BitVMX FORCE at Bitcoin++ Berlin: Lightning the Path Forward in Bitcoin Infrastructure
Building Secure and Watchtower-Efficient Payment Channels with BitVMX
On Day 1, Sergio Lerner took the main stage to present “Building Secure and Watchtower-Efficient Bitcoin Payment Channels with BitVMX.” The talk introduced two novel payment channel constructions: one using one-time signatures (OTS), and another more flexible design powered by BitVMX. Both designs enable efficient state revocation, allowing for lightweight watchtower infrastructure while preserving payment route privacy to prevent information leakage.
Both channels are compatible with HTLCs, making them integrable into the Lightning Network. The OTS-based channel uses one-time signatures for sequence number commitment, while the BitVMX-based version builds upon it by incorporating Schnorr-signed revocation messages.
Unlike traditional Lightning Network watchtowers—which must store data for every state update—the new channels require only O(1) storage per channel by tracking just the most recent revocation message. BitVMX channels also support path unlikability, using elliptic curve points as hashes and discrete logarithms as preimages, similar to PTLCs (Point Time-Locked Contracts).
Sergio's presentation highlighted how BitVMX extends Bitcoin’s capabilities to support secure, efficient, and flexible off-chain protocols—with minimal on-chain footprint.
Building Secure and Watchtower-efficient Bitcoin Payment Channels with BitVMX
A sample payment channel that uses BitVMX to support efficient revocations. It can be easily extended to function as a state channel and support Hash-Time Locked Contracts (HTLCs) for lightning-like routing.
Hackathon: BitVMX Workshop and Protocols in Action
BitVMX FORCE kicked off BTC++ Berlin with a workshop introducing developers to the architecture and design space of BitVMX. The session covered the foundational elements of the platform—from its RISC‑V virtual CPU to the constraint systems and verification strategies that enable expressive, trust-minimized computation over Bitcoin. Builders explored new ideas around interactive proofs, off-chain execution, and modular protocol composition.
Throughout the three-day Lightning++ hackathon, participants experimented with a range of ideas to scale Bitcoin using Layer 2 infrastructure. The BitVMX platform sparked interest and discussion among attendees, particularly in the wake of the workshop. To continue supporting developers who want to explore BitVMX further, the incentive reward sponsored by BitVMX FORCE—2 million satoshis—remains open. The hackathon window for BitVMX-based submissions has been extended by one month, with a new Devpost deadline to be announced shortly. We’ll also be providing all the necessary documentation and technical resources to help teams get started. We’re excited to see what emerges when teams have more time to build and experiment.
