# Atomic Cross-Chain Swaps

arXiv: https://arxiv.org/abs/1801.09515 · HTML: https://mlsanity.com/paper/1801.09515/

## Key facts

- Cited by 3 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 29 Jan 2018.

## Built on by (most cited first, 3 of 3)

- [Autonomous Agents on Blockchains: Standards, Execution Models, and Trust Boundaries](https://mlsanity.com/paper/2601.04583/) (2026)
- [Game of Trust: How Trustworthy Does Your Blockchain Think You Are?](https://mlsanity.com/paper/2505.14551/) (2025)
- [Fairly Compensated Distributed Information Retrieval and Augmentation for AI Agents](https://mlsanity.com/paper/2609.22601/) (2026)

## Abstract (arXiv)

An atomic cross-chain swap is a distributed coordination task where multiple parties exchange assets across multiple blockchains, for example, trading bitcoin for ether. An atomic swap protocol guarantees (1) if all parties conform to the protocol, then all swaps take place, (2) if some coalition deviates from the protocol, then no conforming party ends up worse off, and (3) no coalition has an incentive to deviate from the protocol. A cross-chain swap is modeled as a directed graph cal D, whose vertexes are parties and whose arcs are proposed asset transfers. For any pair (cal D,L), where cal D = (V,A) is a strongly-connected directed graph and L subset V a feedback vertex set for cal D, we give an atomic cross-chain swap protocol for cal D, using a form of hashed timelock contracts, where the vertexes in L generate the hashlocked secrets. We show that no such protocol is possible if cal D is not strongly connected, or if cal D is strongly connected but L is not a feedback vertex set. The protocol has time complexity O(diam(cal D)) and space complexity (bits stored on all blockchains) O(|A|2).