General Purpose Atomic Crosschain Transactions

TL;DR

This paper introduces a protocol enabling atomic, cross-chain transactions across multiple Ethereum and potentially other blockchains, ensuring consistency and rollback capabilities for complex inter-chain operations.

Contribution

It presents a novel protocol for composable, atomic cross-chain transactions that operate without modifying existing blockchains and supports heterogeneous blockchain environments.

Findings

Analyzed Gas usage for different cross-chain scenarios

Evaluated finalised block periods in various transaction setups

Demonstrated safety and liveness properties of the protocol

Abstract

The General Purpose Atomic Crosschain Transaction protocol allows composable programming across multiple Ethereum blockchains. It allows for inter-contract and inter-blockchain function calls that are both synchronous and atomic: if one part fails, the whole call execution tree of function calls is rolled back. The protocol operates on existing Ethereum blockchains without modification. It works for both public permissioned and consortium blockchains. Additionally, the protocol is expected to work across heterogeneous blockchains other than Ethereum. This paper describes the protocol, analyses it in terms of Gas usage and Finalised Block Periods for three scenarios: reading a value from one blockchain to another, writing a value from one blockchain to another, and a trade finance system involving five contracts on five blockchains with a complex call execution tree, and provides an initial security analysis that shows that the protocol has Safety and Liveness properties.