zkEVM Validiums can reduce ETH gas fees by 90%

As Avail nears mainnet launch, this series will explore potential integrations between Avail and leading scaling solutions to showcase how developers can integrate with Avail and take advantage of its secure, decentralized, and low-cost data availability blockchain.

Brief summary:

• zkEVM Validiums can reduce ETH gas fees by 90%.
• Avail provides secure, low-cost, and decentralized block space for data availability.
• Validation of zkEVM Validiums is implemented through smart contracts on ETH Square.
• Avail was spun off from Polygon Labs earlier this year.
• Avail is moving towards mainnet.

zkEVM Validium on Avail

The zkEVM Validium is a new technical framework that significantly reduces the cost of transactions on the zkEVM blockchain. This way to reduce costs is by publishing transaction data to the Avail blockchain, which is specifically designed for data availability, rather than to the ETH.

The Avail blockchain has been designed and built from the ground up as a specialized data availability layer. The Avail blockchain generates and secures the original block space that other blockchains, such as the zkEVM chain, can utilize to meet their data availability needs.

Building a zkEVM Validium with Polygon CDK allows you to benefit from seamless interoperability and shared liquidity within the Polygon ecosystem, as well as leverage future-proof ZK technology to settle on ETH, significantly reducing transaction costs.

How does the zkEVM chain manage data availability?

zkEVM chains built with Polygon CDK have ETH as their default data availability layer. Transactions are sorted, verified, and published to ETH in batches in the form of calldata. Transactions on ETH are expensive, so deciding what data your zkEVM chain will publish to ETH is an important consideration when building a new zkEVM chain. Currently, up to 90% of the cost paid by the zkEVM chain to publish data to the ETH is used for transactional data.

Although some blockchains use ETH as a data availability layer (DA layer), the ETH is not specifically designed as a data availability solution (DA solution). This is one of the main reasons why the cost of using ETH as a data availability layer is relatively high. In contrast, using a blockchain that is specifically designed and built for data availability needs, such as Avail, will cost less.

What is zkEVM Validium?

The zkEVM Validium is an improved version of Polygon’s zkEVM nodes and contracts that uses Avail to manage data availability instead of ETH. This provides a streamlined option for new and existing teams who are building zkEVM chains to manage DA on Avail’s blockchain and benefit from improved economics. zkEVM Validium reduces the amount of data that needs to be published to ETH for up to 90%, significantly reducing the chain’s operational costs and achieving lower transaction fees for end users.

What is Avail?

Avail is a blockchain focused on data availability. Its blocks are designed to provide secure, decentralized, and low-cost block space for the data availability needs of other blockchains, such as the zkEVM chain. Avail also uses proof-of-future ZK technology, which leverages proof of validity to verify that data published to the Avail network is secure and available.

Avail’s nominated proof-of-stake blockchain network is built using the Polkadot SDK to reduce the risk of validator centralization and support up to 1, 000 external validators. The data is published on Avail’s blocks by other blockchains and verified by the Avail network, but not executed.

Avail started as a Polygon project in 2020 and became a separate entity in 2023. Led by Polygon’s co-founder, Anurag Arjun, and former Polygon’s head of research, Prabal Banerjee, the team aims to deliver industry-leading data availability solutions.

How does Avail work?

The data is published onto the Avail blockchain, where it is expanded with erasure coding. This process adds redundancy to Avail-managed data, which makes it more difficult for nodes to suppress or delete any data, making Avail-managed data more secure and robust. Avail then generates two proofs that are used to verify and ensure that the data leaves a footprint in the block header. One is the KZG polynomial commitment of the submitted data, and the other is the “data root”, i.e., the leaf whose leaves are the root of the Merkle tree of the submitted data block.

Once a majority of Avail’s validators agree on a block, it is finalized using a GRANDPA finality gadget. At this point, the availability of the data is guaranteed by Avail. The data root in a confirmed block can be used to prove the inclusion of published data in a confirmed Avail block.

How does zkEVM Validium work?

Just like now, sequencers create batches of transactions, and the batch’s RLP-encoded transaction data is sent to the Avail blockchain before the batch closes.

Here, the data goes through Avail’s standard processing process, including erasure coding and commitment generation. Once Avail’s majority of validators agree on a block, it is finalized. At this point, the data is guaranteed by the Avail blockchain network, providing a soft confirmation. DA containment proofs, including block number, leaf index, tree width, and proof, are sent back to the sequence generator.

The data root is sent from Avail to the ETH via the Vector Data Proof Bridge. This allows the Validium Sequence Generator to verify on the ETH that Avail’s validators have reached a consensus on the availability of the data. Once the sequence sender receives an acknowledgment that the data root for a given batch of transactions has been successfully published to the ETH, the batch can be submitted. The sequence generator submits a proof of inclusion to the ETH.

Below is a simplified diagram showing how the zkEVM Validium works, for a more detailed view check the documentation.

zkEVM Chain vs. zkEVM Validium

The table below highlights the main differences between zkEVM chains and zkEVM validiums. The main difference is that the transaction data of the zkEVM Validium is managed off-chain by the Avail blockchain, thus inheriting the security of the Avail network.

See more:

Build zkEVM Validium now

Polygon CDK provides a way for developers to build highly customizable, scalable, and interoperable layer 2 blockchains that benefit from Polygon’s cutting-edge ZK technology. The zkEVM Validium enables you to do all this while reducing transaction costs.

Start building and testing your zkEVM Validium chain today! If you have any questions, you can join the Avail forums or Discord. To learn more about Avail, check out the Avail documentation and follow us on X.

• Validium node repo：
• contracts：
• Avail Forum：
• Discord：
• Avail Documentation： *X: