Founder Team Explains EigenDA Bringing Scalable Data Availability to Rollups

EigenDA brings scalable data availability to rollups.

Author: EigenLabs team, Translator: LianGuaixiaozou

You should already know what data availability is and why it is important for blockchain and rollup.

EigenDA is a secure, high-throughput, decentralized data availability (DA) service on Ethereum, using EigenLayer as the re-staking primitive. EigenDA, developed by EigenLabs, will be the first Active Verification Service (AVS) launched on EigenLayer. Once launched, restakers will be able to delegate staking to node operators who perform EigenDA verification tasks to earn service fees, and rollups will be able to publish data to EigenDA, obtaining lower transaction costs, higher transaction throughput, and the security, composability, and throughput of the entire EigenLayer ecosystem designed to scale with the number of stakers and service operators in the protocol.

We plan for EigenDA to contribute to the Ethereum ecosystem in the following ways:

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• An innovative DA solution for rollups dedicated to ultimate Ethereum scalability, with security provided by Ethereum stakers and validators, and value contributed by these stakers and validators. EigenDA is built on core ideas and the underlying Danksharding database, which is a significant upgrade to the Ethereum ecosystem and can be tested in practice with these technologies.

• A high-throughput and low-cost standard that supports the development of new on-chain use cases. EigenDA will support applications across multiplayer games, social networks, and video streaming, adopting flexible variable fee and fixed fee models.

• Preserving decentralization as a critical factor. In a shared security system like EigenLayer, if every node operator is required to download and store all chains used by the system, few node operators can achieve this, resulting in centralization risks. EigenDA is designed to prevent this centralization trend; it performs well in distributing work across multiple participating nodes, requiring each node operator to perform a small amount of work.

• Proof of programmable trust. EigenDA attempts to demonstrate that besides Ethereum consensus, Ethereum stakers and validators can also support critical Ethereum infrastructure. AVS (such as EigenDA) and AVS users (such as rollups using EigenDA) can achieve success in new business and token models based on modular components built on the Ethereum trust network.

We are pleased to see that several teams have expressed their intention to integrate EigenDA into their L2 infrastructure, including: Celo, transitioning from L1 to Ethereum L2; Mantle and its associated products outside the BitDAO ecosystem; Fluent, providing zkWASM execution layer; Offshore, providing Move execution layer; Layer N, providing zk-OP hybrid rollup designed for financial applications, and more.

We will continue to seek foundational layer partners to build EigenDA and invite various rollups to learn more about the protocol – especially those that are striving to achieve high throughput use cases (requiring 10 MBps or even higher throughput).

1. Technical Architecture

The diagram below shows the basic data flow of EigenDA.

• The sorter creates a transaction block and sends a request to disperse the data blob.

• The disperser erases and encodes the data blob into blocks, generates KZG commitments and KZG proofs, and sends these commitments, blocks, and proofs to the operating nodes of the EigenDA network.

• Rollups can use their own disperser or use a third-party dispersal service (such as EigenLabs) for convenience and shared signature verification costs. Rollups can optimistically use the dispersal service, so that in cases of unresponsive or audited service, the rollups can use their own disperser to obtain amortization advantages in optimistic mode without sacrificing anti-auditability.

• The EigenDA nodes verify the KZG commitments of the data blocks they receive, store the data, generate signatures, and return the signatures to the disperser for aggregation.

2. Technical Considerations

Now that we have a basic understanding of the architecture of EigenDA, let’s discuss the benefits and performance that this system aims to achieve. Here is a brief list of features that we believe are essential for a good and useful rollup data availability layer:

• Economics

• Throughput

• Security

• Customizability

We will look at each feature from the perspective of EigenDA.

(1) Economics

Today, many L2s use Ethereum as the data availability layer due to Ethereum’s cryptoeconomic security guarantees. This has led to extremely high and volatile costs as rollups compete with all other Ethereum users for limited block space based on congestion pricing. For example, both Arbitrum and Optimism have spent tens of millions of dollars on Ethereum’s calldata (data availability) costs this year alone, with monthly costs varying. One of the main value propositions of a data availability system is to significantly reduce these costs and provide rollups with a more predictable cost structure.

Cost Reduction

The costs associated with operating a DA system have three basic dimensions. Let’s analyze how EigenDA minimizes the underlying cost structure in each dimension:

• Capital Cost of Collateral: Collateral providers secure the security of the DA layer and may expect a certain proportion of returns to offset their opportunity costs. EigenDA reduces the capital cost of collateral by using EigenLayer, which adopts a shared security model that allows the same collateral to be used in various applications, creating economies of scale.

