Speaker: Sanaz Taheri-Boshrooyeh, Koç University

Title: A Framework of Privacy-Preserving Services for Distributed Online Social Networks

Date/Time: October 16, 2019  /  13.40-14.30

Place: FENS G032

Abstract: Online Social Network (OSN) providers like Facebook, Twitter and Google+ supply storage and computational resources for the users and enable them to share personal information and establish friendships. The collection of users data at a central OSN provider causes security issues due to which the distributed OSNs with federated server architecture is proposed. The central provider is replaced by multiple servers (running by distinct providers) which run OSN services collaboratively while no server is fully trusted. We utilize the federated server architecture and the trust distribution among the servers to propose a framework of efficient and privacy-preserving services for OSNs that would be otherwise impossible in the centralized versions.

The first module of the framework, Privado, is a privacy-preserving group-based advertising method through which OSN servers can find the advertiser's target customers using users' encrypted profiles. The second module of the framework, Anonyma, copes with the inference attack in the invitation-only nature of OSNs' group formation. Anonyma is an invitation-based system where users prove to the administrator that they are invited by a certain number of group members without revealing their inviters. The third module of the framework, Integrita, is a  collaborative data-sharing platform (e.g., Facebook groups) that preserves view consistency against corrupted servers i.e., servers cannot show divergence view of the shared data (e.g., posts of the group page) to the users (e.g.,  group members) without being detected. Every user, without relying on the presence of other users, can verify any server-side equivocation regarding her performed operation.

BIO: Sanaz Taheri-Boshrooyeh received B.S. degree in computer engineering (software) from Shiraz University, Iran in 2013, and Ph.D. degree in computer science and engineering from Koç University, Istanbul, Turkey, in 2019. Her research interests are cryptography, data privacy, secure multi-party computations, and distributed systems and applications.

Contact: Öznur Taştan