TLDR

• Cross-chain asset transfers are complex and expensive due to the lack of unified standards and varying architectures and consensus mechanisms of different blockchains. Existing third-party bridges face trust and security challenges, and centralized bridges need to maintain liquidity, passing costs onto users. One-click chain deployment, akin to solving the trilemma, is a compromise for asset bridging.
• Market maturity is led by OP Stack and Superchain, with Base being a successful example. AggLayer’s native compatibility with Ethereum makes it more easily accepted, but it needs to ensure the security and reliability of the aggregation process. Elastic Chain’s success depends on the development of ZKsSync; in the short term, the market favors OP, while in the long term, it leans towards ZK.
• In the context of insufficient industry innovation, DeFi remains the main application for Rollups. Currently, DePIN, RWA, and large GameFi projects are less likely to appear on Rollups, while SocialFi and NFT markets may emerge, but their market popularity is uncertain. The overall Matthew effect suits blockchain, and the trend of infinitely issuing Rollups warrants long-term attention to the leaders and short-term focus on the mid-to-lower tiers.

1. Connecting the Islands of Chains: The Problem with Bridges

When transferring assets across chains, each blockchain has unique architectures, consensus mechanisms, state proofs, and state transitions, lacking a unified standard and interoperability, making cross-chain communication and data exchange complex. These verification processes are often too expensive to execute on-chain. This limitation has led to the proliferation of multi-signature committees to verify the state of other chains. Therefore, there is no universal decentralized standard or protocol that can achieve interoperability among all blockchains, restricting the free flow of assets across different blockchains.

To facilitate cross-chain asset transfers, numerous third-party bridges have emerged, but these bridges face significant network security challenges related to trust issues. Even if centralized bridges can ensure complete security, they still need to maintain sufficient liquidity on each integrated chain, passing these operational costs onto users. Currently, the inability to meet native decentralized asset bridging and the difficulty of trusting third-party bridges have led ZKsync, Polygon, and Optimism to introduce their more native solutions with Elastic Chain, AggLayer, and Superchain Explainer for localized multi-chain expansion.

2. ZKsync3.0: Elastic Chain

Image source: zksync.mirror

In 2023, Matter Labs, the main development company behind ZKsync, released the ZK Stack, a toolkit allowing developers to build their own blockchains based on ZKsync technology. Essentially, these custom chains will be interconnected through Elastic Chain, transforming ZKsync 3.0 from a single Ethereum L2 to The Elastic Chain.

The core upgrade of the ZKsync 3.0 protocol was released on June 7, 2024, making it the most complex upgrade of ZKsync to date. It reconfigures the ZKsync L1 bridge into a shared router contract to support an expanding network of interoperable ZK chains. The ZK Stack framework enables native, trustless, and low-cost interoperability between chains.

According to Matter Labs, “Elastic Chain is an infinitely scalable network composed of ZK Chains (rollups, validiums, and volitions) that ensures their security through mathematical verification methods and achieves seamless interoperability under a unified and intuitive user experience. It aims to make interoperability within the ZKsync ecosystem smoother and more efficient.”

2.1 Elastic Chain Architecture

Elastic Chain doesn’t rely solely on ZK technology and cannot simply add ZK proof “patches” to other non-ZK multi-chain systems. At a high level, its network is realized through three components: ZK Router, ZK Gateway, and ZK Chains.

1.ZK Router:

• Core Routing Mechanism: ZK Router is the main routing component of the ZKSync 3.0 architecture, responsible for managing and coordinating communication and data transmission between different chains and nodes in the network.
• Cross-chain Communication: Using efficient cross-chain communication protocols, ZK Router ensures fast and secure data transfer between different chains, enhancing overall network interoperability and performance.

1. ZK Gateway:

• Entry and Exit Nodes: ZK Gateway acts as the entry and exit nodes for the ZKSync 3.0 network, handling interactions between external blockchains (e.g., Ethereum mainnet) and the ZKSync network.
• Asset Bridging: Responsible for bridging and transferring assets between external blockchains and the ZKSync network, ensuring secure and efficient asset flow between different chains.
• Transaction Aggregation: Aggregates user transactions into batches, then generates zero-knowledge proofs, submitting them to external blockchains for verification, reducing on-chain data load and transaction fees.
• Middleware: It can be understood as middleware deployed between Ethereum and ZK Chains to facilitate comprehensive interoperability among ZK Chains.