• Operating Costs: EigenDA does not require each node to download and store all the data. Instead, it uses erasure coding to divide the data into smaller data blocks, and only requires operators to download and store individual data blocks, which are a small part of the complete data blob. Compared to storing the entire blob, this reduces the cost for each node operator, making EigenDA “lightweight” and operable by many nodes. As more nodes join the EigenDA network, the resource costs for each node operator will decrease. This allows a large number of node operators to secure EigenDA at lower and marginally decreasing costs.

• Congestion Costs: Bandwidth utilization in all blockchains approaches system capacity, making data more expensive to combat congestion. EigenDA mitigates congestion in two ways: first, by having higher throughput, it attempts to make congestion a rare occurrence; second, by allowing bandwidth reservations, EigenDA can ensure the reserved throughput for rollups at discounted costs. To maintain flexibility, EigenDA also allows rollups to pay for throughput on-demand.

Rollup Economics

Rollup economics fundamentally differ from L1 economics because the cost of data availability (DA) is not only expensive but also unpredictable, as the cost is incurred by non-native tokens. This makes it difficult for rollups to make price commitments to users and subsidize initial adoption, as they have to bear the “exchange rate risk” between their own rollup tokens and the tokens used to pay for DA fees. In contrast, L1 pays fixed inflation and can provide a certain amount of transactions per second for free to attract users.

At EigenLayer, we are exploring a mechanism that allows rollups to pay participants in native rollup tokens at a predictable long-term booking rate, under conditions acceptable to EigenLayer restakers. This combines the inherent scaling advantage of a shared security system with the inherent advantage of stable native token payments to help bootstrap the use of rollups.

(2) Throughput

Throughput is another fundamental value proposition of DA systems. EigenDA aims to achieve horizontal scalability, so the more operators on the network, the greater the throughput supported by the network. In a private test of 100 nodes with standard performance characteristics, EigenDA has demonstrated throughput of up to 10 MBps and has a roadmap to scale to 1 GBps. This opens the door to bandwidth-intensive applications such as multiplayer games and video streaming on Ethereum.

EigenDA provides high throughput through its three design pillars:

• Decoupling DA and consensus. Existing DA systems couple the availability proof of data blobs with the ordering of data blobs in a “monolithic” architecture. Availability proofs are parallelizable, and nodes can independently prove the availability of different data blobs; however, ordering requires serialization of data blobs, resulting in noticeable consensus lag. While this coupling may be advantageous for the security of systems that serve as the ultimate source of ordering, it is neither necessary nor useful in DA systems designed to accompany the Ethereum blockchain, where DA systems have their own ordering systems that rollups rely on for settlement. By eliminating ordering and unnecessary complexity in designing a pure DA system, EigenDA significantly improves throughput and latency.

• Erasure coding. EigenDA allows rollups to acquire data they want to publish to EigenDA, break it down into smaller data blocks, and perform erasure coding on these data blocks before storing them as fragmented data. EigenDA uses KZG polynomial commitments (a core mathematical scheme for zero-knowledge proofs), requiring nodes to download only a small amount of data [O(1/n)] without the need to download the entire blob. Unlike systems that use fraud proofs to detect malicious data encoding, EigenDA adopts the form of KZG commitments as proof of validity, enabling nodes to verify the correct encoding of data.

• Direct unicast instead of P2P. Existing DA solutions use peer-to-peer (P2P) networks to transmit blobs, where operators receive blobs from their peers and then broadcast the same blobs to others. This greatly limits the achievable DA rate. In EigenDA, the Disperser sends blobs directly to EigenDA operators. By relying on unicast (direct communication) to distribute data, EigenDA can confirm DA within local network latency without the need for expensive gossip protocols. This eliminates the significant gossiping penalty brought by P2P and brings faster data delivery.

(3) Security

We use security as a general term, covering both security and liveliness, as well as decentralization and censorship resistance. The following features demonstrate the security of EigenDA:

• EigenLayer. By using re-staking, EigenDA borrows two different aspects of security from the EigenLayer system: economic security and decentralization. EigenDA is designed to leverage both EigenLayer and two different trust elements in the Ethereum ecosystem in a collaborative manner.

• Escrow Proof. In EigenDA, a key failure mode of node operators is that the actual storage time of data items does not meet the required time when signing the data items. To address this issue, EigenDA uses a mechanism called Escrow Proof, which was initially proposed by Justin Drake and Dankrad Feist of the Ethereum Foundation. With Escrow Proof, each node operator must regularly compute a function value, which can only be computed when they store the allocated blob block. If they verify the blobs without computing the function, the ETH held by the node can be seized by anyone with access to their data items.

