UK-SPS Seminar 20th October 2021 - Title: Polynomial Representation Is Tricky

Title: Polynomial Representation Is Tricky: Maliciously Secure Private Set Intersection Revisited 

Speaker: Aydin Abadi (UCL)

Abstract: Private Set Intersection protocols (PSIs) allow parties to compute the intersection of their private sets, such that nothing about the sets’ elements beyond the intersection is revealed. PSIs have a variety of applications, primarily in efficiently supporting data sharing in a privacy-preserving manner. At Eurocrypt 2019, Ghosh and Nilges proposed three efficient PSIs based on the polynomial representation of sets and proved their security against active adversaries. In this talk, I will discuss that these three PSIs are susceptible to several serious attacks. The attacks let an adversary (1) learn the correct intersection while making its victim believe that the intersection is empty, (2) learn a certain element of its victim’s set beyond the intersection, and (3) delete multiple elements of its victim’s input set. I will explain why the proofs did not identify these attacks and discuss how the issues can be rectified.

This is a joint work with Steven Murdoch (UCL) and Thomas Zacharias (University of Edinburgh). 

Bio: Aydin Abadi is a research fellow at UCL. His research interests include information security, privacy, cryptography, and blockchain technology. Prior to holding this position, he held lectureship and research associate positions at the University of Gloucestershire and Edinburgh respectively. He completed his PhD at the University of Strathclyde under the supervision of Dr Changyu Dong.

Please feel free to forward to others who might be interested. 

UK-SPS is an inter-university seminar series on cyber security and privacy. Seminar details are also advertised on our website, calendar and Twitter, and recordings will be available on our YouTube channel afterwards. 

Last modified: Mon, 25 Oct 2021 10:29:59 BST