1. ZK Chains: They ensure transaction validity and security through the generation and verification of zero-knowledge proofs, submitting the results to the ZK Router for aggregation and coordination. They are interconnected with the L1 smart contracts via the ZK Gateway, fully independent, customizable, and built using the ZK Stack.

According to ZKsync, the Gateway is a key component of the Elastic Chain, enabling seamless ZK Chains settlement to Ethereum. By submitting proofs and data to Ethereum via the Gateway, the following advantages are realized:

• Cross-batch and Cross-chain Proof Synthesis: Reducing L1 verification costs.
• State Delta Compression: Compressing small batch data sent to the Gateway and efficiently forwarding it in large batches to L1.
• Faster Finality: Verifying chain proofs and preventing conflicts for low-latency cross-chain bridging, reinforced by the staking of a large number of validators. ZK Chains do not need to trust other chains.
• Liveness: Each ZK Chain’s liveness is independently managed by its validators; the Gateway does not affect its liveness. Chains can freely leave the Gateway.
• Censorship Resistance: Cross-chain forced transactions will be cheaper than regular L1 censorship-resistant transactions, making it more accessible to all users.

ZK Chains do not need to use the ZK Gateway and can settle directly to Ethereum, freely choosing to leave the ZK Gateway network without affecting their chain’s security. They can switch between using the ZK Gateway and settling directly to Ethereum. The ZK Gateway will be operated by a decentralized, trustless validator cluster to ensure network resilience and reliability. Participating in this decentralized validation process requires an ERC20 token. ZKSync network governance will designate a token for this purpose (possibly the ZK token).

Validators will collect bridging fees and fees per byte of state delta data published to the ZK Gateway. This incentivizes validators to join the ZK Gateway, as their revenue can multiply with more value transacted on-chain. Additionally, due to the re-compression service provided by validators, settling data through the ZK Gateway will be cheaper than settling directly on the Ethereum network, which may be why most ZK Chains will likely choose to join.

3. Polygon 2.0: Agglayer

Image source: Polygon Agglayer

3.1 Origins of Agglayer Design

Similar to OP Stack and ZK Stack, blockchains created using Polygon CDK can directly integrate into Agglayer, leveraging its unified bridging and security services to achieve interoperability with other blockchains. This forms the core architecture of Polygon 2.0.

The core idea of Agglayer originates from the Shared Validity Sequencing design proposed by Umbra Research. This design aims to achieve atomic cross-chain interoperability between multiple Optimistic Rollups. By using a shared sequencer, the system can uniformly handle the transaction ordering and state root publishing for multiple Rollups, ensuring atomicity and conditional execution.

To implement this, the following three components are needed:

• Shared Sequencer: Receives and processes cross-chain transaction requests.
• Block Construction Algorithm: The shared sequencer is responsible for constructing blocks that include cross-chain operations, ensuring their atomicity.
• Shared Fraud Proofs: Implements a shared fraud proof mechanism among relevant Rollups to enforce cross-chain operations.

Since existing Rollups already have the capability of bidirectional message passing between Layer 1 and Layer 2, Umbra has only added a MintBurnSystemContract (Burn and Mint) to complement the three components.

Workflow:

• Burn Operation on Chain A: Can be called by any contract or external account and, upon success, is recorded in the burnTree.
• Mint Operation on Chain B: Upon successful execution by the sequencer, it is recorded in the mintTree.

Invariants and Consistency:

• Consistency of Merkle Roots: The Merkle roots of burnTree on Chain A and mintTree on Chain B must be identical to ensure the consistency and atomicity of cross-chain operations.

