Movement: A Network of High-Throughput Fast-Finality Move-based Rollups Secured by Ethereum Version 0.2.3 Movement Labs September 5, 2024 Abstract. We introduce Movement, a secure and scalable network of Move-based rollups secured by Ethereum, addressing the need for safer execution environments. At its core is the Movement Stack, a modular framework for creating highly customizable Move Rollups. The Movement Rollup, our flagship general-purpose L2 Move Rollup, showcases the capabilities of the Movement Stack: 1. Move Executor: A high-throughput execution layer with the MoveVM, parallel execution and EVM compatibility for seamless integration with existing applications. 2. A novel fast-finality settlement mechanism, achieving confirmation times in seconds, by leveraging economic security from a network of validators while retaining Ethereum's security. 3. Modularity: Movement Stack integrates with multiple DA services and sequencers. Developers can also opt for validity or optimistic rollup configurations to achieve traditional Ethereum security guar- antees. We also introduce the Move Arena, our sophisticated infrastructure that integrates Movement with our set of in-house services and that enables an ecosystem of next-generation interoperable rollups. As part of Move Arena, rollups benefit from M1 , our decentralized shared sequencer net- work, which enables seamless cross-rollup interoperability , enhances cen- sorship resistance, and eliminates single points of failure. M1 is secured through our multi-staking mechanism, which pools eco- nomic security across Movement and beyond, minimizes the infrastruc- ture requirements and maximises the sovereignty of each Move Rollup. jacks[c]cvclocs@eocm0class@eocm0s@eoccm0s@eoccm0s@eoccms@eoccasacyaclw@eoccanamon@eoccase@eoccmaceacc instatus well wit wit instal wit the state of ware to seek and ware to seek and ware and ware and ware to seek and ware to seek and ware to seek as wel

Glossary

1
Objectives & Motivation
Blockchain technology provides a decentralized ledger where participants can transact without relying on a central authority. The Ethereum Network [5] was the first to propose a versatile world computer [12], with programmable trans- actions called smart contracts , and the ability to implement arbitrary business logic that go beyond simple currency or assets' transfers (pioneered by the Bit- coin network [11]). Wide adoption of the Ethereum-based technology is s still hindered 1 by several limitations, such as slow transaction confirmations (also referred to as finality time or latency ), low throughput (expressed in transactions per second, TPS ), and widespread security vulnerabilities in decentralised Applications (dApps). Ethereum mainnet, with its unmatched level of Total Value Locked (TVL), offers the highest level of crypto-economic security, which cre- ates an unrivaled incentive to capitalise on its best-in-class security guarantees. Several solutions have been proposed to address the above limitations of the Ethereum network. The most popular ones being rollups, which are Layer 2 (L2) solutions that bundle multiple L2-transactions into a single Layer 1 (L1) transaction. Note that we use L1 and Ethereum interchangeably in this paper, however, this is applicable to other L1s as well as L2s. Rollups settle transactions on the Ethereum mainnet, thereby inheriting its high level security. Rollups have been successful in addressing some of the scalability limitations of Ethereum, but they have not been able to fully address the security vulnerabilities of dApps, nor the latency issues. Some of the original design choices of Ethereum, inherited by Ethereum rollups, have made it a very complex infrastructure, making it difficult to address the current limitations. For example, the EVM is not designed to prevent secu- rity vulnerabilities 2 , unintended assets's duplications or re-entrancy attacks [7,8]. The global storage model of the EVM itself makes it hard to parallelise the exe- cution of transactions, which severely limits the scalability of the network. How- ever, the design choices and limitations of the Ethereum network offer a good opportunity to reflect on the current technology and see how to improve it. Recently new paradigms have emerged for the execution layer, offering new execution environment and programming languages. An example for the latter is Move, originally developed at Facebook (Diem/Libra project), a next generation highly secure and efficient Web3 development platform, providing principled solutions to security vulnerabilities and scalability. It empowers Web3 developers with modern tools to tackle the challenges of deploying reliable, cost-effective w and efficient dApps. Move and the MoveVM are used in L1 chains, such as Aptos [2], Sui [4,13], and 0L [1,10] and has demonstrated very promising results in terms of security, low latency (sub second finality) and throughput (sustained reported throughput of 30k TPS and 160k theoretical, compared to a typical 20 TPS for Ethereum). The Move language [3] proposes a new approach to Web3 develop- ment and was designed to address the current blockchain technology limitations. Move introduces a novel programming paradigm known as resource-oriented programming , enabling parallel execution of transac- tions in the MoveVM, together with strong security guarantees using formal verification. One of the main challenges for the Move community is to build an ecosystem that is crypto-economically secure, but for the time being, the L1 chains Aptos, Sui and 0L have not attained the TVL 3 , liquidity and developer activity levels 4 of Ethereum yet. This is a compelling opportunity for our Move community to bring together the highly crypto-economically secure Ethereum platform and Move/MoveVM, the most technologically advanced Web3 development platform. Our proposal is to build a network of interoperable chains to bridge the gap between two ecosystems, Move and Ethereum, where the most advanced Web3 technology meets the most crypto-economically secure L1 chain. Our contribution. In Section 2, we introduce Movement Rollup, a general purpose Move-based rollup. The Movement Rollup architecture is extracted from the more general Move Rollup blueprint framework, described in Section 3, which is shared by all Move-based rollups in our network. Section 4 describes our novel fast-finality settlement mechanism. In Section 5, we introduce Move Arena the network of Move-based chains, and also, M1 , the shared sequencer that enables cross-chain interoperability.
