Scalable and Incentive-Compatible Blockchain Design

Elaine Shi


The distributed systems and cryptography literature has traditionally focused on the "permissioned" model where protocol participants are known a priori. Bitcoin's rapid rise to fame represents an exciting breakthrough: it popularized a "permissionless" model where anyone can join and leave dynamically, and there is no prior knowledge of other participants.

Bitcoin's core protocol is commonly referred to as a "blockchain", which, roughly speaking, realizes a consensus abstraction ensuring consistency and liveness. Today's blockchain protocols, however, suffer from two main drawbacks that have given rise to vigorous debates in the community: 1) existing protocols have terrible performance; 2) existing protocols are not incentive compatible and selfish mining attacks are well-known.

In this talk, we present two latest results that address these painpoints, Fruitchain and Hybrid Consensus. Fruitchain is a new, game theoretically secure blockchain design that incentivizes honest behavior. Hybrid Consensus offers an efficiency bootstrapping theorem for permissionless consensus: we show how to leverage a slow blockchain protocol to bootstrap classical Byzantine Fault Tolerance protocols, such that we can achieve consensus in the permissionless setting while attaining the performance of their permissioned counterparts.

Joint work with Rafael Pass.

Time and Place

Friday, May 13, 4:15pm
Gates 463