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 major 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 that better incentivizes honest behavior. Hybrid Consensus offers efficiency bootstrapping 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.
Elaine Shi is an Associate Professor of Computer Science at Cornell University, and co-director of the Initiative for Cryptocurrency and Contracts (IC3, www.initc3.org). Her research focuses on security, cryptography, and programming languages. Elaine obtained her Ph.D. from Carnegie Mellon University in 2008, and B.E. from Tsinghua University in 2003. She is the recipient of a Packard Fellowship, a Sloan Fellowship, a VMWare Research award, an NSA Best Scientific Cybersecurity Paper Award, an ONR YIP award, and various other research awards and best paper awards.