Cuttlefish: Expressive Fast Path Blockchains with FastUnlock

TL;DR

Cuttlefish introduces a novel blockchain protocol that reduces reliance on consensus for non-contentious transactions and employs a fast unlock mechanism to efficiently resolve contentions, expanding blockchain functionality.

Contribution

It presents a new approach using collective objects and multi-owner transactions, along with a fast unlock protocol, to enable consensus-less transactions and improve contention resolution.

Findings

Supports asset swaps and multi-signature transactions without full consensus

Reduces latency in unblocking contented objects significantly

Expands the range of transactions possible without consensus

Abstract

Cuttlefish addresses several limitations of existing consensus-less and consensus-minimized decentralized ledgers, including restricted programmability and the risk of deadlocked assets. The key insight of Cuttlefish is that consensus in blockchains is necessary due to contention, rather than multiple owners of an asset as suggested by prior work. Previous proposals proactively use consensus to prevent contention from blocking assets, taking a pessimistic approach. In contrast, Cuttlefish introduces collective objects and multi-owner transactions that can offer most of the functionality of classic blockchains when objects transacted on are not under contention. Additionally, in case of contention, Cuttlefish proposes a novel `Unlock' protocol that significantly reduces the latency of unblocking contented objects. By leveraging these features, Cuttlefish implements consensus-less protocols for a broader range of transactions, including asset swaps and multi-signature transactions, which were previously believed to require consensus.