Preface

With the rapid development of blockchain technology, monolithic blockchains are facing severe challenges in scalability and interoperability. When mainstream platforms such as Ethereum experience a surge in users, it greatly affects the adoption of decentralized applications, including money laundering and big pump. In response to these issues, developers are constantly seeking innovative solutions, and the emergence of Avail provides a new direction for addressing these problems. After the Cancun upgrade, the transaction cost in the Ethereum ecosystem has significantly dropped, and modular technology has become an important narrative in blockchain development. In the first half of the year, modular blockchains like Celestia and EigenDA led the trend, and Avail also took a critical step in the modular field with the launch of Avail DA Mainnet on July 23rd.

As the core projects of modular blockchain, Avail, EigenDA, and Celestia, although similar in service areas, have their own characteristics in infrastructure, execution mode, and Token economic design.

Team Background

Avail originated from Polygon and became an independent entity in 2023. Before the issue of Data Availability (DA) became a focus in the industry, Anurag Arjun collaborated with others to develop the Plasma chain in an attempt to address Ethereum's scalability issues. Although the chain helped Polygon achieve a revenue of 19 billion US dollars, it failed to become an ideal scaling solution. During this process, Anurag gradually realized that all Blockchains would ultimately face the same obstacles - the issue of data availability. In Rollup Transaction Cost, approximately 80% is related to DA, so he envisioned that building a cost-effective DA layer might solve the scalability issues for multiple Blockchains.

This idea is not unique to Anurag, and most L1 blockchain projects are also trying to become DA layers. Ethereum is exploring DA solutions through the Rollup route, and other L1 projects are also innovating in this area. Anurag believes that L1 blockchains designed specifically for DAs have unique advantages.

During the Matic period, Anurag met Prabal Banerjee, the current co-founder of Avail, who was pursuing a doctoral degree in cryptography and security at the time, and later joined the team as a researcher. The two worked together to build a scalable DA layer. With the rise of Zero-Knowledge Proof (ZK) technology, they combined the blockchain design of validity proof and leveraged Anurag's experience in building a protocol at the billion-level on Polygon to further promote the solution to the data availability problem.

From Single Chain to Modularization

Source: Avail official documentation

With the increasingly fierce competition for underlying computing resources, the issues of single-chain processing, Settlement, sorting, and data availability of ETH block are gradually exposed, leading to limited scalability. The industry is starting to re-examine the single-chain architecture and look for new solutions.

Rollups introduces a modular architecture by moving execution off-chain, effectively relieving the congestion of the L1 network, reducing users' Transaction Cost, and enhancing transaction processing capabilities. Although this architecture significantly improves on-chain efficiency, the limited Block space of Ethereum remains a bottleneck, and this issue may reappear as demand increases. Currently, Dapps rely on L1 for data transmission and Settlement, while Rollups utilize L1 to handle these processes. Despite optimizing the use of Block space, it remains extremely tight.

By analyzing the L1 transactions of ETH Rollups, it is found that DA costs account for 90% of the costs, which is also the largest source of expenses for Rollups, and most of the income is used to pay for the fees of publishing L1 transaction data.

Similar to rollups, Avail moves the execution off-chain, and its architecture enables data availability to be moved to a dedicated layer. Avail provides developers with a flexible, user-friendly, and secure data availability layer, addressing scalability, governance, and decentralization challenges.

Modular structure built by Avail

Avail aims to accelerate the unification of Web3 through its modular technology stack that combines data availability, aggregation, and shared security. Rollups that leverage Avail to publish off-chain transaction data will form Validiums (Optimistic Rollup is called Optimium). Validiums and Sovereign Rollups can rely on Avail's low-trust data availability and ordering services.

Here is a brief process for Avail to support Validiums and Sovereign Rollups:

1. Transaction Submission: Like most existing rollups, transaction invocation data is batch processed, and the state root is submitted to Avail DA with a unique application ID representing the source of the rollup.
2. Data expansion and erasure coding: Transactions submitted to Avail DA are processed through erasure coding, where blocks are divided into n original blocks and expanded to 2n blocks, from which any n blocks can be selected to reconstruct the data.
3. Commitment creation: Avail DA will obtain redundant data and apply KZG polynomial commitment to each Block. These commitments serve as encryption proofs of data integrity, ensuring that the stored data is accurate and cannot be tampered with.
4. Block propagation: validators receive Blocks with KZG commitments and recompute these commitments to verify their accuracy and achieve Consensus on the Block.
5. Light client network: The light client utilizes DAS to verify the integrity of Block data. This is achieved by performing KZG polynomial opening verification on the commitment in each sampled unit of the Block header. This eliminates the need to reconstruct the entire KZG commitment or rely on fraud proof.
6. Proof verification: The light client performs proof verification by generating unit-level proofs from the data matrix.

Since Avail uses validity proof instead of fraud proof, the light client can verify the availability and correctness of the data after the state is finalized. In addition, the light client network ensures the high availability of data through data availability sampling. With more light clients joining, the sampling capability is enhanced, which can support larger-scale blocks. Users can even run these light clients on laptops or mobile phones to further improve network efficiency.

Source: Avail official documentation

Technical Features

The application scenarios of light client

Currently, many application scenarios rely on intermediaries to maintain full nodes, and users indirectly interact with the blockchain through these intermediaries instead of directly accessing it. Due to the lack of data availability guarantees, light clients have not yet become the ideal replacement for traditional architecture. Avail solves this problem, allowing more applications to directly interact with the blockchain network without relying on intermediaries. Although Avail supports full node operations, most applications do not need to run full nodes, or only require a small number of nodes to operate smoothly.

Data Availability Sampling (DAS)

Similar to traditional light client, Avail's light client only needs to download Block header data. In addition, they verify its correctness by sampling part of the Block data's content through random selection. Combined with erasure coding and KZG polynomial commitment, the light client can ensure the data availability almost 100% without relying on fraud proof, and only needs to execute a small number of fixed queries.

Erasure Coding and Data Availability

Erasure coding allows data to be Sharded, so that even if some data is lost, the original content can still be recovered from other Sharding. In Block chain applications, this means that even if malicious actors attempt to conceal some data, the system can still recover the data from other Sharding. This mechanism significantly improves the reliability of data availability sampling and further enhances the ability to prevent data tampering.

KZG Commitment

The KZG commitment technology was proposed by Aniket Kate, Gregory M. Zaverucha, and Ian Goldberg in 2010. It is an efficient polynomial commitment method that has been widely adopted in Zero-Knowledge Proof structures in recent years. In the Avail architecture, KZG commitments have the following advantages:

1. Commit the value in a concise manner and record it in the Block Header;
2. Allowing light client to verify the availability of data;
3. Its encryption binding feature makes it almost impossible to generate incorrect promises, reducing the need for fraud proof.

Avail's Unified Layer

Avail has been building a unified layer for Avail, which is a unified technology stack starting from the basic Data Availability (DA) layer, the Nexus unified layer, and the additional security layer Fusion. Avail will support the entire Web3 ecosystem through an scalable Data Availability layer, utilizing validity proof using KZG polynomial commitment to ensure instant and reliable data availability, enabling aggregation to rise, connect, stay secure, and adapt.

Avail DA

Source: Avail official documentation

Avail DA is a bottom-up architecture designed specifically for data availability optimization, employing the GRANDPA and BABE Consensus Algorithm, distinguishing it from other DA layers. This design enables Avail DA to have high scalability, ensuring reliable data protection at low cost through data availability sampling (DAS) and validity proof.

The core of Avail DA is the priority sorting and publication of transactions, while allowing users to verify the availability of Block data without downloading the entire Block. The data independence of Avail DA is one of its defining features. It supports various execution environments, including EVM, WASM, and custom new runtimes, providing a versatile foundation for various blockchain applications.

Avail Nexus

Source: Avail official documentation

Avail Nexus, as the second pillar, is a permissionless framework designed to unify the web3 ecosystem. It connects internal and external blockchains, relies on Avail DA as the trust base, and acts as a verification center. Nexus includes ZK-coordinated Rollup, integrating proof aggregation, verification layer, sequencer selection mechanism, and slot auction mechanism. Nexus regularly submits aggregated proofs to Ethereum and Avail DA layer for verification, ensuring the reliability of Cross-Chain Interaction operations.

Avail Fusion

Source: Avail official documentation

The third pillar, Avail Fusion, provides additional security for the Avail ecosystem and the entire web3. Its core concept is that a unified system requires unified security at the macroeconomic level. Fusion Security contributes security to Avail Consensus by leveraging native assets in mature ecosystems such as BTC and ETH. This mechanism is the first attempt to achieve consensus across different blocks on-chain through external tokens.

