Atomic Crosschain Transactions for Ethereum Private Sidechains
This addresses the need for private and secure cross-blockchain communication for enterprises using private sidechains, though it is incremental as it builds on existing blockchain technologies.
The paper tackles the problem of enabling atomic transactions across multiple private Ethereum sidechains, proposing a crosschain technique with a new proof mechanism, transaction locking, and global time-out to allow functions in one sidechain to securely interact with another, exemplified by an atomic swap contract for value exchange.
Public blockchains such as Ethereum and Bitcoin do not give enterprises the privacy they need for many of their business processes. Consequently consortiums are exploring private blockchains to keep their membership and transactions private. Ethereum Private Sidechains is a private blockchain technology which allows many blockchains to be operated in parallel. Communication is needed between Ethereum Private Sidechains to allow a function in a contract on one sidechain to execute function calls which return values from, or update the state of, another sidechain. We propose a crosschain technique which allows transactions to be executed atomically across sidechains, introduce a new mechanism for proving values across sidechains, describe a transaction locking mechanism which works in the context of blockchain to enable atomic transactions, and a methodology for providing a global time-out across sidechains. We outline the programming model to be used with this technology and provide as an example, a variable amount atomic swap contract for exchanging value between sidechains. Although this paper presents Atomic Crosschain Transaction technology in the context of Ethereum Private Sidechains, we discuss how this technology can be readily applied to many blockchain systems to provide cross-blockchain transactions.