System Operation:

• The shared sequencer is responsible for publishing the transaction batches and declared state roots of both Rollups to Ethereum. It can be centralized or decentralized (like Metis). The sequencer receives transactions and constructs blocks for Rollup A and B. If a transaction on A interacts successfully with MintBurnSystemContract, it attempts to execute the corresponding Mint transaction on B. If the Mint transaction is successful, it includes both the Burn transaction on A and the Mint transaction on B; if it fails, it excludes both transactions.

3.2 Core Components of Agglayer:

In Polygon 2.0’s Agglayer, Unified Bridge and Pessimistic Proofs are its core components.

1. Unified Bridge

Technical Framework:

• Cross-chain Communication: The core of the Unified Bridge is to achieve seamless communication between different chains. It enables data and asset transfer between different Layer2 solutions and the Ethereum mainnet through cross-chain communication protocols.
• Liquidity Aggregation: This bridge aggregates liquidity from different Layer2 solutions, allowing users to freely move assets between chains without concerns about liquidity fragmentation.

Implementation Logic:

• Message Passing: The Unified Bridge achieves cross-chain communication through a message passing mechanism. Messages contain relevant transaction information and are transmitted between chains via the bridge protocol.
• Asset Locking and Releasing: When users lock assets on one chain, the Unified Bridge releases equivalent assets on the target chain. This process uses smart contracts to ensure security and transparency.
• Interoperability Protocols: To ensure interoperability between different chains, the Unified Bridge uses standardized interoperability protocols. These protocols define how to handle cross-chain transactions, verify transaction validity, and resolve potential conflicts.

Source: Aggregated Blockchains: A New Thesis

1. Pessimistic Proofs

Technical Framework:

• Security: Pessimistic Proofs are a security measure designed to prevent fraudulent transactions. It introduces additional verification steps during transaction validation to ensure all transactions are valid.
• Delayed Verification: Unlike Optimistic Proofs, Pessimistic Proofs assume transactions may be malicious and perform comprehensive verification before confirmation.

Implementation Logic:

• Initial Verification: After a transaction is submitted, the system immediately performs preliminary verification, including checking the basic transaction information and signature validity.
• Deep Verification: Upon passing initial verification, the transaction enters the deep verification stage. The system calls a series of smart contracts to check the transaction’s complexity and potential risks.
• Dispute Resolution: If any issues are found during verification, the system triggers a dispute resolution mechanism. This allows users and validators to submit additional proofs to resolve disputes and ensure the final validity of the transaction.

By integrating Unified Bridge and Pessimistic Proofs, Agglayer provides a highly secure, scalable, and interoperable blockchain environment. These components not only enhance the system’s security but also simplify cross-chain transactions, allowing users to interact across different chains more easily. For more details, refer to YBB Capital’s previous article “From Modular to Aggregate: Exploring the Core of Polygon 2.0’s Agglayer” .[1]

4. Optimism: Superchain Explainer

In 2023, Optimism pioneered the path for one-click chain deployment, with its initial project being the OP Stack, establishing a standard for a unified network. The OP Stack serves as the launch platform for the Ethereum scaling solution, The Optimism Superchain, and acts as the hub for interaction and transactions among all L2s built using the OP Stack.

The Optimism Superchain shares a common OP Stack development stack, bridging, communication layer, and security, ensuring that various chains can coordinate and function as a single unit. This structure can be broken down into five distinct layers, each with its specific purpose and function:

1. Data Availability Layer: Determines the primary source of raw input for chains based on the OP Stack, primarily through Ethereum DA.
2. Sequencing Layer: Controls how user transactions are collected and forwarded, usually managed by a single sequencer.
3. Derivation Layer: Processes raw data into input for the execution layer, primarily using Rollup technology.
4. Execution Layer: Defines the system state structure and transformation functions, with the Ethereum Virtual Machine (EVM) as the central module.
5. Settlement Layer: Allows external blockchains to view the valid state of OP Stack chains through proof-based fault verification.

Compared to Elastic Chain and Agglayer, Optimism Superchain was the earliest to enter the market, securing a significant presence. It has notably launched Base, which has accounted for a substantial portion of daily gas expenditures, reflecting its high on-chain activity.

