Afgjort: A Partially Synchronous Finality Layer for Blockchains
Thomas Dinsdale-Young, Bernardo Magri, Christian Matt, Jesper Buus Nielsen, Daniel Tschudi · IACR Cryptology ePrint Archive · 2019
Most existing blockchains either rely on a Nakamoto-style of consensus, where the chain can fork and produce rollbacks, or on a committee-based Byzantine fault tolerant (CBFT) consensus, where no rollbacks are possible. While the latter ones offer better consistency, the former tolerate more corruptions. To achieve the best of both worlds, we initiate the formal study of finality layers. Such a finality layer can be combined with a Nakamoto-style blockchain (NSB) and periodically declare blocks as final, preventing rollbacks beyond final blocks.