Atomic Transfer Graphs: Secure-by-design Protocols for Heterogeneous Blockchain Ecosystems

TL;DR

This paper introduces a framework for designing secure blockchain protocols using atomic transfer graphs (ATGs), enabling secure cross-chain transfers and applications with provable security and improved performance.

Contribution

The paper presents a novel framework utilizing atomic transfer graphs and Conditional Timelock Contracts to generate secure, versatile protocols for heterogeneous blockchain ecosystems.

Findings

Framework supports secure cross-chain transfers.

Protocols match or outperform existing solutions.

Applicable to various cryptocurrencies and applications.

Abstract

The heterogeneity of the blockchain landscape has motivated the design of blockchain protocols tailored to specific blockchains and applications that, hence, require custom security proofs. We observe that many blockchain protocols share common security and functionality goals, which can be captured by an atomic transfer graph (ATG) describing the structure of desired transfers. Based on this observation, we contribute a framework for generating secure-by-design protocols that realize these goals. The resulting protocols build upon Conditional Timelock Contracts (CTLCs), a novel minimal smart contract functionality that can be implemented in a large variety of cryptocurrencies with a restricted scripting language (e.g., Bitcoin), and payment channels. We show how ATGs, in addition to enabling novel applications, capture the security and functionality goals of existing applications, including many examples from payment channel networks and complex multi-party cross-currency swaps among Ethereum-style cryptocurrencies. Our framework is the first to provide generic and provably secure protocols for all these use cases while matching or improving the performance of existing use-case-specific protocols.