Abstract

The problem of secure friend discovery on a so-cial network has long been proposed and stud-ied. The requirement is that a pair of nodes can make befriending decisions with minimum infor-mation exposed to the other party. In this paper, we propose to use community detection to tackle the problem of secure friend discovery. We for-mulate the first privacy-preserving and decentral-ized community detection problem as a multi-objective optimization. We design the first proto-col to solve this problem, which transforms com-munity detection to a series of Private Set In-tersection (PSI) instances using Truncated Ran-dom Walk (TRW). Preliminary theoretical results show that our protocol can uncover communities with overwhelming probability and preserve pri-vacy. We also discuss future works, potential ex-tensions and variations. 1