Introduction

With the development of blockchain technology, decentralized data availability has emerged as one of the important directions to address one of the three significant challenges of blockchain. Against this backdrop, projects such as Celestia, EigenLayer, Avail DA, and NEAR DA have emerged. They aim to address blockchain scalability and performance issues through innovative technologies and designs, thereby promoting the development of the blockchain ecosystem.

Data Availability Issue

Introduction to Data Availability

In today’s blockchain architecture, Data Availability (DA) is a crucial component. Unlike traditional single-blockchain setups, modular blockchains decompose the network into various functional layers, including execution, Data Availability (DA), consensus, and settlement layers. Among these layers, the Data Availability (DA) layer is responsible for storing the data necessary to verify the validity of transactions.

Source: docs celestia

Data Availability Issue

In blockchain and distributed ledger technology, the issue of data availability is a critically important challenge. At its core, it involves ensuring that all transaction data can be openly accessed and verified on the network, which is crucial for maintaining the integrity and security of blockchain systems.

In blockchain systems, the transaction data of each block needs to be verified by network nodes. However, ensuring that this data is reliably distributed throughout the entire network and ensuring that all participants have equal access to it is a crucial issue.

Why is Data Availability Important?

• Off-chain transactions: L2 solutions aim to handle transactions outside the main chain to improve the scalability of the entire system. However, this approach may bring some challenges because L2 does not immediately record all transaction data on the L1 blockchain, which may lead to difficulties in verifying the integrity and accuracy of all transaction data.
• Dependency on the security of Layer 1: Despite the ability of L2 networks to operate independently and process transactions, they still rely on the L1 network to ensure overall security. Ensuring the integrity and accuracy of data transmission from L2 to L1 is crucial for maintaining the integrity of the entire network.
• Dependency of solution mechanisms on data: L2 networks can apply mechanisms such as fraud proofs to address potential disputes. The effectiveness of these mechanisms depends on the availability and accessibility of transaction data.
• Transparency and trust issues: Transparency is a crucial principle in blockchain technology. In L2 networks, any problems regarding data availability may lead to a trust crisis because users may not be able to verify the authenticity of transactions independently.
• Increased complexity of verification: The introduction of L2 increases the complexity of ensuring the accuracy of data returned to the main chain, which also brings risks of data availability issues, thereby affecting the network’s reliability.

DA Solutions

There are various solutions for the DA layer, broadly categorized into on-chain and off-chain types.

In L2 solutions, data availability typically employs two different approaches:

• On-chain data availability: All transaction data is stored on the L1 chain, providing higher security but at a higher cost. This means L2 still utilizes Ethereum as the DA layer and relies on Ethereum to reduce the cost of data availability.
• Off-chain data availability: Data is stored off-chain, with only encrypted information digests (hash values) stored on-chain. This approach is more cost-effective but requires external entities to retrieve data. In other words, Ethereum is no longer used as the DA layer, and instead, more economical methods are sought for data availability. Depending on the degree of decentralization and security, off-chain solutions can be divided into four types: Validium, Data Availability Committees (DAC), Volition, and general-purpose DA solutions.

Overview of DA Track Projects

There are relatively few participants in the Data Availability (DA) domain. Besides Ethereum, there are some key projects such as Celestia, EigenLayer, Avail, and NEAR DA, each with its characteristics regarding project progress. In DA projects, factors such as security, customizability, interoperability, and cost are crucial.

Celestia

Celestia is the first project to adopt a modular Data Availability (DA) network, aiming to scale the growth of user numbers securely. Its modular design allows anyone to launch an independent blockchain.

As a leader in modular public chains, Celestia is developed based on the Cosmos SDK and is committed to enhancing data availability. On the mainnet, Celestia has achieved significant competitive advantages.

Technical Features

Celestia’s design separates execution, consensus, settlement, and data availability. This modular structure allows for specialization and optimization at each level, enhancing the overall efficiency and scalability of the network.

Source: docs celestia

1. Data Availability Sampling (DAS)

Data Availability Sampling (DAS) is a method that allows light nodes to verify data availability without downloading the entire block. By randomly sampling data blocks, light nodes can ascertain whether this data can be successfully retrieved and validated, thus inferring data availability for the whole block.

Source: docs celestia

1. Namespaced Merkle Tree (NMTs)

NMTs enable block data to be divided into separate namespaces for different applications. This means that each application only needs to download and process data related to it, significantly reducing data processing requirements.