2
The Movement Rollup
Movement Rollup is Movement Labs' general-purpose rollup (Figure 1). It is the first Ethereum L2 that will integrate Celestia for Data Availability, decen- tralized shared sequencing, fast finality through attestations, and the Move Vir- tual Machine ( MoveVM ) for execution, which offers unparalleled transaction throughput. This integration will allow developers to create high-performance, consumer-focused applications with minimal resource expenditure. 2.1
Original components
We develop three original components, that we capitalise on in the Movement Rollup. 1. The Move Executor (Section 3.2), which supports both MoveVM and EVM transactions, enabling Web3 developers to deploy smart contracts in Move and EVM bytecode on a single network. 2. A Fast Settlement module (Section 4) which connects to an validators net- work , facilitating fast settlement finality when compared to optimistic and validity settlement mechanisms. 3. A decentralized shared sequencer module, M1 (Section 5) which ensures cus- tomizable transactions ordering, with templates from a set of approaches, such as fair transaction ordering for mitigation of front-running attacks and enhancement of censorship resistance. First, Movement Rollup supports both MoveVM and EVM transactions. This is a unique feature of our architecture, as most rollups only support one type of transactions. This feature is critical to allow Web3 developers to onboard the Movement Rollup quickly. It is also a significant advantage for the Move Arena (Section 5) as it allows developers to leverage the existing EVM dApps and extend them benefiting from the advanced features of the Move platform. For instance, standard EVM contracts like ERC-20 can be deployed on Movement Rollup and new and secure Move dApps can be developed to interoperate with them. The Move Executor supports both MoveVM and EVM transactions, allowing Web3 developers to deploy smart contracts in both Move and EVM bytecode on the same network. It provides a unique infrastruc- ture where Web3 developers can migrate or extend their existing EVM dApps with the more secure and efficient Move framework. Second, we introduce a fast settlement mechanism (Section 4), an alternative settlement mechanism to validity and optimistic rollups. Fast-Finality Settle- ment relies on a set of validators who stake native tokens. The validators have to confirm the correctness of the new L2 state by forming a majority (e.g., 2/3 of the total stakes) to validate the new state. The fast settlement mechanism offers fast finality and also contributes to increasing the utility of the Movement Rollup native token. Third, by utilizing the M1 sequencer, Movement Rollup builds on an alterna- tive to sequencing marketplaces, such as Espresso, Astria, or L1-based sequenc- ing. This is a deliberate choice to ensure the sovereignty of Movement Rollup (and the Move Rollup network more generally) and provide a fast, customizable and verifiable ordering of transactions. Another consideration is the complexity of (decentralized) shared sequenc- ing marketplaces especially when it comes to distributing rewards and penalties, which are hard problems currently lacking good solutions. A sovereign sequencer module offers a solution where fees can be collected by the L2 rather by an exter- nal component (marketplace), thus positively impacting the utility of the native token of the L2. Shared sequencing aims to provide some level of interoperability between different rollups and it is discussed in Section 5.2. The M1 sequencer provides a sovereign, fast, customizable and censor- ship resistant ordering of transactions, enabling interoperability and increasing the utility of the native token of the Movement Rollup.
