Consensus in blockchains: Overview and recent results

Location: TU Wien, FAV Hörsaal 3 (Favoritenstr. 9-11)

Date & Time: 2023-06-21; 4pm

Abstract: Reaching consensus despite faulty or corrupted nodes is a central question in distributed computing; it has received renewed attention over the last years because of its importance for cryptocurrencies and blockchain networks. Modern consensus protocols in this space have relied on a number of different methods for the nodes to influence protocol decisions. Such assumptions include (1) traditional voting, where each node has one vote, (2) weighted voting, where voting power is proportional to stake in an underlying asset, and (3) proof-of-X, which demonstrates a cryptographically verifiable investment of a resource X, such as storage space, time waited, or computational work. This talk will give an overview of blockchain consensus methods and then highlight recent work on constructing new consensus protocols and analyzing existing ones.

Bio: Christian Cachin is a professor of computer science at the University of Bern, where he has been leading the Cryptology and Data Security Research Group since 2019. Prior to that he worked for IBM Research - Zurich for more than 20 years. He has held visiting positions at MIT and at EPFL and has taught at several universities during his career in industrial research. He graduated with a Ph.D. in Computer Science from ETH Zurich in 1997. He is an IACR Fellow, ACM Fellow, IEEE Fellow, recipient of multiple IBM Outstanding Technical Achievement Awards, and has also served as the President of the International Association for Cryptologic Research (IACR) from 2014-2019. With a background in cryptography, he is interested in all aspects of security in distributed systems and especially in cryptographic protocols, consistency, consensus, blockchains, and cloud-computing security. He is known for developing cryptographic protocols, particularly for achieving consensus and for executing distributed cryptographic operations over the Internet. In the area of cloud computing, he has contributed to standards in storage security and developed protocols for key management. He has co-authored a textbook on distributed computing titled Introduction to Reliable and Secure Distributed Programming. While at IBM Research he made essential contributions to the development of Hyperledger Fabric, a blockchain platform aimed at business use.