Source: docs celestia

Feature Analysis

• The Rollups in Celestia differ from Ethereum Rollups in that their operation on Celestia independently determines the specification state, increasing node autonomy. Nodes can choose their operating mode freely through soft and hard forks, reducing reliance on centralized governance and promoting more experimentation and innovation.
• Celestia’s Rollups feature characteristics unrelated to execution, meaning they are not limited to EVM-compatible designs. This openness provides a broader space for virtual machine innovation, contributing to technological advancement.
• Celestia simplifies the deployment process of blockchains. Utilizing tools like Optimint, developers can quickly deploy new chains without worrying about the complexity and high cost of consensus mechanisms.
• Celestia separates active state growth from historical data storage, providing a more efficient resource pricing mechanism. This approach reduces mutual interference between execution environments, improving user experience.
• Celestia’s architecture supports the creation of trust-minimized bridges, allowing different chains to securely interoperate, thereby enhancing the security and interoperability of blockchain clusters.

Celestia is the first modularly designed DA network whose primary goal is to scale amidst user growth securely. Its modular structure simplifies the launch of independent blockchains. With its unique approach and technological innovations, Celestia is poised to play a significant role in the blockchain industry. It focuses on addressing challenges faced by blockchain, particularly scalability issues, while maintaining security and decentralization, making it a vital participant in the evolving blockchain ecosystem.

Eigen DA

EigenLayer is a re-staking protocol that allows users to re-stake ETH, lsdETH, and LP Tokens on other platforms, such as sidechains and oracles, and receive validation rewards as nodes. On the other hand, Eigen DA is a decentralized data availability (DA) service built on Ethereum using EigenLayer Restaking and will become the first Active Validation Service (AVS) on EigenLayer.

Technical Features

• Enhancing Ethereum’s Data Availability Capability: Eigen DA leverages Blob block data and KZG commitments, enhancing Ethereum’s data availability capability with upgraded Blob block data and KZG commitments after the Canquan upgrade. Validators perform node validation work on Ethereum, and the entire process revolves around Ethereum’s existing infrastructure.
• No Autonomous Consensus and P2P Network: Eigen DA nodes re-stake ETH in the EigenLayer contract on Ethereum L1, becoming a subset of Ethereum validators. Through custody proof, each operator must regularly compute and submit a value of a function, only able to compute the value of the function when they store all blob blocks allocated to them within the specified storage period. If they prove blobs without computing this function, anyone with access to their data items can slash the ETH held by the node, ensuring network security and reliability.
• EigenLayer Consensus Mechanism: ETH stakers can choose to validate the Eigen DA network and accept Eigen DA-specific slashing conditions. They then act as POS validators, proving the network state.
• Data Availability Layer: Eigen DA divides data into small chunks and performs erasure coding and KCG polynomial commitments on these chunks to facilitate each node downloading only a small portion of the system, even if half of the nodes leave without affecting the system. They can do this because even if some blocks are lost, the erasure code can rebuild the complete data state, and the KZG proof ensures that the blocks they receive match the blocks declared by the node.

Source: eigenlayer blog

Feature Analysis

• Eigen DA nodes are a subset of re-staking nodes in the EigenLayer network, and becoming an Eigen DA node does not require additional staking costs.
• Existing DA solutions use P2P networks to transmit Blobs, where operators receive Blobs from their peers and then rebroadcast the same Blobs to others. This dramatically limits the achievable DA rate. In EigenDA, dispersers send blobs directly to EigenDA operators. By dispersing data through direct communication, data propagation is no longer limited by the throughput of consensus protocols and P2P networks, thus reducing communication, network latency, and confirmation time and improving data submission speed.
• Eigen DA inherits some of Ethereum’s security and has higher security than other DA solutions.
• Eigen DA also supports Rollup to flexibly select different staking token models, erasure code ratios, etc., providing greater flexibility.
• Since the final confirmation of Eigen DA depends on the Eigen DA contract on the Ethereum mainnet, the cost of Eigen DA is significantly higher than that of other DA solutions in terms of final confirmatory time expenditure.

Eigen DA adopts advanced technologies such as erasure coding, KZG commitments, and ACeD, decoupling data availability (DA) from consensus. This enables Eigen DA to excel in transaction throughput, node load, and DA costs, far surpassing Ethereum’s DA solutions. Compared to other DA solutions, Eigen DA has lower startup and staking costs, faster network communication and data submission speeds, and greater flexibility. Therefore, Eigen DA is poised to become a new contender in the DA market and has the potential to host some of Ethereum’s DA services.

