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Guide to AltLayer

August 13, 2024

Rollups everywhere

It started with the rollup-centric roadmap — transaction execution is abstracted to another layer where it is done faster and cheaper, and eventually it is settled back onto Ethereum. Now, we have different rollups (with a lot of TVL) handling a significant transaction load for Ethereum. 

More recently, we’ve begun introducing rollup SDKs and rollup-as-a-service (RaaS) providers that make building and deploying rollups much more simple. In fact, it’s now as easy as building and deploying smart contracts.

With rollups omnipresent and easy to deploy, they need supporting services and tools to achieve maximum functionality. The services they need vary but include fast finalization, external data availability services, fast bridging, decentralized sequencers, and watcher networks. 

The introduction of such supporting services feeds into the ethos of modularity, allowing specialization of certain functionalities, while being used to foster an overall system of interconnected parts.

How does EigenLayer fit into all of this? EigenLayer lets anyone build many of the above functionalities leveraging Ethereum’s economic security and decentralized validator set. And thus the restaked rollup was born.

Restaked rollups

Restaked rollups combine the ease of deploying rollups with EigenLayer’s restaking to bootstrap network security and decentralization. As a result, it is possible to build some of the ancillary rollup services mentioned in the previous section. 

AltLayer introduced the concept of restaked rollups, consisting of three vertically integrated actively validated services (AVS) created on demand for any rollup spun up from an underlying rollup stack.

These are AVS are:

  • VITAL: An AVS for decentralized verification of a rollup’s state

  • MACH: An AVS for fast finality

  • SQUAD: An AVS for decentralized sequencing

Built on top of these AVS is AltLayer’s RaaS launchpad, allowing developers to efficiently deploy customized rollups. Let’s get into each of these AVS in more detail.

VITAL

VITAL functions as a verification layer for rollups. This is a network of operators that verifies all new states proposed by SQUAD operators. It can challenge those operators in the event of an invalid state transition. 

Source: AltLayer Docs: VITAL

MACH

MACH functions as a fast finality layer for rollups. Finality refers to a rollup’s ability to guarantee its post-execution state will be settled on Ethereum. For example, Optimistic rollups have a finalization window of about 7 days. We know this as the “challenge period” for anyone to be able to submit a fault proof to challenge the validity of the transactions. MACH also serves as a bridging hub to coordinate AltLayer rollups. 

In order to guarantee fast finality, MACH needs to verify the validity of a rollup state so it provides three validity modes:

Pessimistic Mode

Each transaction is considered invalid by default and will need to be re-executed.

Source: AltLayer Docs: MACH

Optimistic Modes

Optimistic Mode (I): This is how we know current optimistic rollups to work. Transactions are asserted as valid unless otherwise challenged.

Source: AltLayer Docs: MACH

Optimistic Mode (II): Optimistic mode but with on-demand ZK fault proofs. The ZK proof is only generated if there is a challenge.

Source: AltLayer Docs: MACH

Validity Proof Mode

The MACH network acts as a decentralized verifier network for validity proofs. The validity proof will be generated along with the set of transactions and resulting state. MACH will reach consensus on the validity of the proof.

Source: AltLayer Docs: MACH

SQUAD

Sequencers in any rollup are responsible for aggregating, ordering, and batching transactions and sending them back to the L1. Most rollups today operate on one sequencer which can affect real time censorship resistance and liveness guarantees. 

Rollups created by AltLayer’s launchpad can specify the number of sequencers, the minimum amount of economic security, and a list of tokens they wish to have with their rollup (i.e., where the economic collateral can come from). In this scenario, EigenLayer operators run the sequencers. 

Source: AltLayer Docs: SQUAD

Conclusion

With its comprehensive suite of AVS — VITAL, MACH, and SQUAD — AltLayer offers a unique solution to enhance the functionality and security of rollups in the blockchain space. VITAL ensures decentralized verification of rollup states, MACH provides fast finality and bridging capabilities, and SQUAD delivers decentralized sequencing. Together, these services form a robust framework that supports the rapid deployment and efficient operation of rollups.

As one of the operators supporting AltLayer MACH through our participation in the EigenLayer protocol, Coinbase is committed to advancing Ethereum's capabilities in an open and sustainable manner.

To learn how to delegate to Coinbase’s operator, please refer to our delegation guide or contact us today to get started.

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