In this talk I will focus on sealed-bid auctions over the blockchain.The specific objectives are low interactivity between the parties to support broadcast via blocks on the blockchains and security against malicious adversaries with guaranteed output delivery. Hence, we dismiss powerful, yet highly-interactive MPC frameworks and propose a special-purpose protocol for secure computation of the kth-ranked integer, a basic building block for many types of auctions. Our protocol is practical, requiring only 3 rounds (blockchain blocks). Our implementation indicates that the main bottleneck, ZK proof computations, is small in practice: even for a large number of n = 200 parties and high-precision integers (l = 32), computation time of all proofs is less than a single Bitcoin block interval.

Bio: Florian Kerschbaum is an associate professor in the David R. Cheriton School of Computer Science at the University of Waterloo (since 2017) and Director of the Waterloo Cybersecurity and Privacy Institute (since 2018). Prior to this, he has worked as chief research expert at SAP in Karlsruhe (2005 – 2016) and as a software architect at Arxan Technologies in San Francisco (2002 – 2004). He holds a Ph.D. in computer science from the Karlsruhe Institute of Technology (2010) and a master's degree from Purdue University (2001). Florian is interested in data security and privacy in data management, machine learning, and blockchains. He extends real-world systems with cryptographic security mechanisms to achieve (some) provable security guarantees. His work has been applied to products for databases, supply chain management and RFID tracking.