EVM light client indexer for ao: elciao

EVM light client indexer for ao: elciao

May 02, 2024

A couple of weeks ago, WeaveVM announced EIP-7689 and the specifications for testnet v0 and showed how SmartWeave contracts and MEM functions can live inside WeaveVM (and any network that supports EIP-4844) blobspace. This represents a unification of EVM and Arweave compute layers and shows how WeaveVM can attain broad interoperability between both systems.

Given the rise of ao - a new parallel computer on top of Arweave - we have been working on a way to make the EVM, and WeaveVM by extension, be able to natively talk to ao. The EVM Light Client Indexer for ao (elciao for short) makes it possible for ao to read EVM data by pushing information exposed by a light client to the state of an ao process. In this piece, we’ll get into what this enables and how it works.

What are light clients?

To understand light clients, it helps to contextualize their alternatives: full nodes.

Full nodes require 8-16GB of RAM, at least 2TB of storage, and should have a fast CPU with 4+ cores. A full node processes the last 128 blocks in their entirety, which means downloading all block metadata, transaction history and proofs.

Validating the Ethereum network means running a full node, because they also handle consensus. But in many cases, a full node is overkill if you just need to compute with high-level chain data like block headers and proofs.

Light clients can be run with extremely minimal lightweight hardware, like a low-capacity server or mobile phone.

Their compute, storage, and bandwidth requirements are much lower than that of a full node, and as such they democratize DIY chain validation and are convenient for builders that just need to feed EVM proofs and block metadata to applications.

elciao is built on Lodestar, an open source EVM consensus client written in TypeScript. It was developed to make the Ethereum network validatable by anyone, without a barrier to entry on hardware,and promotes client diversity.

What is elciao?

pronounced ‘el ciao’, like ‘the’ in Spanish and ‘hello’ in Italian. /ɛl ʧaʊ/

elciao is an EVM light client indexer for ao. It works by feeding a constant stream of EVM data (Ethereum, for this proof of concept) to an ao process, storing all future EVM block metadata and proofs on Arweave in perpituity and making that available natively to other ao processes by default. Its architecture comprises:

  • Lodestar for consensus, in optimistic mode
  • Patronum as the RPC proxy server spawned by elciao instances
  • One ao process per elciao node instance to index light client data

What elciao enables

Pushing EVM data to Arweave creates a permanent record of EVM history and exposes that history to dApps built on ao. Permanence of Ethereum history is an unsolved problem, and current bypasses rely on unincentivized archival nodes for storage.

EIP-4444 proposes a system like what we have built, using a storage-focused chain like Arweave as a guarantee that Ethereum data can always be recalled by client apps that need it, like block explorers and API interfaces for RPCs.

Storage guarantees aside, by exposing EVM data to ao elciao makes it so ao processes can verify transactions and smart contract states from EVM chains in a lightweight way, and ensure that data related to state changes, transaction outcomes and other proofs are always available.

Right now, EVM tooling on ao is in its very early stages of development, but once ao processes can call EVM libraries like ethers.js, ao processes can read from an elciao node to:

  • Use a trustless data and assets bridge with Ethereum and other EVMs
  • Trustlessly read data from Ethereum, with availability on ao which can facilitate building highly secure and decentralized wallets and infra

elciao as a decentralized network for EVM data on ao

This release is just the first step for elciao. On the roadmap to come:

elciao v0.1.x the current model, ao used as indexer

elciao v0.2.x implement light client as ao module (no more offchain computation)

elciao v1.x.x a decentralized network of elciao nodes, on ao, based on a PoS consensus model for verified data streams

Follow along

Get the elciao source code on GitHub, and follow the WeaveVM twitter to stay updated as we expand elciao to support the WeaveVM testnet and grow into a decentralized network.