2.2
Original frameworks
We develop two original frameworks, that we capitalise on in Movement Rollup. 1. The Movement Stack (Section 3.3) which enables to create customizable rollups, with the Move Executor at the heart. 2. The Move Arena (Section 5) which provides a framework to deploy and join the Move rollups network. A Move Rollup can be configured to connect to the various components of the Move Arena, such as fast settlement or the M1. This permits it t to tap into Move Arena's benefits, which are interoperability with other Move Rollups, fast-finality and more.
3
The Move Rollup framework and the MoveVM
We introduce the Move Rollup (Figure 2), our general-purpose Move-based rollup schema for Ethereum-secured rollups. Move Rolup is a modular arhi- tecture where components can be configured to fulfill customers' needs with the most suitable, cost-efficient and performant components. In Move Rollup, we offer fraud proof, ZK-proof, and a new fast finality mech- anism (Section 4), where a network of validators who have staked native tokens, validate the correctness of the new L2 state and the availability of the data, and provide ultra-fast reliable finality with high-economic security. We show a categorization of Move Rollup configurations in Figure 5 and provide examples in Table 1.
3.1
Architecture of Move Rollup
Move Rollup is a generic architecture for creating Move-based rollups that are rollups using the Move Executor (Section 3.2, Figure 2, page 8). The Move Rollup generic architecture has a set of core components: ● Executor to process transactions and generate new L2-blocks. ● Bridge contracts on L1 for asset deposits and withdrawals between L1 and the rollup. 7 ● Connection to a Sequencer to order transactions. ● Connection to a Data Availability (DA) service to ensure transaction data accessibility to the settlement mechanism. ● Connection to a Settlement Mechanism: to verify transaction execution cor- rectness. Move Rollup can be used to create Move-based rollups, for instance the Move- ment Rollup (Section 2) is an instance of this generic architecture. The lifecycle of a transaction within a Move Rollup is as follows: 1. A transaction tx is submitted to the mempool (client, top of Figure 2). 2. The sequencer extracts a batch b of transactions from the mempool, including tx, and orders them. The sequencer publishes the transactions data of b to the DA service (L1 or an alternative DA). 3. The executor processes the transactions. This results in a new L2 state (and a short commitment of it, know as a state root s) that is also published to L1 in the bridge contract. 4. The settlement of the transaction tx happens when the L1 validating bridge contract verifies or approves the new state. This can be done with ZK-proofs, by passing the challenge period successfully in optimistic rollups, or when the quorum certificate is validated in Fast-Finality Settlement.
3.2
The Move Executor
The execution layer of all Move Rollups, such as Movement Rollup, is the MoveVM. The Movement Stack provides an execution module, Move Execu- tor, that can execute MoveVM bytecode and EVM bytecode. This module is at the heart of our architecture and not configurable. The Move Executor module supports the execution of both MoveVM and EVM bytecode on the same chain.
8
Figure 3 gives a high-level view of the Move Executor module. Transactions are triaged from the mempool according to their types, Move or EVM. A cor- responding VM (MoveVM or Geth) executes a transaction. In MoveVM this results in a change set that is later applied to the global storage. In Geth a transaction can be executed and modify the global storage, but it can also be traced instead to produce a change set that can be applied to the global stor- age. This provides a way to get a common format for the update of the global storage by both Move and Ethereum transactions. Another nice feature is that read/writes sets can also be extracted with Geth and can be used seamlessly in BlockSTM , the MoveVM's built-in parallel execution engine. The Move Executor re-uses existing EVM interpreters and integrates seamlessly with MoveVM to benefit from its parallel execution en- gine, thereby providing a parallel EVM. Moreover, using an existing EVM interpreter under the hood ensures that Move Rollup is EVM- equivalent and that executed EVM bytecode executed has the same behaviour as on L1.
3.3
Movement Stack
The Movement Stack provides support to create and deploy Move rollups. De- velopers are empowered to quickly spin up new Move Rollups in the network, 9 by selecting suitable components from the provided options in the Movement Stack, see Figure 4. The (configurable) components of the Movement Stack include: ● Sequencer: A rollup can opt-in for the default M1 , decentralized shared se- quencing service, but is provided with a default self-reliant sequencing mech- anism. ● Data Availability: We plan to support Ethereum EIP-4844 blobs, and major DA solutions (e.g., 0G, Avail, Celestia, EigenDA, Near). ● Settlement mechanisms: Optimistic (fraud proof), ZK (validity proof), Fast- finality (attestations).
