Modular Blockchains the Next Alpha? Celestia Overview
Celestia is a pluggable consensus and data availability layer that enables anyone to deploy a decentralized blockchain quickly.
Celestia, formerly LazyLedger, is the First Modular Blockchain Network. It is a pluggable consensus and data availability layer that enables anyone to deploy a decentralized blockchain quickly without the overhead of bootstrapping a new consensus network. In an interview with Nick White of Celestia, he explains that Celestia is a sort of cloud computing for Web 3.
In Web 2, cloud services, such as Amazon Web Services, enabled users to launch websites on virtual machines that share physical machines (physical servers). Celestia enables users to launch decentralized applications on app-specific chains that share a consensus layer.
The problem with monolithic blockchains, L2 scaling solutions, and EVM
There are already scaling solutions such as Optimism, ZKsync, and Starknet. However, data availability on these scaling solutions is reliant on Ethereum. The bad news is that Ethereum is still expensive, explaining why gas fees on L2s can be high.
The Ethereum Virtual Machine (EVM) is limited in what developers can deploy, and the gas fees are high. Developers cannot build complicated applications that the EVM does not support unless you develop a blockchain with something like Tendermint.
There is a considerable overhead associated with creating a blockchain. Developers must create a consensus layer (typically proof of stake) and launch a token sale. Celestia saves builders from all this hassle.
Most of the blockchains today are monolithic. The core functions of a blockchain, execution and consensus, happen simultaneously and are enforced by the same set of validators. A monolithic architecture is hard to scale because every transaction has to be executed by the full node, causing a bottleneck.
How Celestia works
Celestia applies modular architecture, which decouples a blockchain stack into specialized components. The core functions, consensus and execution, are separated into different layers.
A monolithic architecture can be limiting. The consensus and execution functions are bundled into one layer, and a smart contract is then built on this bundled layer. Users are bound within one execution environment, limiting the potential to optimize and specialize for specific use cases.
A modular architecture separates the consensus and execution into separate layers. The execution layer exists on its own blockchain, allowing for optimization and specialization for specific use cases. Any developer building decentralized applications built on this architecture will enjoy better flexibility, security, and scalability.
In a modular blockchain, data availability sampling is achievable, enabling a node to verify a block with a tiny sample, such as verifying a 100MB block with only 10KB of data. A machine with minimal processing power, like a smartphone, can act as a node.
When developers build dApps on Celestia directly, they can choose the execution environment to use and run as many execution environments as they want in parallel. In a monolithic environment, the consensus binds the execution rules tightly, meaning users are bound to whatever execution environment the base chain supports.
In the future, we are likely to see Tendermint chains and Cosmos zones using Celestia as a data availability layer. These zones will become trust-minimized by utilizing fraud proofs to give the Cosmos ecosystem a uniform level of security and help reduce its reliance on social governance when dealing with bad zones.
Devnet was launched in December 2021 with three major components; Optimint, Celestia-app, and Celestia-node.
The Celestia-node component is tasked with consensus and networking for this blockchain. This component determines how light and full nodes make new blocks, sample data from blocks, and sync new blocks and block headers.
With Optimint, a Cosmos zone deploys directly on Celestia as a rollup. This software spins up a peer-to-peer network, collects transactions into blocks, and then posts them to Celestia for data availability and consensus.
The state machine for the chain lives on the Celestia app. It is the app that handles transaction processing and staking.
The devnet is not finished as the team will still work on various features before testnet. On Optimint, there will be improvements on syncing blocks, data availability layer integration, general tooling, and indexing transactions. In the Celestia app, the team will work on the implementation of transaction fees and also evaluate an upgrade to ABCI++. Finally, the team wishes to make its networking services more robust on the Celestia node and polish the light node and bad encoding fraud proofs.
Creating a modular world demands more than scalable data availability layers like Celestia. It also requires the creation of cross-rollup bridges, new execution layers, and developer tooling. Teams already working on scalable execution layers include Offchain Labs, Optimism, Fuel, Matter Labs, and StarkWare. On the other hand, there are teams creating bridges to connect execution layers: Connext, Composable, and Axelar.
Quantum Gravity Bridge
Celestium is an Ethereum Layer 2 chain that uses Ethereum for settlement and dispute resolution but Celestia for data availability. It is worth noting that Celestia does not handle computation and is only a data layer. Celestia has a cost advantage as its pricing is based on bytes and not on storage and computing. Celestia thus handles the availability and ordering of transactional data, which makes its throughput better than Ethereum’s.
The Quantum Gravity Bridge will sit on Ethereum, and various Layer 2 operators will post their transactional data on the Celestia network. The proof of stake validators will place this data into blocks. Then, the data will be relayed from Celestia to Ethereum in the form of a data availability attestation.
The work of the Quantum Gravity Bridge contract is to verify all the signatures on the data availability attestation from Celestia. When a Layer 2 contract on Ethereum updates its state, it will query the DA bridge contract instead of relying on transactional data posted as call data to Ethereum. The bridge would relay a positive response if a valid attestation was relayed to it previously.
Mustafa Al-Bassam, CEO, Celestia Labs, holds a Ph.D. in blockchain scaling at UCL. He previously co-founded Chainspace, a sharded smart contract platform that Facebook later acquired. Mustafa has also written several seminal papers on the security of sharded blockchain systems.
John Adler, CRO, Celestia Labs, is a researcher on Layer 2 scalability. He was previously at ConsenSys, working on Phase 2 of Ethereum 2.0. Drawing inspiration from Mustafa’s works on data availability, Adler created the first specification for an optimistic rollup scheme.
Ismail Khoffi, CTO, Celestia Labs, is an established research engineer with years of experience. On top of building academic research prototypes, he has also contributed to bringing various non-blockchain and blockchain projects such as Google UK and Tendermint to production.
Nick White, COO, Celestia Labs, holds BS & MS from Stanford. Before joining Celestia, Nick White co-founded Harmony, a blockchain protocol building scalable blockchain infrastructure to power the decentralization revolution. White worked there from June 2018 to December 2020. He was also a senior AI specialist at Zeroth.ai, an accelerator program for AI startups in Asia.
Celestia is still in the early stages of development. The development team released an MVP in 2021 and a devnet in November 2021. 2022 will be even more significant as the project will launch a testnet and build the Mainnet gradually.
Scalability has been one of the biggest barriers to the full adoption of blockchain technology. Even though a couple of Layer 1 scaling solutions exist, most focus on block production and not block verification. With its scalability, security, and decentralization features, the First Modular Blockchain Network, Celestia, is preparing us for Web 3. Celestia is not the only solution as Polygon has Avail and Ethereum has Danksharding. However, Celestia is unique as it focuses on ease of integration, fast delivery, and user experience.