Speaker/Bio
Sarah Scheffler is a 3rd-year PhD student studying with Prof. Mayank Varia. Her research interests include multi-party computation, secure messaging, and other applied cryptography. She also dabbles in solving problems in the intersection of law and computer science.
Abstract
When a user installs a private chat system like Signal, the system first determine which of the user's contacts also use the system. In keeping with the spirit and purpose of end-to-end encryption, this should be determined in a way that preserves the privacy of the user's contact list. The resulting problem, Private Contact Discovery, can be solved using Private Set Intersection (PSI). PSI has been around for 15 years, but several recent improvements in the underlying protocols and new algorithms have brought renewed interest to PSI for private contact discovery. This talk will describe the general PSI problem for private contact discovery, and will summarize several recent improvements, by Kales et al. (to be presented at Usenix Security 2019), Ion et al. (from Google), and Pinkas et al. (presented at Eurocrypt 2019).