Table 1. Example of Move Rollup configurations Table 1 illustrates a diverse range of Move Rollups within the Move Arena (Section 5), showcasing the extensive customization possibilities based on specific requirements. Moreover, using Movement Stack to deploy a Move Rollup pro- motes standardization across crucial infrastructure components, including wallet software, developer APIs, and block explorers. This standardization enhances interoperability and significantly improves the developer and user experience across the Move Arena ecosystem.
44
Fast-Finality Settlement
The modularity of the Move Rollup framework enables that the chain can be secured through a novel staking mechanism. This staking mechanism provides fast-finality 5 with high crypto-economic security. Since our Fast-Finality Settlement approach is s imilar to how Ethereum works in terms of security, we first recall some basic concepts. We then com- pare the level of security provided by Fast-Finality Settlement to optimistic and 10 validity rollups, see also Figure 5. Finally, we propose a combination of tra- ditional rollup settlements with the Fast-Finality Settlement, to provide both Ethereum security for settlement and fast finality.
4.1
Ethereum settlement and security
Ethereum's consensus is a proof of stake protocol, and validators have to stake some assets (32 ETH) to be incentivized to attest honestly about the status of a state transition. A validator that would be Byzantine (malicious) bears the risk 6 of being slashed of their stake. On Ethereum mainnet (L1), a state transition (creation of a new block) is final once it has received enough attestations from the validators. Enough stake is usually understood as 2/3 of the total stake – a super-majority – of all the validators. As a result, under the assumption that less than 1/3 of the validators are malicious, 7 if more than 2/3 of the validators have attested for a state transition, it must be correct as at least one the validators in this 2/3 is not Byzantine (it is honest). The security provided by the PoS mechanism is two-fold: ● liveness: in order to prevent a super-majority to attest a correct state tran- sition, an adversary would have to control more than 1/3 of validators. This is considered impossible when the total stake in the system is large (the probability that this happens is negligible.) ● safety : in order to force an incorrect state transition (e.g., double spending) an attacker would need to control 2/3 of the validators. Similarly to the Ethereum security: The level of security, i.e., the liveness of the Ethereum network and the safety (correctness of a state transition), increases with the total stake in the system. The higher the total skake, the more secure the network is. The level of security provided by the Ethereum network is commonly referred to as Ethereum security.
Security of validity and optimistic rollups
4.2
There are two main types of rollups, validity (ZK) rollups and optimistic rollups. Both settle on a Layer 1 (e.g., Ethereum mainnet) but use different settlement mechanisms. In a ZK-rollup, settlement happens when the ZK-proof of the state transition is accepted. This is done by submitting a verification transaction to the L1 verifier contract. Since the verifier is implemented as a contract on L1, the security level of the verification phase is Ethereum's security. Under the assumption that the ZK-proof system (proof generation and verifier contract) is correct, the ZK-proof is accepted if and only if the state transition is correct, hence ZK-rollup security : The level of security of a ZK-rollup is the same as Ethereum's security: a ZK-rollup inherits Ethereum's security. In an optimistic rollup, finality of transactions – after submitting the data and state commitments to Layer 1 – is achieved at the end of a time window, called the challenge period. It follows that security is conditional : the settlement happens if at the end of the challenge period (usually 7 days), no disputes have been successful. A dispute is a way of challenging a state transition. Validators can raise a dispute against a state transition if they think that it has been com- puted incorrectly. A trusted dispute resolution mechanism resolves the challenge: if the challenge is successful, the submitter of the incorrect state transition is slashed. Otherwise the challenging validator is slashed. Assuming at least one honest validator (e.g., watchtower ) re-executes each L2 state transition, it is impractical for the L2 to submit an incorrect new state. The level of security depends on where the dispute is settled. If it settles on Ethereum mainnet via a contract (e.g., as in [14]), and the contract that resolves the dispute is trusted (no bugs) then the security of the dispute resolution is Ethereum's security. Optimistic rollup security : The security of the dispute resolution mechanism of an optimistic rollup can inherit Ethereum's security. But if no validator checks a state transition before the end of the challenge period, then the level of security is zero. Finality of a state transition (i.e., finality of a transaction) on Ethereum mainnet is in the order of 12 minutes. On average the time to generate a ZK- proof is in the order of 10-15 minutes, and hence the finality of a transaction on a ZK-rollup is expected to be in the order of 20-25 minutes. For optimistic rollups, the standard challenging period is 7 days. In both cases, the time it takes to finalize a transaction can be prohibitively large for some, if not many applications. 4.3