• Dual Quorum. EigenDA also has a feature called Dual Quorum, which can require two independent quorums to prove the availability of data. For example, one quorum could be composed of ETH restakers (ETH quorum), and the second quorum could be achieved through a compromise of the rollup native quorum.

• Censorship Resistance. EigenDA provides higher instant censorship resistance than a coupled DA layer. This is because coupled DA architectures typically rely on a single leader or block proposer to linearly order data blobs, resulting in an instant censorship bottleneck. In contrast, in EigenDA, rollup nodes can directly scatter and receive signatures from the majority of EigenDA nodes, which improves censorship resistance against the majority of EigenDA nodes without being subject to a single leader.

(4) Security Analysis

As mentioned earlier, EigenDA is built on top of ETH staking through EigenLayer and uses erasure codes with configurable encoding ratios, which can be set by the rollup. There are three different perspectives to analyze the security of blockchain systems like EigenDA; let’s take a closer look at each perspective and how it applies to EigenDA as described above:

Byzantine Fault Tolerance (BFT): Assuming that some nodes are honest and fully comply with the protocol, while other nodes are malicious and can arbitrarily deviate from the protocol.

• DA is secure, meaning that as long as X% of the nodes are honest, data can be retrieved, where the range of X can be from 10% to 50%, depending on the encoding ratio.

• Nash Equilibrium Model: Assuming independent actions of nodes with different collusions, analyzing the economic incentive mechanisms that each node or small-scale collusion nodes follow to comply with the protocol.

• As long as the collusion is less than (1-X), storing data and providing data to users is Nash Equilibrium: storing data is ensured as an equilibrium through Escrow Proof, which penalizes nodes that do not store data by seizing their ETH; providing data is ensured as an equilibrium because data is scattered across many nodes, forming a competitive market for data provision.

Pure Encrypted Economy Model: Assuming that all staking is held by the same node and modeling the cost of economic corruption.

• As long as the data is available, or equivalent to being available, as long as X% of the nodes are honest, any ETH staked by a node that does not host data will be confiscated. However, EigenDA does not have unconditional cryptographic economic security; if all nodes collude and conceal data, they may not be able to confiscate them. In the Dual Quorum model described earlier, staked tokens are ETH and rollup native tokens, and even if it is impossible to confiscate ETH, rollup can confiscate native tokens.

As we can see, EigenDA is built on a trust model, which requires not only economic trust from ETH staking but also decentralization and independence of node operators for secure operation. Fortunately, EigenLayer allows EigenDA to borrow these two trust mechanisms from Ethereum.

(5) Customizability

Rollup developers can flexibly adjust parameters to implement EigenDA according to their needs. The modular nature of EigenDA allows rollup to customize security/liquidity trade-offs, staked token models, erasure coding, available payment tokens, and so on.

As discussed earlier in this document, some of the most important flexible decisions in EigenDA are economic decisions. For example, rollup can choose to use dual quorum staking, where they stake their own tokens to ensure data availability; or rollup can choose an on-demand or pre-scheduled cost structure.

3. Strategic Considerations

Finally, we believe that in addition to the technical features mentioned above, EigenDA also provides strategic value to rollup.

• Ethereum stakers and validators are the beating heart that powers EigenLayer and, accordingly, also power EigenDA. By adopting EigenDA, rollup may align with these Ethereum stakeholders who explicitly value decentralization, censorship resistance, open-source software, and composable, permissionless innovation.

• EigenDA is planned to be the first of many AVSs launched in the EigenLayer ecosystem. We anticipate that as the number of AVSs grows, they will have composability advantages among them, which will benefit the end users of these AVSs, and we hope to include a variety of rollups. For example, after EigenDA, we expect to see use cases for launched AVSs including sorting, fast confirmation, watcher networks, bridging, fair ordering, and even artificial intelligence.

• EigenDA is in the early stages of a long journey to realize its grand vision. The EigenLabs team is looking for base layer partners who are willing to work closely with us on EigenDA and also hope to collaborate on multiple projects in the long term to eventually become long-term partners. We hope this is an opportunity to jointly drive the Ethereum ecosystem towards more open innovation, and we look forward to supporting your project as much as possible.

4. Path Forward

In line with our design philosophy, we have a phased EigenDA roadmap, where various features of EigenDA will be built and released step by step. The first version of EigenDA will be launched on the testnet later this year.

We will continue to update Blocking; if you have any questions or suggestions, please contact us!