Guide to Brevis
July 31, 2024
We are excited to announce that the Brevis ZK Coprocessor AVS is live on our EigenLayer Operator. If you’ve restaked ETH or LSTs on EigenLayer, visit our Delegation Guide to delegate to Coinbase’s Operator.
Introduction to Brevis
Brevis is a ZK coprocessor that gives smart contracts the ability to read historical onchain data from supported blockchains to run customizable computations trustlessly. This enables developers to build a range of data-driven dapp features like intent-based active liquidity management, loyalty trading programs, and account reputation systems.
How it works
Dapp developers will need to implement three things using the Brevis SDK:
Data Access Module: Specifies the needed historical blockchain data
App Circuit: Specifies computation logic to run on historical blockchain data
App Contract: Receives and processes ZK-verified computation results
Source: Brevis Docs
The App Service receives input from users or operators
The App Service obtains data based on the dapp’s business logic. This data comes from an offchain indexing solution
A ZK proof is generated to show that both the computation of business logic and the onchain data retrieved from the indexer are valid
The App Circuit proof generation is hosted by the App Service
The onchain data proof generation is hosted by the Brevis Service
The Brevis Service will combine the two proofs into one
The computation results and combined ZK proof will be verified onchain by the Brevis Contracts
It is expected in the future that the App Circuit and the Brevis Service will be migrated to a decentralized prover network and Brevis coChain.
Brevis coChain
Before coChain, Brevis ZK proofs for data access and computation results were always generated upfront. Dapps could only use these results after onchain verification of the ZK proofs. This model has some drawbacks, more specifically on high proof generation costs and the lack of ability to generate proofs in specific use cases. An example would be to try to generate a proof of non-existence.
The Brevis coChain introduces a propose-challenge architecture to address these issues. Here, a proposer can generate and submit coprocessing results onchain without completing the entire ZK Proof computation. After this, a challenge window defined by the developer begins. In the duration of the challenge window, any observer on the chain can initiate a challenge submitting a ZK proof that challenges the initial claim. Successful challenges result in penalties for the proposer and the challenger receives the reward. If no challenges happen during this period, then the dapp considers the results valid.
Source: Brevis Blog
The Brevis coChain is a Proof of Stake blockchain in which, upon receiving a coprocessing request, validators within the chain generate coprocessing results based on the data from the specified blockchain’s archival nodes. Upon consensus, Brevis coChain pushes the results to the requesting blockchain in the form of a proposal.
This proposal initiates two timers: a dapp challenge window and a coChain slashing window. Anyone can then challenge a result by submitting a challenge claim with a bond onchain. A successful challenge triggers an onchain slashing contract penalizing malicious validators and rewarding the challenger. If the challenge fails, the bond is forfeited.
For a specific use case, please refer to Brevis’ Uniswap V4 Hook + Brevis SDK Coprocessor Blog Post
Conclusion
The Brevis ZK Coprocessor AVS empowers developers to build innovative, data-driven dapp features by enabling smart contracts to read historical onchain data and perform customizable computations trustlessly. The Brevis architecture, enhanced by the upcoming decentralized prover network and Brevis coChain, ensures efficient and secure zero-knowledge proof validations. As part of our commitment to advancing blockchain technology, Coinbase proudly supports Brevis through EigenLayer. For delegation details, please refer to our delegation guide or contact us today.
Disclaimer
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