Security of Fast-Finality Settlement
Fast-Finality Settlement provides security through a Proof of Stake (PoS) pro- tocol. In a PoS protocol, validators stake some assets (e.g., in native L2 tokens) to be incentivized to attest honestly about the status of an L2 state transition. If they are dishonest (they accept incorrect state transitions or reject correct state transitions) their stakes can be slashed. If they are honest validators, they are rewarded for their activity. The Fast-Finality Settlement uses a network of validators to provide fast and economically backed confirmation of correctly executed blocks. More precisely, the role of a validator is to confirm that the execution of a state transition is correct. 8 A state transition (that corresponds to the execution of a set of transactions) is final (irreversible) on a Move Rollup that utilizes only Fast- Finality Settlement when enough validators have confirmed the correctness of the state transition. For the sake of simplicity, we assume all the validators stake the same amount and enough means more than 2/3 of the validators. A simple mechanism for implementing Fast-Finality Settlement is: ● A set of validators stake some assets in a trusted L1 contract AttVerifK . ● For a given state transition of a Move Rollup, the validators broadcast their signed attestations (either approving or rejecting), and at the same time collect the signed attestations from others. ● When an validator has collected attestations representing more than 2/3 of the total stake, they submit them to contract AttVerifK. ● The contract AttVerifK verifies that the attestation signatures are valid, unique, and account for more than 2/3 of the stake. The state transition becomes final. Due to cryptographically protected signatures, a Byzantine validator cannot forge/tamper with the signed attestations. Assuming less than 1/3 of the valida- tors are Byzantine, and due to the 2/3 majority requirement, there cannot be a malicious actor who could submit enough attestations supporting an erroneous state transition. Moreover, during synchronous periods liveness is preserved, as 2/3 of stake are also sufficient to complete the attestation process. The verification that the threshold of 2/3 of the validators have confirmed a state transition is performed by contract AttVerifK. As a result the verification step inherits Ethereum security. The staking/slashing/rewarding functions are also executed on L1 with the same security level. Comparison with optimistic and ZK-rollups. The security of an optimistic rollup inherits Ethereum's security under the condition that an honest validator raises a dispute for each incorrect state transition. However, at present, opti- mistic rollups limit the list of challengers to reduce the risk of delay attacks in which an adversary could open as many disputes as they are willing to forfeit bonds for. 9 All of the above impose significant trust assumptions onto the user. Moreover, slashing penalties may not be economically large, compared to total stake protection as is the case in the validator network. In contrast to ZK-rollups, a Move Rollup that employs only Fast-Finality Settlement does not require expensive proof generation equipment. However, the most significant improvement delivered by Fast-Finality Settlement-based Move Rollups is the reduction in latency compared to both optimistic and ZK-rollups. Since attestations can be delivered in the order of seconds, we can provide fast- finality and substantially improves user experience. This compares to order of minutes in the ZK-rollup setting and days in the optimistic setting. The fast-finality mechanism is instrumental to interoperability and atomic cross-rollups transactions where a fast settlement time is required. Both opti- mistic and ZK-rollups lack in that respect. Hopefully, ZK-proof technology that permits real-time proving with specialised hardware, will be widely available in the near future, however, it is not clear at what point in time this is the case. Regarding optimistic rollups, they have an inherent requirement of extensive challenge periods (up to 7 days) to account for social engineering and attack vectors. In contrast, fast-finsality rollups can provide finality within seconds. A fast-finality Move Rollup rollup can be more secure than an op- timistic rollup and has faster finality than a ZK-rollup. If the total stake of the validator network is greater or equal to Ethereum valida- tors' total stake, then the fast-finality Move Rollup rollup even reaches Ethereum's economic security level. The overall security of the Fast- Finality Settlement approach depends on the total stake of validators. The staking, rewarding and verification steps inherit Ethereum secu- rity. We discuss a generalization of the staking mechanism, multi-asset staking, in Section 5.3.
