Overview of Data Availability Solutions

In the field of blockchain scalability, one of the main challenges faced by Layer2(L2) is the issue of data availability (DA), which requires a balance between security and cost. Currently, two types of DA solutions have emerged, on-chain and off-chain, to address this challenge.

On-Chain Solutions: Proto-Danksharding

On-chain solutions refer to Layer 2 continuing to use Ethereum as the Data Availability layer, and reducing data availability costs through Ethereum itself. Proto-Danksharding(EIP-4844) is a proposal made by Ethereum to reduce DA costs. It introduces a new transaction format - Blob, which allows Layer 2 to perform non-permanent storage in Blob format on the Ethereum consensus layer, thereby providing a more economical data availability option for Layer 2.

This means that Ethereum will serve as a real-time bulletin board in the future, where the data on the bulletin board will be deleted after a certain period, and L2 needs to store all the data backups by itself. Proto-Danksharding is expected to be implemented in the Ethereum Cancun upgrade at the end of this year.

Off-chain Solutions

Off-chain solutions no longer use Ethereum as the DA layer, but seek more economical data availability methods. Based on differences in decentralization and security, off-chain solutions can be divided into four categories:

Validium

Validium is a highly centralized DA solution. In this model, transaction data is managed by a centralized operator and published off-chain. Although this approach maximizes the protection of the privacy of the parties involved and minimizes DA costs, it also carries high risks. If the off-chain operator fails or engages in malicious behavior, user funds may become unrecoverable.

Data Availability Committee ( DAC )

To reduce the single point of failure risk brought by a single operator, most Validium solutions currently use DAC. DAC is similar to a consortium chain, consisting of multiple trusted nodes. These nodes will keep copies of transaction data and make the data public when the operator encounters issues, facilitating users in withdrawing funds.

The operational cost of DAC is relatively low, but from a security perspective, small-scale DACs with 1-10 people are still vulnerable to private key theft or collective malicious behavior, which may result in on-chain funds being frozen or stolen.

( Volition

Volition is a hybrid model that allows users to choose whether the data of individual transactions is published on-chain or off-chain. For example, in a DEX that adopts this model, users can control multiple accounts and, when a transaction is needed, transfer assets to an off-chain data account for frequent and low-cost trading, and then return the assets to the on-chain data account after the trading is completed.

Compared to pure Validium, Volition can partially inherit the security of Ethereum.

) Universal DA Solution

In addition to solutions under the Ethereum ecosystem, there is also a type of general-purpose DA solution that can not only provide data availability for Ethereum's L2 but also serve more blockchains and projects. The overall idea of this type of solution is to enhance the security of data availability to achieve a public chain-level security standard. They typically have independent verification nodes, block producers, and consensus mechanisms, but lack smart contract functionality.

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Overview of DA Layer Projects

Under the trend of modular blockchain development, Ethereum has almost monopolized the consensus layer and settlement layer, while the execution layer has formed several major players after fierce competition. The DA layer is still in its infancy, and here are several popular DA layer projects:

( StarkEx

StarkEx is a framework developed by the StarkWare team that provides scalability solutions for specific applications, including data availability solutions. It offers three modes of DA: on-chain, Validium, and Volition, with the Validium solution integrating DAC to enhance security. Projects currently using StarkEx for DA include dYdX v3, Immutable, Sorare, and DeversiFi.

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( zkPorter

zkPorter is an off-chain DA solution proposed by Matter Labs in April 2021. It is an independent chain specifically designed for L2 to publish transaction data, maintained securely through a PoS consensus mechanism. zkSync token holders can stake their tokens to become guardians of zkPorter, validating and signing blocks.

According to Matter Labs' vision, accounts on zkPorter can seamlessly interact with accounts or contracts on ZK Rollup)zkSync Era###. From a user perspective, the main difference is that the fees for zkPorter accounts will be significantly lower.

However, despite the zkPorter concept being proposed for several years, there has been no concrete progress, and Matter Labs has not disclosed any information regarding the zkPorter testnet and development progress.

( EigenDA

EigenDA is a DA layer project developed based on EigenLayer. Unlike general DA projects, EigenDA is a middleware that does not have its own consensus mechanism; its security is obtained through the re-staking model of Ethereum validators in EigenLayer.

EigenDA is the first active validation service on EigenLayer ) AVS ###. Re-stakers will re-stake ETH to EigenDA to perform data validation services for rewards, while buyers ( L2) will publish data to EigenDA for lower transaction costs and higher TPS.

Although EigenDA has not yet launched on the testnet, several teams plan to integrate it into L2, such as Mantle, Layer N, and Offshore.

( Celestia

Celestia is a general-purpose DA public chain with independent validation nodes and a PoS consensus mechanism. Although the cost is relatively higher compared to other off-chain DA solutions, the security is significantly enhanced.

Celestium is a Layer 2 chain that uses Celestia as the DA layer and Ethereum as the settlement and consensus layer. The DA implementation method of Celestium is as follows:

1. Celestium will continue to upload proof data to Ethereum, but will publish transaction data to Celestia;
2. The validator nodes of Celestia send the data availability proof signatures to the DA Bridge Contract deployed on Ethereum for verification and storage;
3. L2 contracts on Ethereum can access this data at any time.

Celestia has completed two rounds of financing, including a $1.5 million seed round in March 2021 and a $55 million financing in October 2022, attracting participation from several well-known VCs.

In September this year, Celestia announced an airdrop plan, which will airdrop TIA), Celestia's native asset ###, to 7,579 developers and 576,653 on-chain addresses. This initiative has further sparked interest in the modular blockchain and DA layer track.

( Avail

Avail was initially a project established by Polygon Labs in 2020, aimed at solving data availability issues. In March of this year, Avail became independent from Polygon and operates as a standalone DA public chain, no longer limited to the Polygon or Ethereum ecosystems.

On a technical level, Avail is more complex than Celestia. Its mainnet is expected to launch in the first quarter of 2024 and is currently in the testnet phase. The Avail testnet has advanced to the second stage, and users can participate in various ways:

• Get testnet token AVL, explore staking and nomination features
• Develop modular blockchain applications or chains integrated with Avail
• Join the testnet as a validator or light client to participate in the data verification process.

Avail is currently conducting a testnet incentive program called "Clash of Nodes Challenges", but simply running a node will not earn points; users need to apply to become a Validator to earn points, and the application process is quite complex. Regular users can continue to follow the release of new tasks.

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Conclusion

The future roadmap of Ethereum shows that after The Merge, the next phase, The Surge, focuses on further reducing data publication costs for L2 through EIP-4844. This indicates that Ethereum aims to retain the functionalities of the DA layer, settlement layer, and consensus layer, while only separating the execution layer.

After the Cancun upgrade is completed, the off-chain DA layer project (, especially the DA public chain ), may directly face business competition with Ethereum. In addition to focusing on lower costs, they also need to consider how to enhance their competitiveness.

Celestia has chosen to issue tokens at this time to incentivize developers and active users, which may also have strategic considerations for seizing opportunities and winning people's hearts. For users, it is worth paying attention to whether important projects similar to Optimism and Arbitrum will emerge in the competition at the DA layer.