Overview of Data Availability Solutions and Project Analysis

When discussing Layer 2(L2) scalability, the issue of data availability (DA) is a key consideration. The main challenge faced by L2 is to achieve a balance between security and cost. To this end, the industry has proposed two types of DA solutions: on-chain and off-chain.

On-chain Solution: Proto-Danksharding

On-chain solutions refer to Layer 2 continuing to use Ethereum as the data availability layer and relying on Ethereum to reduce data availability costs. Proto-Danksharding(EIP-4844) is an important proposal for reducing data availability costs on Ethereum. It introduces a new transaction format - Blob, allowing Layer 2 to temporarily store transaction data on the Ethereum consensus layer at a lower cost.

This means that Ethereum will become a real-time bulletin board in the future, where data will be deleted after being published for a period of time, and L2 will need to store all data backups by themselves. Proto-Danksharding is expected to go live in the Ethereum Cancun upgrade at the end of this year.

Off-chain Solutions

Off-chain solutions aim to find more economical alternatives for obtaining data availability, no longer using Ethereum as the DA layer. Depending on the degree of decentralization and security, off-chain solutions can be divided into four categories:

Validium

Validium is a highly centralized DA solution, where transaction data is managed by a single operator and published off-chain. Although this model can maximize privacy protection and reduce DA costs, it also carries a higher risk - if the operator encounters problems, user funds may not be recoverable.

Data Availability Committee ( DAC )

To reduce the risk of single points of failure, many Validium solutions are paired with DAC. DAC is similar to a consortium chain, composed of multiple trusted nodes, used to store copies of transaction data and disclose data when necessary. Although the operating costs are low, small DAC(8-10 people) still pose security risks.

Volition

Volition is a hybrid model that allows users to choose whether the data of a single transaction is published on-chain or off-chain. This flexibility enables it to inherit a certain degree of Ethereum's security.

Universal DA Solution

In addition to solutions targeting the Ethereum ecosystem, there is a category of general-purpose DA solutions that can serve more chains and projects. These solutions typically have their own validation nodes, block producers, and consensus mechanisms, but do not support smart contracts. Representative projects include EigenDA, Celestia, and Avail.

DA Layer Project Analysis

In a modular blockchain architecture, Ethereum almost monopolizes the consensus layer and the settlement layer, while the execution layer has also initially formed several major players. In contrast, the DA layer is still in its infancy. Here are a few popular DA layer projects:

StarkEx

StarkEx is a scaling framework developed by the StarkWare team, providing DA solutions for specific applications. It supports three DA modes: on-chain, Validium, and Volition. Currently, several well-known projects have adopted StarkEx to provide DA services.

zkPorter

zkPorter is an off-chain DA solution proposed by the zkSync team. It is an independent chain that ensures security through PoS consensus. Accounts on zkPorter can seamlessly interact with zkSync Era, but at a lower cost. However, there is currently no clear development progress for this solution.

EigenDA

EigenDA is a DA layer project developed based on EigenLayer. It is a middleware that does not have an independent consensus mechanism but obtains security through the ETH re-staking model of EigenLayer. Many L2 projects plan to integrate EigenDA to reduce costs and increase TPS.

Celestia

Celestia is a general-purpose DA public chain with independent validator nodes and a PoS consensus mechanism. Although the cost is higher than other off-chain solutions, the security is significantly enhanced. Celestium is a demonstrative L2 project that uses Celestia as the DA layer and Ethereum as the settlement and consensus layer.

Avail

Avail was originally a project of Polygon and is now operating independently. It is a DA public chain aimed at a multi-chain ecosystem, with relatively complex technology. Currently, Avail is in the testnet phase, offering various participation methods for developers.

Summary of Thoughts

The future roadmap of Ethereum shows that one of its key goals is to further reduce the cost of publishing data on L2 through EIP-4844. This means that Ethereum aims to continue maintaining the functionality of the DA layer rather than completely separating it.

For off-chain DA projects, after the relevant upgrades are completed on Ethereum, enhancing competitiveness will be a major challenge, in addition to focusing on lower costs. At the same time, whether the DA layer can give rise to large projects similar to Optimism and Arbitrum is also worth users' attention.