Cosmos Avail DA module

What is CADA (Cosmos Avail DA module)

CADA is a module designed to connect Cosmos sovereign chains with the Avail network, making it easier for any Cosmos chain or rollapp to use Avail as their Data Availability (DA) layer.

With CADA, developers can improve the scalability and security of their decentralized applications within the Cosmos ecosystem. It enables better data handling and availability, allowing Cosmos-based chains to tap into the strengths of Avail and build a more connected and resilient blockchain network.

Learn more about the CADA module below:

What is Avail DA?

Avail is the permisionless unification layer for web3. Avail is designed to be a platform that connects different ecosystems by providing a modular, scalable, and interoperable platform. Avail's vision is to provide a cohesive, unified user experience within a flexible and modular blockchain ecosystem, drawing on lessons from Web2 to innovate in Web3.

With Avail's foundational DA layer (Avail DA), different ecosystems can innovate on top freely, while leveraging Nexus for cross-ecosystem messaging.

Learn more about Avail here.

Integration Guide

To integrate the CADA module into your Cosmos SDK application, follow the steps outlined in the integration guide (opens in a new tab)

You can also use the references below for integration.You can also simply run the module from these repositories as well:

If you are running the chain from the Simapp repository, you can use this init-chain script (opens in a new tab) to set up the testnet.

How It Works

These are main components in the workflow:

1. CADA

The core functionality of the CADA module is integrated with and operates on the Cosmos blockchain.

In the CADA module:

• At each block interval, the PreBlocker ABCI method sends a request to the Relayer, specifying the range of block heights that are ready to be posted to the Avail Data Availability (DA) network.

• The chain is responsible for aggregating vote extensions from all validators and verifying whether the data has been made available on Avail.
• Since verification requires communicating with the light client, an asynchronous voting mechanism is needed. Vote extensions enable this asynchronous voting mechanism for verification purposes.

2. Relayer

The Relayer facilitates communication between the Cosmos Chain, the Avail light client, and the Cosmos Provider.

• Data Submission: The relayer is responsible for fetching block data from the Cosmos provider and posting it to the Avail light client via an HTTP request.

• Based on the response from the light client, the relayer submits a transaction informing the validators of the data availability status and the specific Avail block height where the data is included, so that validators can verify it.

• Data Verification: During verification, the relayer communicates with the Avail light client to confirm whether the data is truly available at the specified height.

3. Avail Light Node

The Avail Light Client allows interaction with the Avail DA network without requiring a full node, and without having to trust remote peers. It leverages Data Availability Sampling (DAS), which the light client performs on every newly created block.

• The chain communicates with the Avail light client via the relayer during the data submission and data availability verification processes.

Find more details about the Avail Light Client here (opens in a new tab).

4. Cosmos Provider

The Cosmos Provider is responsible for fetching block data via RPC so that the data can be posted to Avail for availability checks.

Workflow

• At each block interval, a request is sent from the PreBlocker ABCI method to the Keeper, specifying the range of block heights that are ready to be posted to the Avail DA network.

• The range of block heights should be from provenHeight + 1 to min(provenHeight + MaxBlocksLimitForBlob, CurrentBlockHeight).

• If the status of the previous blocks is either SUCCESS or FAILURE, the status can be updated to PENDING.

  range = [fromBlock, toBlock] // (fromBlock < toBlock < CurrentBlock)
  status = PENDING

• The Proposer of the block will make a request to the Relayer to post the blocks data by passing the range of blocks to be posted.

• The Relayer fetches the blocks data from the local provider, converts the blocks data to bytes, and posts that data to Avail.

• Once the success of data availability is confirmed, the Relayer broadcasts the Avail height at which the blob data is made available using the MsgUpdateBlobStatus transaction.

• The status, Avail height, and voting deadline will be updated in the state.

  status = IN_VOTING
  availHeight = tx.availHeight
  votingEndBlock = currentBlock + votingInterval

• At block height VotingEndBlock - 1, all the validators verify if the specified blocks data is truly made available at the specified Avail height. They cast their vote (YES or NO) using vote extensions.

• At block height VotingEndBlock, all the votes from vote_extensions will be collected and aggregated. If the collective voting power is > 66%, the status will be updated

  status = SUCCESS // success and ready for next blocks
  provenHeight = Range EndHeight // End Height from the given block range
  

• In case of failure at any stage, the whole flow will be repeated.