DRA

L2L Spaces w/ Paul Sztorc, Super Testnet, and Orkun

February 9, 2024Original source

On February 9, 2024, LayerTwo Labs hosted Paul, Super Testnet, and Orkun for a discussion covering Chainway’s BitVM-based ZK rollup work, Bitcoin data availability, sidechain architecture, and the distinct scaling and incentive design of Drivechain and BIP300/301.

Highlights

Key Takeaways

Chainway’s BitVM evolution

Orkun traced Chainway Labs’ path from a client-side-validated sovereign rollup toward a BitVM-based ZK rollup. The team had already inscribed transaction data and proofs on Bitcoin, then demonstrated Groth16 proof verification in BitVM while reducing the computation from roughly 20 billion to 4 billion cycles through new shift instructions. The discussion clarified that its execution layer offloads computation while Bitcoin retains the data needed to reconstruct state. Chainway planned to open-source the code and move into public testing, with remaining engineering centered on a complete peg and production-ready withdrawal flow.

Defining Bitcoin rollups

The speakers separated several concepts that are often grouped under the rollup label. A conventional rollup places the inputs required to reconstruct its global state on the base chain while external software performs execution; a sovereign rollup can add that interpretation without automatically providing a Bitcoin two-way peg. BitVM can then supply an optimistically verified bridge with bounded dispute participants. This framing distinguished rollups from Lightning’s channel-local state and from Drivechain, where the sidechain maintains its own full history while BIP300 anchors deposits and withdrawals to Bitcoin.

Drivechain’s validation model

Paul presented Drivechain as a deliberate division of validation work: sidechain users follow the sidechain’s full state, while Bitcoin validates the peg’s deposits and withdrawals through BIP300. Withdrawal proposals remain visible over a roughly three-month voting period, giving merge miners a sustained, auditable process for authorizing movement back to Bitcoin. BIP300/301 aligns miners with sidechain transaction fees through Blind Merged Mining, keeping economic value connected to Bitcoin’s security ecosystem. The design also lets multiple sidechains pursue different rules and applications without requiring every Bitcoin node to execute every sidechain transaction.