Dual-layered finality
4.4
While Fast-Finality Settlement provides a rapid and economically robust form of transaction finality, it can be further strengthened by integrating it with the proven security guarantees of optimistic and ZK-rollups. By layering these approaches, we can offer a dual-layer security model that leverages the strengths of both systems. In this combined approach, Fast-Finality Settlement delivers a finality level that is backed by the economic security of staked validators, ensuring a rapid confirmation of transactions. The system can also invoke the traditional finality mechanisms of optimistic or ZK-rollups, which provide the additional security benefits derived from Ethereum's mainnet, albeit with the typical latency asso- ciated with these methods. This dual-layered finality model operates as follows: ● Fast-Finality Layer: Validators within the Fast-Finality Settlement frame- work rapidly confirm the correctness of state transitions, providing an initial layer of finality that is economically secure and swift, enhancing user expe- rience by reducing waiting times. ● Optimistic/ZK-Finality Layer: After the fast-finality is established, the transaction data is also processed through a secondary finality mechanism —either optimistic or ZK-rollup— on the Ethereum mainnet. This ensures that even if the fast-finality mechanism is compromised (e.g., due to a signifi- cant, albeit improbable, collusion of validators), the transaction still benefits from Ethereum's robust security guarantees. By combining these mechanisms, the system offers a highly secure and effi- cient transaction finality process: ● Improved User Experience: Users benefit from the fast and economically secure finality provided by the Fast-Finality Settlement, without sacrificing the long-term security provided by Ethereum's settlement layer. ● Flexibility and Resilience: This approach allows the system to adapt to various security needs, offering a balanced trade-off between speed and security based on the specific requirements of different applications. ● Enhanced Security: The integration of two independent finality mech- anisms significantly reduces the probability of a successful attack, as an adversary would need to compromise both the validator network and the secondary finality process. In conclusion, this dual-layered finality approach provides the best of both worlds: the swift and economically backed assurances of Fast-Finality Settle- ment, combined with the well-established security of optimistic or ZK-rollups. This hybrid model is particularly advantageous for applications requiring both immediate transaction confirmation and the highest possible security standards. 5
The Move Arena
The Move Arena is an advanced blockchain infrastructure designed to seamlessly integrate with our suite of in-house services and support a network of interoper- able rollups. This infrastructure facilitates the creation of a dynamic ecosystem where various rollups can operate efficiently and interact with one another. Its designed to meet the diverse needs of modern blockchain applications, offering enhanced interoperability, security, and resource efficiency. Move Arena is built upon several core components that enhance its function- ality and interoperability, see Figure 6. ● Movement: A framework for deploying and managing application-specific rollups. ● M1: A decentralized shared sequencer network that ensures seamless cross- rollup interoperability and enhances network security. ● Validator Network: A Proof-of-Stake based attestation system to ensure fast-finality and strong economic security for Fast-Finality Settlement, see Section 4. ● Multi-Asset Staking: Allows stakers to use multiple assets for staking, increasing flexibility and economic security. In the following sections we will explore the concepts of Movement, M1 and the Validator Network.
5.1
Movement: a network of application-specific chains
Application-specific chains are becoming the norm in the blockchain world. This is driven by the fact that applications like DeFi, gaming or supply chain ap- plications have different requirements for latency and throughput. Privacy or proprietary requirements may also need to isolate a chain and its dApps from 16 others. As a result, app-specific chains are proliferating across L1 networks like Avalanche, Cosmos, and Polkadot. We can take advantage of the modularity of our architecture (Section 3) to cater for specific needs, while at the same time providing cross-chain interop- erability and shared liquidity. This is achieved by creating a network of Move Rollups, called Movement, and integrating this network into our novel platform, the Move Arena (Figure 6). By sharing the same modular architecture, the chains in Movement are equipped with increased interoperability, can share the same bridge and Data Availability layer, and can profit from the fast settlement mechanism supplied in Move Arena. This design choice is consistent with the other L2 ecosystems, including Op- timism Superchain, Arbitrum Orbit, Polygon Supernets, zkSync Elastic Chain or Starknet appchains (layer 3). The Move Arena offers a cost-efficient and secure way of deploying new application-specific Move Rollups. Moreover, by being part of the Movement (rollup network) these chains are provisioned with cross- chain interoperability, as well as shared liquidity between them. In the sequel we outline the key features of our Move Arena. We discuss M1 (Section 5.2), our innovative shared sequencer solution and the concept of multi-staking (Section 5.3), which enhances the security and economic efficiency of our network.
