Snowman is the consensus protocol run by blockchains on Avalanche. Recent work of ours established a rigorous proof of probabilistic consistency for Snowman in the synchronous setting, under the simplifying assumption that correct processes execute sampling rounds in `lockstep’. In this paper, we describe a modification of the protocol that ensures consistency in the partially synchronous setting, and when correct processes carry out successive sampling rounds at their own speed, with the time between sampling rounds determined by local message delays.

Joint work with Aaron Buchwald, Stephen Buttolph, and Kevin Sekniqi.

Snowman for partial synchrony, pdf.