Game Theoretical Analysis of Atomic Cross-Chain Swaps

Marianna Belotti (1, 2) , Stefano Moretti (3) , Maria Potop-Butucaru (4, 5) , Stefano Secci (1)

1 CEDRIC - ROC - CEDRIC. Réseaux et Objets Connectés
2 CDC - Caisse des dépôts et consignations (France)
3 LAMSADE - Laboratoire d'analyse et modélisation de systèmes pour l'aide à la décision
4 NPA - Networks and Performance Analysis
5 LINCS - Laboratory of Information, Network and Communication Sciences

In this paper we address the distributed cross-chain swap problem in the blockchain context where multiple agents exchange assets across multiple blockchain systems (e.g. trading Bitcoins for Litecoins or Ethers). We present a mathematical framework allowing to characterize blockchain swap protocols as the combination of a publishing and a commitment phase, where contracts are respectively published and then committed. We characterize the equilibria of existing cross-chain swap protocols (i.e., blockchain swap protocols exchanging assets among different blockchains). More precisely, we prove that following a swap protocol characterized by concurrent publishing of exchange contracts and snap (immediate) assets transfers is a Nash equilibrium. Furthermore, we prove that for protocols with a sequential publishing and commitment of the assets transfers, following the prescribed protocol is a sub-game perfect equilibrium.

Mots clés: Escrow; Interoperability; Atomic swap; Blockchain technology

Domaines: Informatique et théorie des jeux [cs.GT]

Marianna Belotti, Stefano Moretti, Maria Potop-Butucaru, Stefano Secci. Game Theoretical Analysis of Atomic Cross-Chain Swaps. 40th IEEE International Conference on Distributed Computing Systems (ICDCS), Nov 2020, Singapore, Singapore. ⟨10.1109/ICDCS47774.2020.00060⟩. ⟨hal-02414356⟩