Challenges
Build with Bitcoin
we are using bitcoin P2TR spends to post calldata
Most Useful Web3 Tool
Adding additional support for non EVM based rpcs to OP stack. We also have a bticoin SPV relay (though not hooked up) that is a nice alternative to the non opensource ones currently out there.
#BUIDLathon 2023 Infrastructure + Scalability
bitcoin as DA is pretty funny and was theoretically scalable before ordinals
Project details
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Data Availability (DA) is an important factor differentiating Rollups from other scaling approaches (Plasma Chains, State Channels, etc.). Up to this point, the most popular Rollups have opted to using Ethereum as their DA layer. However, using Ethereum as a DA layer can be quite expensive. An interesting alternative has unexpectedly resurfaced: Bitcoin. With its Taproot upgrade the amount of data that was feasible to commit on-chain increased, spawning the Ordinals project, inscribing the full image data for NFTs on the Bitcoin blockchain and tying them to individual sats (satoshis, the smallest directly divisible unit of Bitcoin).
Bitcoin is an interesting DA layer because, like Ethereum, it's very decentralized and secure. Depending on the day-to-day demand posting data to Bitcoin may even be cheaper than Ethereum while providing similar guarantees and security properties. While BVV posts data to Bitcoin it does not settle on Bitcoin or use BTC as its primary currency. Like other Rollups, BVV lives on an EVM compatible L1/L2 (currently on Sepolia) allowing it to settle ETH and use the EVM's expressive capabilities for settlement assurance.
Our project leverages existing work by the Optimism team in the form of Bedrock, which we forked and modified to use Bitcoin. In this process, we had to deeply familiarize ourselves with both Optimism's and Bitcoin's codebase. Beyond modifying Bedrock's Sequencer we also developed a simplified on-chain light client for Bitcoin that runs in the EVM. This would eventually allow for the settlement contract to validate and verify data posted to Bitcoin in the case of a dispute (fraud proof).