PSE Trading: New Narrative of Block Chain - DA Layer Competing for the Champions

Original post by @cryptohawk, PSE Trading Analyst

1. An integral part of the modular blockchain

The historical mainstream blockchain architecture is a non-hierarchical structure, that is, the four core functions of calculation/settlement/consensus/data availability are performed by the same batch of nodes. On the contrary, the hierarchical structure of the blockchain, the node only needs to focus on a part of the four core functions of computing/settlement/consensus/data availability, thereby reducing the node hardware threshold and achieving expansion.

The definition of the four core functional modules of the blockchain:

At the moment when the Ethereum Rollups ecology with Ethereum as the core is in full swing, the gas fee of L2 can save nearly 90% compared with L1, but it is still not low enough, and there is still a distance from the goal of connecting hundreds of millions of C-end users envisioned in the future.

According to the speech of the founder of Avail at the 23.7 ETH Community Conference, nearly 70% of the cost of Rollups currently lies in the release of tx data & proof data on Ethereum L1. The next step for modular blockchains is almost foreseeable, with ETH L1 and numerous dedicated DA layers competing at the level of data availability to dramatically lower the barrier to entry for new rollups, further strengthening the zone without sacrificing security and decentralization Blockchain scalability & reduced interaction costs.

2 DA LAYER LATEST DEVELOPMENTS

2.1 DA layer technology path

Regarding how to ensure the availability of data, the DA layer adopts many technological innovations, and some technical directions have been agreed by the DA layer, such as ensuring that complete data can be obtained/restored:

(1) Erasure code

In order to prevent DA nodes from losing data fragments, the erasure code technology expands the original data from N elements to M elements (M > N), as long as any N unique elements are obtained from the M elements of the extended data, the complete extended data.

The DA layer uses tx/blob in the block as the smallest element, EigenDA & Espreeso adopts a one-dimensional Reed-Solomon coding scheme, and Celestia & ETH Darksharding adopts a two-dimensional Reed-Solomon coding scheme.

(2) Data availability sampling

The data availability sampling mechanism is based on erasure codes, that is, nodes do not need to download complete block data, and a certain number of data blocks are randomly sampled from block builders through sufficient nodes (even light nodes) to ensure the most In the worst case full blocks can be recovered.

Of course, in other technical directions, such as how to prove that the original data has been correctly coded and expanded, there are differences in the schemes adopted by different DA layers:

(1) Fraud Proof Mode

Representative project: Celestia

Through the light nodes sampling enough unique data blocks and broadcasting to the full nodes, the honest full nodes can execute the encoding to restore the complete block, and recalculate the Data Merkle Root and the Root released by the block builder for comparison and verification. If the verification fails, that is, it proves that the original data has not been correctly encoded and expanded, the full node will broadcast the fraud proof to the light node & full node.

Advantages: The technical barriers to the implementation of the game theory incentive mechanism are smaller;

Disadvantage: Minimal honesty assumption needs to be met.

(2) KZG Commitment Model

Representative projects: EigenDA, Espresso, Avail, ETH Darksharding

KZG commitment is a polynomial commitment proof. According to the tx data specification of the DA layer, all original data and extended data are mapped to the X, Y grid, as shown in the figure below with 8 elements (d 0, x 0), (d 1, x 1)…(e 0, x 4),(e 1, x 5)…, and then use Lagrangian interpolation to find the minimum order polynomial that runs through them. Prover needs to match this polynomial f(x) with a secret A trusted setting of , makes a commitment C(f).

Subsequently, Prover will generate a fixed 48-byte proof Π for the group elements. With C(f), the verifier can verify whether y=f(x) holds for each element, provided that all original data and extended data The element points of are all on the same polynomial, it can prove that the original data has been correctly coded and expanded.

Advantages: fast verification and proof;

Disadvantages: Trusted settings are required in advance & not resistant to quantum computing.

(3) DA committee multi-signature mode (Data Availability Committee)

Representative project: Arbitrum Nova

In this mode, the blockchain relies on an external DA committee to store tx data and promises to provide data according to the needs of B-end/C-end users. The so-called DA commitment means that the committee members can sign the Hash & DA expiration time of a certain tx data block with a BLS signature that meets a certain number of thresholds.

Advantages: extremely low cost;

Disadvantages: Data availability also depends on the matching honesty incentive model + evil punishment model + DAO governance model, the reliability is lower than fraud proof & KZG commitment proof, so it is suitable for interactive tx data storage of non-financial applications with low value.

2.2 Module division scheme

There are also many design schemes on the market for how different modules of the blockchain are divided between specific projects. The following lists six mainstream design frameworks: Celestium, Celestia Sovereign Rollup, Eigen Rollup, Espresso Rollup, and Ethereum Rollup.

Throw out a few core points:

(1) The unified settlement layer can enable many Rollups to enjoy cross-chain security & aggregate liquidity.

