Date(s) - 02/05/2019
6:00 pm - 8:00 pm
Fields Institute, Room 230
About the Series
Blockchain technology is starting to emerge as a genuine disruptive force in finance, business and many other areas. Applications have grown beyond cryptocurrencies to smart-contracts, distributed ledgers, online voting, insurance, and the healthcare supply chain to name a few. Some believe that there is tremendous potential for blockchain technologies to usher in an era of unprecedented trust and transparency, but there still exist fundamental questions that need to be answered.
This seminar series seeks to assemble mathematicians, statistician, computer scientists, and other research scientists as well as industry experts to discuss the current breakthroughs and research challenges in areas that underpin blockchain technology.
Elias Koutsoupias, University of Oxford
Incentive vulnerabilities of proof-of-work blockchains
Blockchain protocols based on proof-of-work induce miners, through monetary rewards, to expend energy in order to add blocks to the chain. I will discuss some vulnerabilities that arise from incentives in this framework and some potential remedies. The best-known vulnerability comes from mining games, a type of stochastic games. Miners are expected to build a chain of blocks by adding new blocks to the end of it, however if they have sufficient computational power they are better off deviating from the expected behaviour. I will discuss a few possible deviations: extending the chain from a past block, hiding newly minted blocks, and varying the energy expended from epoch to epoch. Mining games can be partially alleviated when weak miners expand their strategies to pay other miners, and energy strategic deviations can be prevented by changing the mechanism for deciding the difficulty of producing a block.
Elias Koutsoupias is a professor of computer science at the University of Oxford, UK. He previously held faculty positions at the University of California, Los Angeles (UCLA) and the University of Athens. His research interests include algorithmic aspects of game theory, economics and networks, online algorithms, decision-making under uncertainty, design and analysis of algorithms, and computational complexity. He received the Godel Prize of theoretical computer science for his work on the Price of Anarchy, in reference to laying the foundations of algorithmic game theory. He is also the recipient of an ERC Advanced Grant.