The Distinguished Lecture Series of the Department of Computer Science at the University of Innsbruck seeks to bring new perspectives and ideas to our researchers, students, alumni and friends.


It is our great pleasure to announce the next distinguished computer science lecture by Ittay Eyal, Research Associate at Cornell University and Associate Director IC3:

Removing the Limits of Blockchain Protocols

Date: Tuesday, 4th of April 2017, 6 pm
Location: SR2, ICT Technologiepark, Campus Technik

Please register here!


The study of security in decentralized large-scale distributed systems has made a large leap forward when Satoshi Nakamoto presented Bitcoin and Blockchain-based cryptocurrencies in general. Nakamoto’s blockchain achieves a secure and resilient variant of consensus in a permissionless model using proof-of-work: participants solve computationally-difficult puzzles, send a proof, and are compensated for their efforts.

But Nakamoto’s blockchain has limitations that are both challenging from a theoretical perspective and are deterring blockchain adoption by practitioners in the FinTech industry. This talk will focus on overcoming two of these challenges.

1. In Nakamoto’s blockchain, increasing throughput or reducing latency results in a deterioration of the probabilistic security guarantees offered by the system. Our blockchain protocol, Bitcoin-NG (Next Generation), demonstrates that security does not inherently stand at odds with performance at the adversarial environments where blockchain algorithms live. We demonstrate NG’s performance in a 1000-node blockchain lab-experiment.

2. Proof-of-work protocols are generally wasteful, as the work done is useless beyond its contribution to blockchain security. We propose to use instead Proof of Useful Work (PoUW) — an alternative that employs useful work for blockchain security. We use Trusted Execution Environments, Intel’s SGX technology in particular, to securely implement this mechanism. We analyze the waste reduction with game-theoretic tools and use statistical techniques to overcome the compromise of individual SGX units.

The talk is self-contained and does not assume previous knowledge of Blockchain protocols.

More about Ittay Eyal on his website!

This talk is organized together with the Austrian-Israel Academic Network Innsbruck.

AIANI Logo englisch 2016

Universität Innsbruck