How to Prevent Frontrunning in DeFi
Christian Cachin
Tuesday, November 14, 2023
Talk at 4:00pm
Gates 104 & Zoom (https://stanford.zoom.us/j/92732897040?pwd=Q29JOFVFSy9kWXVDR3dIVWlGektFdz09)
Abstract:
Blockchain consensus protocols put miners and validators in charge of
ordering transactions into blocks. Validators control not only which
transactions appear in a block, but also the relative order of
transactions within. Such influence on the order constitutes a major
vulnerability for corresponding decentralized finance (DeFi) networks.
It allows, for example, that validators maximize their own profit at the
cost of innocent users, through so-called MEV attacks.
This presentation will dive into the front-running problem and explain
several defense methods that are currently being explored in theory and
practice:
1) Protecting the causal order among all transactions through
encryption, in the sense that transactions are encrypted by clients and
the validators agree on a sequence of encrypted transactions.
2) Receive-order fairness aims at ensuring that transactions that were
first received by "many" validators appear before transactions received
by "few". If the number of malicious validators is small, their power
to control the order and exploit frontrunning can be bounded.
3) Eliminating frontrunning through randomized ordering. This protocol
randomly permutes the transactions that appear in a block. The crux
lies in ensuring that the randomness used for the scrambling cannot be
biased by the malicious validator that creates the block.
This talk is based on joint work with Orestis Alpos, Ignacio Amores
Sesar, Jovana Micic, Nathalie Steinhauer, Michelle Yeo, and Luca
Zanolini.
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 during 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.