BATTLE for Bitcoin: A DoS-Resilient Bridge Protocol for Bitcoin

BATTLE for Bitcoin introduces a new capital-efficient dispute resolution layer that brings optimistic bridging to Bitcoin, combining high decentralization with minimal capital requirements.

Current optimistic bridge designs rely on Turing-complete blockchains (like Ethereum) to manage dynamic dispute scheduling and resource protection. Bitcoin, however, poses a unique challenge: its UTXO-based, stateless scripting model limits dynamic logic and concurrency. This research shows how to overcome those constraints making efficient, trust-minimized bridges on Bitcoin possible.

At its core, BATTLE for Bitcoin adapts the BATTLE tournament protocol to Bitcoin through BitVM-style FLEX components and garbled circuits. Disputes are resolved in logarithmic rounds, with rewards recycled across rounds. This structure keeps the honest operator’s initial capital constant, even in the face of many challengers, a major step toward scalable, DoS-resistant bridges.

To handle concurrency and prevent overlapping assertions, the paper introduces the Tournament Chain (TC), a rate-limited mechanism that serializes tournament openings and prevents resource exhaustion.

The protocol’s design also incorporates on-demand Layer 1 security bonds, race-free early-refund mechanisms, and multi-party enablement chains, allowing both safety and liveness guarantees within Bitcoin’s native constraints.

BATTLE’s two-phase structure first eliminates conflicting assertions among bridge operators, then escalates challenges against the surviving claim using an economically sustainable tournament schedule. It achieves this while maintaining open participation: asserters provide liveness, while a large pool of watchtowers ensures safety by disputing invalid claims.

Ultimately, BATTLE demonstrates that large, permissionless committees -on the order of a thousand participants- can coordinate optimistic verification directly on Bitcoin without introducing new opcodes or external consensus. This positions BATTLE as a key building block for future Bitcoin rollups, sidechains, and interoperability protocols.

Dive deeper into the full research and technical design of BATTLE for Bitcoin 🔗here.