Frosty: Bringing strong liveness guarantees to the Snow family of consensus protocols

Snowman is the consensus protocol implemented by the Avalanche blockchain and is part of the Snow family of protocols, first introduced through the original Avalanche leaderless consensus protocol. A major advantage of Snowman is that each consensus decision only requires an expected constant communication overhead per processor in the common case that the protocol is not under substantial Byzantine attack — it provides a solution to the scalability problem which ensures that the expected communication overhead per processor is independent of the total number of processors during normal operation.

Andrew Lewis-Pye (LSE) discusses recent work with Ava Labs that addresses two issues with the Snowman consensus protocol. He considers a Byzantine adversary that controls substantial processors. First, he provides a simple proof of consistency for Snowman. Then he supplements Snowman with a liveness module that can be triggered in the case that a substantial adversary launches a liveness attack, and which guarantees liveness in this event by temporarily forgoing the communication complexity advantages of Snowman, but without sacrificing these low communication complexity advantages during normal operation.

About the presenter

Andrew is a mathematician and computer scientist and is a professor at the London School of Economics. About a16z crypto research a16z crypto research is a multidisciplinary lab that works closely with our portfolio companies and others toward solving the important problems in the space, and toward advancing the science and technology of the next generation of the internet.

More about us:

a16z.com/2022/04/21/announcing-a16z-crypto-research