Scroll is Ethereum's zero-knowledge scalability solution, offering lower costs, faster speeds, and unlimited scalability without compromising security or decentralization. It is byte-code compatible, making development on Scroll almost identical to development on Ethereum. From day one, Scroll has focused on community-driven development and is open-source. Through zkEVM, Scroll unleashes the full potential of Web3 while maintaining the same level of security as the Ethereum blockchain.
Scroll's On-Chain Metrics
As of the time of writing, the total value on the Scroll chain has reached $13,833,187, with 7,694 ETH on the chain. The current average block time on Scroll is 10.7 seconds, with a total block count exceeding 73,000. Scroll's mainnet was launched after over a year of testing, with over 55 million transactions completed on Alpha and Beta testnets and nearly 1 million batches confirmed on L1. The Beta testnet on Sepolia, the most recent one, connected over 900,000 wallet addresses and processed more than 6 million transactions within two months.
Regarding transaction data, Scroll has an average daily transaction count of 12,330, with a total of 271.7 million wallet addresses. To provide a comparison within the ZK Rollup track, leading projects such as zkSync Era had an average of 6.73 million transactions in the past month, Starknet recorded 3.53 million transactions in a week, Linea had 1.22 million transactions in a week, and Polygon zkEVM had fewer than 200,000 transactions in a week. This highlights Scroll's position in the ZK Rollup landscape, which is still subject to further observation and evaluation.
Technical Features of Scroll
Scroll is an EVM-equivalent zkRollup designed to extend Ethereum's capabilities. From a technical standpoint, Scroll is built on two core components. The core component is zkEVM, which ensures the correctness of L2 EVM execution.
The current Scroll architecture includes three fundamental infrastructure components:
Scroll Nodes: These build L2 blocks from user transactions, submit them to the Ethereum base layer, and facilitate message passing between L1 and L2.
Roller Network: This generates zkEVM validity proofs to confirm transaction correctness.
Rollup and Bridge Contracts: These ensure data availability for Scroll transactions, verify zkEVM validity proofs, and support asset transfers between Ethereum and Scroll.
(1) Scroll Nodes
Scroll nodes are the primary interface for applications and users to interact with Scroll. They consist of three modules: Sequencer, Coordinator, and Relayer.
The Sequencer provides a JSON-RPC interface and accepts L2 transactions. Every few seconds, it retrieves a batch of transactions from the L2 memory pool and executes them to create a new L2 block and a new state root. The Sequencer is deployed based on Go-Ethereum (Geth), a popular Ethereum node implementation. Forking Geth ensures the best compatibility and inherits time-tested security.
Once a new block is generated, the Coordinator is notified and receives the execution trace for that block from the Sequencer. It then assigns the execution trace to a randomly selected Roller from the roller pool to generate a proof.
The Relayer monitors the bridge and rollup contracts deployed on Ethereum and Scroll. It has two main responsibilities: monitoring rollup contracts to track L2 block states, including their data availability and validity proofs, and watching deposit and withdrawal events in bridge contracts deployed on Ethereum and Scroll, forwarding messages from one side to the other.
(2) Roller Network
The Roller network plays the role of a prover, responsible for generating validity proofs for zkRollup. Rollers should leverage accelerators like GPUs, FPGAs, and ASICs to reduce verification time and cost. The figure below shows how Rollers generate validity proofs for each block, involving the following steps:
- Rollers first convert the execution trace received from the Coordinator into circuit witnesses.
- They generate proofs for various zkEVM circuits.
- Finally, they aggregate proofs from multiple zkEVM circuits into a single block proof.
(3) Rollup and Bridge Contracts
Scroll is connected to the Ethereum base layer through Rollup and Bridge smart contracts, ensuring data availability for L2 transactions and allowing users to transfer assets and messages between L1 and L2.
Rollup contracts receive L2 state roots and blocks from the Sequencer. They store the state roots in Ethereum state and L2 block data as Ethereum call data. This ensures data availability for Scroll blocks and leverages Ethereum's security to enable indexers like the Scroll Relayer to reconstruct L2 blocks. Once a block proof establishing the L2 block's validity has been verified by the Rollup contract, the corresponding block is considered finalized on Scroll.
Bridge contracts deployed on Ethereum and Scroll support users in transferring arbitrary messages between L1 and L2. A trustless bridging protocol is built on top of this message-passing protocol, allowing for bi-directional bridging of ERC-20 assets between Ethereum and Scroll. To send messages or funds from Ethereum to Scroll, users invoke the sendMessage transaction on the bridge contract. The Relayer indexes this transaction on L1 and forwards it to the Sequencer for inclusion in L2 blocks. A similar process is used to send messages from Scroll back to Ethereum via the L2 bridge contract.
Scroll's Ecosystem
So far, over 100 projects have been deployed on the Scroll testnet, spanning from infrastructure to DeFi, games, and more.
Zada Finance
A decentralized exchange (DEX) built on Scroll that facilitates token exchanges between different Rollup networks.
SpaceFi
A DeFi hub focused on zkRollup networks, featuring a decentralized exchange, NFTs, liquidity mining, and a launchpad.
Espresso Systems
An Ethereum-based configurable asset privacy (CAPE) smart contract application developed by Espresso Systems. It aims to provide customizable privacy for transaction creators regarding the addresses and transaction amounts.
In Summary
Overall, Scroll aims to be an open protocol similar to Ethereum, maintaining openness at the core technology and infrastructure level, despite having a core development team. Scroll's goal is to drive the growth of the zkEVM ecosystem, achieve compatibility between the mainnet and zkEVM, and ultimately fulfill Ethereum Layer 1's objectives. Scroll has already launched its mainnet and achieved a new three-layer aggregation circuit prototype, providing strong technical support and infrastructure for its future development.
For more analysis, please follow Aibit's media account for real-time updates! This article is for reference only, does not represent any position, and is not intended as investment advice. Investment is risky, caution should be exercised.
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