Avail Fusion supports two types of assets stake: mature Cryptocurrency and emerging Rollup Token. Currently, Fusion's prototype consists of two stake modules: one executed on Avail Block on-chain and the other is the asset conversion stake module. It should be noted that the first public prototype of Avail Fusion is still under development.

Node type of Avail

Although Avail's architecture is different from traditional monolithic blockchains, it also supports various types of Nodes, including Full Node, light client, Archive Node, and Validation Node.

• Full Node: Full Nodes are responsible for downloading and verifying the correctness of Blocks, but they do not participate in the Consensus process. Their existence provides additional redundancy and resilience to the system, but they are not a necessary component.
• Verification Node: The verification Node generates Blocks, determines whether transactions are included, and maintains the transaction order to help the network achieve Consensus.
• light client: A light client allows users to interact with Avail's data availability layer (DA) without running a Full Node or trusting remote peer Nodes. They achieve this by performing Data Availability Sampling (DAS) on every newly created Block.
• RPC Node: RPC Node provides an API for remote interaction, serving as a gateway for developers and external users to access the Avail network.

The light client will listen to the confirmed Blocks on the Avail network and perform Data Availability Sampling (DAS) on the predetermined data units of the new Blocks. After successful verification, the system calculates the determinism of a certain number of data units in the Block based on the desired confidence level of the user.

Economic Model

Token Allocation

With the release of AvailDA Mainnet, the team Airdropped AVAIL Tokens to eligible users with a total supply of 10 billion. Among them, 6% is used for Airdrop and public distribution, 30% is used for ecosystem development, 23.88% is used for community and research, 14.12% is allocated to investors, and 20% is allocated to core contributors.

Source: Avail official documentation

stake

The use of AVAIL Token covers ecosystem governance and Liquidity stake. Although the official governance plan has not been detailed yet, anyone can stake AVAIL throughout Avail's entire infrastructure to obtain stake rewards.

In terms of stake, Avail adopts the Nominated Proof of Stake (NPoS) Consensus Mechanism inherited from the Substrate ecosystem. Stake plays a crucial role in NPoS. By staking AVAIL Tokens, users help to enhance network security and receive corresponding rewards. The more tokens staked, the higher the network's security, as the cost of attacking the network also rises.

The application scenarios of stake are as follows:

• Avail DA stake: Users can stake AVAIL Tokens to validators or nomination pools to ensure network security and support different use cases, such as Web3 games and Decentralized Finance platforms. Stakers can receive rewards.
• Avail Nexus stake: Sorters need to stake AVAIL Token to participate in transaction submission and sorting. Sorters with excellent performance will be rewarded, while those with poor performance will be penalized.
• Avail Fusion stake: In addition to AVAIL Token, you can also stake other mainstream encryption assets such as BTC and ETH to further enhance network security. Stakeholders can receive corresponding returns.

It should be noted that if users want to unstake, they need to complete a 28-day unbonding process, during which AVAIL Token cannot be used or transferred.

Facing Challenges

Rollup Competitive Risks

The development of Avail may be influenced by large-scale general rollups, which have mature ecosystems and internal interoperability solutions, which may no longer rely on external interoperability systems, thereby weakening the value of Avail Nexus. However, the rapid increase in the number of application-specific rollups and the highly fragmented problems faced by users make this situation unlikely to occur.

Competition of DA Solution

With the introduction of various DA solutions in the market, such as Celestia and EigenDA, Ethereum has also introduced blobs as a data publishing option through EIP-4844. The fierce competition between the DA layers and the sensitivity of rollup to the data publishing cost may drop, thereby prompting rollup to prefer verified DA solutions or rely on them for data publishing after the comprehensive implementation of danksharding on Ethereum.

Shared security risks

The shared security model provided by Avail Fusion relies on the staking of multiple Tokens and AVAIL Token, which may lead to concerns about the security of multiple assets for users. Some developers may prefer to secure a single asset (such as ETH or BTC) rather than rely on multiple Tokens. In addition, if Avail Fusion fails to provide sufficient security, developers may turn to DA solutions with stronger economic security.

Competition in the value-added service ecosystem

Other staking or sharing security products may have a value-added service ecosystem specifically tailored to rollups. For example, EigenLayer may offer Decentralization sorting, data availability, and fast finality functions, which will enhance its competitiveness.