Efficient Private Techniques for Verifying Social Proximity

A variety of peer-to-peer systems use social networks to establish trust between participants. Yet the sharing of social information introduces privacy concerns. This paper proposes new privacy-preserving cryptographic protocols that enable participants to verify social proximity while exposing minimal information about the parties’ social contacts. Compared to previous results, our protocols are either significantly more efficient (orders of magnitude faster than PM [3]) or achieve stronger security properties at