Avail DA

Avail DA aims to address the needs of next-generation trust-minimized applications and sovereign aggregation. Its standout feature lies in its innovative security approach, which allows light clients to easily verify data availability through peer-to-peer network sampling. With Avail DA’s unparalleled data availability interface and robust security features, developers can create blockchain applications based on zero-knowledge or anti-fraud technologies more efficiently and effortlessly.

Source: availproject blog

Analysis of Avail DA

Avail is a blockchain compatible with the Ethereum Virtual Machine (EVM), featuring efficient transaction ordering and recording, data storage, and feasibility verification. Compared to traditional smart contracts and underlying layer dependencies, Avail allows Rollups to directly publish data on it and verify it through a light client network. This modular design allows developers to store data on Avail and choose other networks for settlement, providing more flexibility and options.

Avail’s consensus mechanism inherits the BABE and GRANDPA consensus mechanisms from the Polkadot SDK and adopts Polkadot’s Nominated Proof of Stake (NPoS), supporting up to 1000 validators. In addition to its robust consensus mechanism, Avail also features decentralization, providing efficient and reliable backup mechanisms through light client P2P networks for data sampling, ensuring data availability even during failures.

Avail excels in transaction ordering, recording, and data feasibility verification, supporting EVM-compatible blockchains. Its light client network verification mechanism allows Rollups on Avail to verify states through the light client network without relying on smart contracts and the underlying layer. Due to its modular nature, developers can store data on Avail and choose other networks for settlement.

Type of Nodes

• Full Nodes: These nodes are responsible for downloading and verifying the correctness of blocks but do not participate in the consensus process. Their role is crucial for ensuring the integrity of the network.
• Validator Nodes: These nodes are the core of the Avail DA consensus mechanism. They are responsible for generating blocks, determining included transactions, and maintaining the order of the network. Validator nodes are incentivized through consensus participation and form the basis of operations in the DA layer.
• Light Clients: Operating under limited resources, light clients rely on block headers to participate in the network. They can query full nodes for specific transaction data as needed, which is crucial in maintaining decentralization and network accessibility.

Near DA

On November 8, 2023, the NEAR Foundation announced the launch of the NEAR Data Availability (NEAR DA) layer, providing powerful and cost-effective data availability for ETH rollups and Ethereum developers. The initial users include StarkNet’s Madara, Caldera, Fluent, Vistara, Dymension RollApps, and Movement Labs.

Source: near docs

Technical Architecture

NEAR DA utilizes an integral part of the NEAR consensus mechanism called Nightshade, which parallelizes the network into multiple shards.

Each shard on NEAR generates a small portion of blocks called chunks. These chunks are aggregated to produce blocks. When a block producer processes a receipt, consensus must be reached for the corresponding receipt. Once the block is processed and included in a block, the receipt is no longer needed for consensus and can be removed from the blockchain’s state. Therefore, NEAR does not slow down its consensus speed with more data than necessary, but any user of NEAR DA will have sufficient time to query transaction data. Hence, scalable and cost-effective data availability is crucial for any Rollup solution. As the NEAR protocol transitions to stateless validation, it will further reduce the hardware requirements for certain validators (block validators). By storing the state in memory, NEAR can support more shards, thus increasing the system’s decentralization.

Advantage Analysis

In NEAR DA, consensus validation is provided by NEAR validators, who reach consensus when processing blob submissions. In terms of data persistence, full nodes store functional input data for at least three days, while archival nodes can store data for longer periods.

The design of NEAR DA ensures efficient utilization of consensus without wasting excessive data. Additionally, this data has already been indexed by all major browsers on NEAR to provide support for indexers.

Lastly, for long-term availability commitment, NEAR DA adopts an easily deployable approach, allowing anyone with limited expertise and tools to build commitments.

The NEAR-Polygon CDK integration enables developers to build their Rollups and become part of the Polygon ecosystem. This marks the first integration of NEAR DA with zero-knowledge-based Layer 2 stacks, providing developers seeking scalable data availability solutions with more options.

Conclusion

In the blockchain domain, competition among DA projects such as Celestia, EigenLayer, Avail DA, and NEAR DA is fierce. Despite the proliferation of DA layer projects, their core technologies are not overly complex, with each project boasting unique technical and competitive advantages. These projects showcase the diversity and innovation in the blockchain technology field. In the future, as these projects continue to develop and mature, they are expected to make significant contributions to furthering the growth and development of the blockchain ecosystem.