Avihu Levy | Bitcoin Horizons: from OP_CAT to Covenants | Hong Kong

Presenting ColliderVM, a protocol for enabling stateful computation on Bitcoin that persists across multiple transactions and user interactions. Designed by StarkWare researchers Victor I. Kolobov, Avihu M. Levy, and the Weizmann Institute of Science Professor Moni Naor. The protocol is designed to facilitate trust-minimized bridging between Bitcoin and Layer 2 networks such as Starknet, using a validity-based computation model (ZK proof) rather than fraud proofs. Unlike prior constructions such as BitVM2, ColliderVM eliminates the need for on-chain watchers and dispute periods, thereby improving capital efficiency for bridge operators and reducing operational complexity. Additionally, ColliderVM supports both SNARK and STARK based proof systems, expanding flexibility for scaling solutions.

ColliderVM leverages hash collision-based puzzles to pass data across Bitcoin transactions, replacing signature-based methods used in prior designs. This approach yields significant improvements in efficiency, both in terms of transaction size and computational requirements. The security model assumes a minimal threshold of honest participants among signers and bridge operators to guarantee both safety and liveness. While the protocol introduces some costs in terms of on-chain data and signature management, we believe it represents a meaningful step toward scalable, minimally trusted Bitcoin interoperability.

Full details are available in the accompanying paper: ColliderVM: Stateful Computation on Bitcoin.