Source: Dune Optimism — Superchain Onchain Data

5. Subjective Thoughts on One-Click Chain Deployment

5.1 Competitive Analysis of AggLayer, Superchain, and Elastic Chain

(This section represents the author’s personal views.)

The above three scaling solutions extend the narrative of their respective Rollup expansions. From the perspective of market maturity, OP Stack and Superchain were the first to capture the market, with Base being the most successful representative.

AggLayer has an advantage in terms of native compatibility, as it can operate directly on the existing Ethereum network without requiring significant modifications to the underlying protocol. This makes it more easily accepted by existing Ethereum users and developers. The challenge lies in ensuring the security and reliability of the aggregation process.

The preliminary judgment for Elastic Chain is to assess the development and community building of the ZKsync ecosystem. If ZKsync itself does not thrive, Elastic Chain may face challenges in attracting developers and maintaining community enthusiasm. From both market and technical perspectives, the short-term outlook favors OP, while the long-term potential lies with ZK.

However, the inherent issue with all three solutions is the relatively centralized nature of Rollup. Recently, the Based Rollup scaling solution has emerged as a potential competitor. It transfers the sequencer directly to L1, i.e., Ethereum itself, eliminating the need for additional sequencers or complex validation steps for L2. This more native scaling approach, despite some potential MEV issues, is worth monitoring for future developments.

Source: ZKsync — Introducing the Elastic Chain

5.2 Future Trends and Application Innovations for Rollup

Overall, with the promotion of “one-click chain deployment,” the number of Rollups as the main scaling solution for Ethereum will continue to increase. Even with the 2023 boom in the Bitcoin ecosystem, its non-native expansion borrowed many Ethereum scaling concepts. Amidst limited market innovation, Rollup application innovation and impact may be constrained.

For each VM chain, regardless of market changes, TVL remains a key indicator, so the earliest applications are likely to be various DeFi protocols. Additionally, SocialFi protocols and NFT trading markets may emerge.

In other sectors, DePIN may struggle to develop on Rollup and L1, with leaders possibly appearing on Solana. The RWA concept is more likely to develop on L1 but lacks confidence on Rollup. GameFi will also emerge, but large-scale games will only have opportunities on Rollups focused on GameFi. Therefore, the most certain applications at present are still DeFi-related.

However, the Matthew effect is pronounced in the blockchain space. With the advent of the multi-chain era, resources will concentrate on leading projects, where the strong get stronger, and the weak are eliminated.

About YBB

YBB is a web3 fund dedicating itself to identify Web3-defining projects with a vision to create a better online habitat for all internet residents. Founded by a group of blockchain believers who have been actively participated in this industry since 2013, YBB is always willing to help early-stage projects to evolve from 0 to 1.We value innovation, self-driven passion, and user-oriented products while recognizing the potential of cryptos and blockchain applications.

Website | Twi: @YBBCapital

Extended Link:

1. From Modular to Aggregate: Exploring the Core of Polygon 2.0’s Agglayer

https://medium.com/ybbcapital/from-modularity-to-aggregation-exploring-the-core-of-polygon-2-0s-agglayer-e492dd05ceb9

Reference Articles:

1. Introducing the Elastic Chain

https://zksync.mirror.xyz/BqdsMuLluf6AlWBgWOKoa587eQcFZq20zTf7dYblxsU

1. zkSync Protocol Upgrade v24: New precompiles, more blobs, Validiums, and more. #519

https://github.com/zkSync-Community-Hub/zksync-developers/discussions/519

Disclaimer：

1. This article is reprinted from [medium], Forward the Original Title‘Ethereum’s Evolution: The Infinite Potential of Layer 2 Expansion and One-Click Multichain’, All copyrights belong to the original author [YBB]. If there are objections to this reprint, please contact the Gate Learn team, and they will handle it promptly.

2. Liability Disclaimer: The views and opinions expressed in this article are solely those of the author and do not constitute any investment advice.

3. Translations of the article into other languages are done by the Gate Learn team. Unless mentioned, copying, distributing, or plagiarizing the translated articles is prohibited.