Today, with the increasing development of blockchain technology, how to improve the finality of transactions, especially in Ethereum's Rollup solution, has become an important research topic. To solve the slow finality problem of Rollup, we propose MACH: a layer that provides fast finality for Ethereum Rollup. MACH has the following key features:
Quickly confirm rollup transactions
Cryptoeconomic security against any malicious cyber actor
Support ZK and optimistic rollup
General enough to support different proof systems and runtimes
How MACH works: In order to ensure finality, MACH as a network needs to verify the validity of the Rollup state to ensure that the Rollup operator follows the state transition function. To this end, MACH supports three status validity modes.
pessimistic mode
In pessimistic mode, each transaction is considered invalid by default and therefore needs to be re-executed. This means that the Rollup operator sends transaction data directly to the MACH network, which then re-executes the transaction and reaches consensus on the validity of the state proposed by the Rollup operator.
While this mode of operation is the simplest of all, its main disadvantage is that it is not very efficient, since MACH actually runs as a full node network for Rollup. This results in high demands on the nodes. Future work will be devoted to building stateless clients to reduce the state required to operate Rollup nodes.
optimistic mode
In optimistic mode, the rollup operator declares a state claim on MACH indicating that the execution of a specific block of transactions resulted in a specific state commitment. Any node in the MACH network can challenge the claim and invalidate the new state by engaging in a binary agreement with the Rollup operator.
This setup assumes that there is at least one honest node in the MACH network and that the network nodes are mostly in observation mode. It is worth noting that the bipartite protocol will only be triggered when the challenger considers the state commitment to be invalid. Additionally, it is possible to replace the bipartite protocol with ZK proofs that are generated on demand, so that proofs are only generated when a challenge occurs.
Validity proof model
In validity proof mode, the MACH network acts as a decentralized verification network for validity proofs. A rollup operator (such as the sequencer) will submit a new set of transactions, resulting states, and their validity proofs to MACH. The MACH network will then verify and reach consensus on the validity of the proof.
Although validity proofs are used explicitly, this pattern also works well with optimistic rollups. In an optimistic rollup, any designated prover (outside of MACH) with the right incentives can generate a validity proof and submit it to the MACH network, which in turn verifies and reaches consensus on the validity of the proof. It is important to note that with ZK Rollup, provers can generate and submit proofs more frequently than on Ethereum, so speeding up finality is critical.
Advantages and future prospects of MACH
The design of MACH not only improves the finality of Rollup transactions, but also ensures the security of the network. By supporting multiple state validity modes, MACH can flexibly respond to different usage scenarios and needs. In addition, MACH's encryption economic model enables it to resist potential malicious attacks and ensure the stability of the network.
In the future, MACH can be further optimized, such as by introducing stateless clients to reduce the resource requirements of nodes, thereby attracting more participants to join the network. At the same time, as blockchain technology continues to evolve, MACH will continue to adapt to new challenges and opportunities and continue to promote the healthy development of the Ethereum ecosystem.
in conclusion
In general, MACH, as the fast finality layer of Ethereum Rollup, provides a strong guarantee for the confirmation speed and security of blockchain transactions with its innovative design and diverse validity modes. With the continuous advancement of blockchain technology, MACH will play an increasingly important role in future networks, helping to build a more efficient and secure decentralized financial ecosystem.
Through an in-depth understanding of MACH, we can see that blockchain technology is not only constantly developing, but also constantly meeting the growing needs of users. We hope that more innovative solutions will emerge in the future, bringing more possibilities to blockchain application scenarios.