📄️ System Overview
We have made a proposal to the Optimism ecosystem and implemented "forkless rollup" by integrating the Babylon Bitcoin staking into OP Stack.
📄️ Finality Provider
Finality provider is a daemon program that receives delegations from BTC stakers and keeps submitting finality signatures over the rollup blocks to the finality contract on Babylon.
📄️ Finality Contract
Finality contract is a CosmWasm smart contract that maintains all finality signatures submitted from OP-stack finality providers.
📄️ Finality Gadget
Finality gadget is a daemon program that keeps tallying all finality signatures for L2 blocks and serves RPC to allow querying the BTC-voting quorum of those blocks.
📄️ OP node with finality gadget
This is a modified OP node that enforces BTC-voting quorum before finalizing L2 blocks.
📄️ Case study: fast finality
To understand why BTC staking can solve these two problems, let’s consider an example where Alice sends an L2 transaction to Bob, and Bob can quickly confirm the transaction without worrying about double-spending.