Pike: Two-Phase BFT with Linearity and Flexible View Change

As the first Byzantine fault-tolerant (BFT) protocol with linear communication complexity, HotStuff (PODC 2019) has received significant attention. HotStuff has three round-trips for both normal case operations and view change protocols. Follow-up studies attempt to reduce the number of phases for HotStuff. However, most studies give up on one thing in return for another. This paper extends our previous work Marlin (DSN 2022) to Pike, another BFT protocol with two phases and linear communication complexity. Both Pike and Marlin use the same cryptographic tools as in HotStuff and introduce no additional assumptions. Marlin has a more efficient view change (i.e., leader election) protocol but a more complicated data structure. Pike further simplifies the data structure at the cost of longer view changes in extreme cases. We implement the Pike, Marlin, HotStuff, and HotStuff-2, showing that both Pike and Marlin outperform HotStuff in normal case operations.