Compared with the cross-chain between L1 through the relay trust layer, the unified settlement layer between Rollups can share the global state between each other in real time at the settlement layer, and the security of token & information cross-chain is higher.

The following author lists two third-party cross-chain bridge solutions:

• Through the official cross-chain bridge contract & SDK under Rollups, the cross-chain without the assumption of greater trust is realized;

• Realize faster and lower cost cross-chain through third-party liquidity pool.

(2) The tx sorting right should not be undertaken by the DA layer.

Recently, Celestia researcher NashQ proposed a variety of Rollup variant modules, in which the tx sorting right is mainly assigned to the aggregator/DA layer. The author believes that more and more attention has been paid to the discussion on the democratized distribution of mev. The mechanism represented by PBS can reasonably distribute the value of mev among arbitrageurs & nodes/sorters, and will be adopted by the head Rollup with a high probability. The design of the consensus mechanism and network architecture of the DA layer should focus on the guarantee of data availability. If an additional mev allocation mechanism related to tx sorting is added, it may pose unnecessary challenges to the technical requirements of the network architecture.

(3) In the next ten years, Ethereum will still be the best option for most Rollup consensus layers & settlement layers.

Under the modular blockchain framework, most blockchain users (even practitioners) don’t care much about the security & block finality provided by the consensus layer, and the author believes that the consensus layer is the core of the blockchain module. The most important part is that even in 2023, there was an abnormal block rollback event of the Polygon POS chain, which greatly extended the block confirmation time of the Cex & cross-chain protocol for the Polygon POS chain, which had a negative and far-reaching impact. Therefore, the author judges that Ethereum will be unshakable as the leader of the consensus layer of the smart contract public chain (91 Open) in the next ten years, and it is also the best option for the Rollup consensus layer. As the key module of Rollup block & global state settlement confirmation, the settlement layer is the best choice to unify with the consensus layer.

3 Introduction to mainstream DA layer projects

3.1 Celestia

As the first solution to provide a DA layer, Celestia’s network architecture is divided into a consensus layer and a data availability layer.

(1) Consensus layer: Celestia borrows heavily from the architecture of Cosmos, and builds a POS chain named Celestia APP as the consensus layer, under which Celestia-core uses the modified version of Tendermint as the consensus algorithm, and the nodes still use Tendermint p2p network rules, and connect to the application layer (ie state machine) through ABCI++ to execute PoS logic and perform governance.

(2) Data Availability Layer: Celestia uses Data Availability Sampling (DAS) technology to allow light nodes to generate security attributes close to full nodes by downloading only the block header containing the Merkle root of the block data without downloading the complete block.

Specifically, in each round of DAS, Celestia light nodes will sample the 2 k × 2 k data blocks encoded by erasure codes for each block. Each light node randomly selects a set of coordinates in the expansion matrix, and queries the full node for the data block and the corresponding Merkle proofs at these coordinates.

Assuming that the full node hides the tx when broadcasting a block containing 1000 tx, the assumption that the light node is required to be available for all block data through sampling inspection (that is, no error/lost data block that is not enough to recover the complete block) is reached 99.9999% confidence probability, if a simple sampling of 1000 original data blocks & a malicious full node hides a tx, it will take about 13,800 samples to achieve it, it is better to download the complete block directly; Data blocks are sampled & malicious full nodes hide more than 1 million data blocks, only 48 samples are needed, and the efficiency difference is about 288 times.

What DAS can achieve:

1. A small amount of sampling can find out whether the block broadcast by the full node hides more than 25% of the block data;

2. Sampling to obtain 75% of the data can ensure that the complete block data can be recovered.

What DAS cannot achieve:

1. If the block producer hides more than 25% of the data, it may not be possible to recover the complete block data;

2. If there are not enough light nodes to sample, it may not be possible to sample enough non-duplicated data blocks to reconstruct the entire block.

For in-depth research reports, see:

3.2 EigenDA

EigenDA, as the first AVS network officially developed by EigenLayer, belongs to EigenLayer’s “pro-son” and is positioned at the DA layer of the security subset of Ethereum.

Founder Sreeram Kannan conducted innovative research on Coded Merkle Tree, Scalable Data Availability Oracle, DispersedLedger and other technologies on DA, and currently uses block data 2 times redundant one-dimensional erasure code + KZG commitment + Authenticated Coded Dispersal (ACeD ) single-node storage 1/n data block (network node number n) technical framework, hoping to greatly achieve Danksharding, the final DA solution of ETH, in terms of DA efficiency and node bandwidth.

