05-28, 10:00–10:25 (CET), Seed
What if we could create a single L2 with native bridges to Ethereum and Bitcoin? We present Hybrid L2s: An L2 combining Bitcoin and Ethereum, extending the OP stack with BitVM (fraud proofs on Bitcoin), validity proofs, Bitcoin-staking with extractable one-time signature schemes, and hybrid DA with blobs and Bitcoin.
In this talk, we explore new technologies enabling native Bitcoin bridges (BitVM), settlement on multiple L1s with BTC-staking finality and validity proofs, trade-offs in DA, and opportunities for Ethereum with Hybrid L2s.
With the emergence of BitVM, we can build drastically better BTC bridges that reduce trust from a (super)-majority quorum to a 1-of-N assumption. However, BitVM relies on stateless light clients that are hard to build for Ethereum. Hence, we apply a trick for constructing the Hybrid L2: The L2 bridge finality on Bitcoin and Ethereum is a fusion of validity proofs of the L2 and BTC-staking with extractable one-time signatures (OTS). Validity proofs prevent malicious parties from committing safety violations. OTS introduces slashing of equivocation directly on Bitcoin. With BitVM, validity proofs, and BTC-staking, we can support native bridges to Bitcoin and Ethereum on a single L2.
Dominik Harz co-founded BOB, a first-of-its-kind hybrid Layer-2 powered by Bitcoin and Ethereum. Dominik is the CTO of Distributed Crafts, the organization behind the creation of BOB. He has been a contributor to DeFi and smart contracts R&D since 2016 and is most known for his work on DeFi security, stablecoins, and smart contracts. Dominik holds a PhD in computer science from Imperial College London.