5.2
M1: shared decentralized sequencer
M1 serves as a decentralized and shared sequencer for the Move Arena, diverging from the centralized sequencers commonly used in most rollups. This decentral- ized design enhances network robustness by eliminating single points of failure, promotes fairness and censorship resistance in transaction ordering, and allows permissionless participation [9]. To achieve consensus on transactions ordering, we employ a highly scalable, performant Byzantine Fault Tolerant (BFT) protocol. Centralized sequencers may offer faster preconfirmations than decentralized sequencers due to their centralized nature. However, being built with a highly scalable BFT consensus mechanisms and an efficient mempool mechanism, M1 can provide fast preconfirmations with only marginal increase in times, with the additional benefit of being economically backed, rather than based on trust. In regards to throughput a centralised sequencer could have less throughput limi- tations, however significant advances have been made on modern BFT protocols and which enable throughput levels that more than satisfy requirements. Finally, users may value interoperability features over latency questions. A distinguishing feature of M1 is its shared architecture across all Move Rollups. This shared sequencer approach is pivotal in enabling seamless interop- erability within the Move Arena ecosystem. By utilizing a common sequencing layer, M1 facilitates cross-chain atomic swaps and pooled liquidity across Move Rollups, significantly enhancing the network's overall security, functionality and efficiency. The sequencers are responsible for posting transaction data to the DA ser- vice chosen by each rollup. To mitigate data withholding attacks, we implement slashing mechanisms for non-compliant sequencers. While M1 manages trans- action ordering consensus, the Move Executor, powered by MoveVM, handles transaction execution. This separation of concerns optimizes network efficiency and security, laying the foundations for future innovations such as privacy en- hancements or opt-in censorship capabilities. Unlike other shared sequencer solutions, our stewardship of both the M1 and the Move Rollup framework allows for deeper integration and optimization. Our shared infrastructure approach not only reduces infrastructure burden for individual rollups but also creates a unified ecosystem where assets and liquidity can flow freely between Move Rollups, en- hancing overall user experience and network utility. The result is a highly interoperable and scalable L2 solution that combines the ben- efits of MoveVM.
Multi-asset staking
5.3
Our M1 shared decentralized sequencer uses a Proof of Stake (PoS) mecha- nism. The Fast-Finality Settlement also uses PoS to incentivize validators to be honest when attesting for new blocks. PoS, proven effective in ecosystems like Ethereum, requires candidates to stake native tokens, demonstrating com- mitment and adding capability to resist attacks. Single-asset staking requires
18
stakers to stake in a fixed crypto currency which means that they may have to swap assets before staking if they don't hold the token used in the staking protocol. This can be hurdle for stakers. This is why we will enable multi-asset staking, which is PoS that allows stakers to stake and get rewards in multiple assets (Figure 7, Image by myriammir on Freepik). This is why we will enable multi-asset staking, which is PoS that allows stakers to stake and get rewards in multiple assets. Multi-asset staking is convenient for stakers but comes with some challenges for the operator of the network: ● the staking pool is composed of several assets the prices of which may fluc- tuate, ● a PoS protocol usually relies on a super-majority of 2/3 of the total stake to finalize a decision (an ordering in the sequencer, a confirmation of a new block through the Fast-Finality Settlement). ● as a result of the previous two points, some stakers may obtain unreasonable power and a small fraction of them may control the 2/3 super-majority, which negatively impact crypto security. One solution to mitigate the problem is to use a (staking) pool token. Stakers stake arbitrary assets and are awarded pool tokens. When new stakers stake (resp. unstake) some assets, pool tokens can be minted (resp. burnt) and some re-balancing strategies [6] and liquidity curves choices have to be applied to manage the staking pool. The implementation of secure strategies that protect our stakers (e.g. from impermanent loss) is an active research topic. A critical feature in our multi-staking approach is the ability to stake without operating a node. This mechanism, called Delegation , maximises the amount of staked value and, therefore, boosts the economic security substantially.