For in-depth research reports, see:

3.3 Espresso

The Espresso Sequencer network chooses to separate the DA layer and the consensus layer in a modular manner under the same node set. The DA layer is responsible for screening & sorting tx+ to ensure data availability, and the consensus layer is only responsible for reaching an agreement on the short commitment of the data set. In addition, the DA layer and the consensus layer will also lease/share the security of ETH through a re-staking layer such as EigenLayer.

advantage:

(1) Flexibility: Under optimistic conditions, the CDN & small DA committee can greatly improve the data transmission capacity & block confirmation speed of the network. Under pessimistic conditions, the network can also switch to the P2P protocol & DA base layer in time to ensure security;

shortcoming:

(1) Architecture redundancy: the Espresso Sequencer consensus layer does not need to be separated from the DA layer at all;

(2) The network security is almost equal to the amount of ETH re-staked by EigenLayer in the Espresso Sequencer network, and there is a risk that EigenLayer’s resources tend to be pro-son under the competitive situation with EigenDA on the same track;

(3) The MEV capture capability & transaction review right is completely concentrated on Tiramisu, that is, the Espresso DA layer, which needs to be connected to PBS solutions for optimization in the future.

For in-depth research reports, see:

3.4 ETH Proto-Darksharding

In the future roadmap of Ethereum shown by Vitalik on 22.11.5, it clearly shows that after The Merge: POW to POS stage, the key goal of the next stage of Ethereum is to further improve transaction performance for Rollups through EIP 4844. The entire Ethereum is positioned as DA&consensus&settlement layer, and only the execution layer is assigned to Rollups.

EIP 4844 is expected to be launched in the Cancun upgrade at the end of the year. This EIP introduces a new transaction type, namely blob-carrying transaction. The tx data uploaded by Rollup can be stored non-permanently on ETH Layer 1 in the form of blob. The size of a single blob is 128 KB, and each block ideally contains 8 blobs, with a size of about 1 MB, and a maximum of 16 blobs, with a size of about 2 MB, which is a huge improvement compared to the current average block size of 90 KB in ETH. special expansion. In order to prevent the explosion of the storage status of ETH nodes, it is planned to automatically delete the blobs outside the period of time (the specific time window is undecided, it may be 2 weeks or 1 month), so the blob can be regarded as a kind of cache.

Although the future finality envisaged by Vitalik only stores the state root on the Ethereum chain, and the detailed transaction data is stored on the dedicated DA layer, the short-term compromise solution EIP 4844 will point to the direct connection between the ETH chain and the dedicated DA layer. Business competition, in addition to playing the “lower data storage cost” card for the dedicated DA layer, whether it can explore a broader business model and build a better DAPP ecosystem will be the key to success.

4 Conclusion

In the past round of cycles, the entire pan-data storage track did not have an advantage in the accumulation of capital bubbles and attractiveness to developers, or because users were not sensitive to the risks of centralized data storage & hosting, and decentralized The need for storage is temporarily falsified. The DA layer, as an indispensable module in the modular blockchain, is positioned at the storage of the most valuable execution layer transaction tx data, and ensures the availability of data at a lower cost (public access without access & anti-censorship ) & Integrity & Correctness & Privacy will be a narrative with more commercial needs.

In the short-to-medium term, the DA-level track will be divided into groups.

(1) Ethereum Rollup will benefit from the reduction in blob data storage costs brought about by EIP 4844 after the Cancun upgrade, or will continue to maintain the market competitiveness of ETH L1 in the DA module;

(2) Optimistic about DA layer solutions (such as Celestium) that use ETH L1 as the settlement layer, and bring better “Lego building block” interoperability between the execution layers by enabling the execution layer to share cross-chain security/liquidity , conducive to a virtuous circle of ecological development;

(3) Optimistic about DA layer solutions (such as EigenDA, Espresso) relying on the EigenLayer heavy pledge agreement, which can not only reduce the cost of tx data storage, but also share part of the security of ETH L1;

(4) The shared sorter scheme with a good incentive distribution mechanism (such as PBS) will be adopted by the head Rollup execution layer. The tx screening/sorting right should not be given to the DA layer, and the DA layer should concentrate on the task of making data available.

References:

2.‘Unpacking Celestia’，from Analyst DAO

3.‘Pay Attention To Celestia’, by Can Gurel, from Delphi Digital

4.‘State of Modular Blockchains’, by Roy Lu

5.‘Fraud and Data Availability Proofs: Maximising Light Client Security and Scaling Blockchains with Dishonest Majorities’, by Mustafa Al-Bassam, Alberto Sonnino, and Vitalik Buterin

6.Data availability sampling and danksharding: An overview and a proposal for improvements，by Valeria Nikolaenko and Dan Boneh

7.Exploring MEV on EigenLayer，by Walt Smith

8.Hack Summit 2023 How to build new VMs and rollups using eigenDA

9.EigenLayer: The Restaking Collective，by EigenLayer Team

10.Don’t overload Ethereum’s consensus

13. Detailed Explanation of HotStuff Consensus Algorithm

14.The Hitchhiker’s Guide to Ethereum, by Jon Charbonneau

Original link