Efficient Cross-Blockchain Token Transfers with Rollback Support

Abstract

Blockchain interoperability still poses a significant challenge to the practical applicability of Distributed Ledger Technologies (DLTs). However, several cross-blockchain protocols already exist, allowing, e.g., the transfer of tokens between heterogenous blockchains. Unfortunately, executing these protocols is expensive and often does not consider eventual inconsistencies, which can occur if the involved blockchains fork.Therefore, we propose a cross-blockchain token transfer protocol operating on Layer 2 to decrease transaction costs and enable the ability to revert transactions. The protocol uses the approach of zk rollups to move storage and computation off-chain and only stores state commitments on Layer 1. Hence, the states of the involved token contracts can quickly revert to an older state root to account for possible forks of the involved blockchains and ensure consistency.