Atomicity and Abstraction for Cross-Blockchain Interactions

TL;DR

This paper introduces a high-level abstraction and a protocol for atomic, secure cross-chain transactions, simplifying multi-blockchain application development and ensuring correctness and security.

Contribution

It defines a uniform interface and a protocol for atomic cross-chain transactions, extending beyond cryptocurrency swaps to general multi-chain operations.

Findings

The protocol guarantees atomicity and security for cross-chain transactions.

Implementation with LayerZero shows simplified development and comparable performance.

The approach generalizes multi-chain transaction handling beyond existing limited methods.

Abstract

A blockchain facilitates secure and atomic transactions between mutually untrusting parties on that chain. Today, there are multiple blockchains with differing interfaces and security properties. Programming in this multi-blockchain world is hindered by the lack of general and convenient abstractions for cross-chain communication and computation. Current cross-chain communication bridges have varied and low-level interfaces, making it difficult to develop portable applications. Current methods for multi-chain atomic transactions are limited in scope to cryptocurrency swaps. This work addresses these issues. We first define a uniform, high-level interface for communication between chains. Building on this interface, we formulate a protocol that guarantees atomicity for general transactions whose operations may span several chains. We formulate and prove the desired correctness and security properties of these protocols. Our prototype implementation is built using the LayerZero cross-chain bridge. Experience with this implementation shows that the new abstractions considerably simplify the design and implementation of multi-chain transactions. Experimental evaluation with multi-chain swap transactions demonstrates performance comparable to that of custom-built implementations.