded on-chain, it can be completely relied upon and acted upon without delay.
