The Nuts and Bolts of Cross-Chain Communication
Duration: 00:52:05
Speaker: Mustafa Al-Bassam, Dominik Harz, Alexei Zamyatin
Type: Breakout
Expertise: intermediate
Event: Devcon
Date: Jul 2026
Throughout the past years, research into facilitating trustless cross-chain communication has resulted in the proposal of numerous concepts and mechanisms. However, to this date, the work is scattered across blog posts, scientific papers and code. The goal of this workshop is to provide an overview of the fundamentals of cross-chain communication, especially in cross-ledger exchanges and sharding. Our goal is that participants understand the differences between trusted/custodial and trustless/non-custodial approaches, and the challenges we face today.We split the workshop into 2 parts:Theory: Overview: motivation, challenges and different approaches and use cases. Focus on (i) cross-ledger exchanges (atomic swaps and cryptocurrency-backed assets), and (ii) sharding, (different proposals and how they handle cross-shard transfers). Two technical deep dives: chain relays and data availability / fraud proofsPractice: Interactive coding workshop: participants build their own Bitcoin chain relay. We provide Solidity code with missing code snippets and help participants find the correct solution. In the end, we present our example implementation and discuss the approaches found by workshop participants. People who do not wish to code or are unfamiliar with Solidity: interactive walk-though for the BTC Relay implementation + detailed discussion of possible attacks to foster adversarial thinking.
