FastPay allows a set of distributed validators, some of which are Byzantine, to maintain a high-integrity and availability settlement system for pre-funded payments. This is not the protocol Sui uses, yet it proposes the basic safety mechanism that Sui extends.

Narwhal is a mempool protocol specializing in high-throughput reliable dissemination and storage of causal histories of transactions. Tusk is a zero-message overhead asynchronous consensus protocol that works with Narwhal.

Bullshark is the consensus engine that agrees on the specific order of data. Sui uses the partially synchronous version described in this paper.