Extended Combinatorial Constructions for Peer-to-Peer User-Private Information Retrieval
The authors consider User-Private Information Retrieval (UPIR), an interesting alternative to Private Information Retrieval (PIR) introduced by Domingo-Ferrer et al.. In UPIR, the database knows which records have been retrieved, but does not know the identity of the person making the query. The goal of UPIR, then, is to disguise user profiles from the point of view of the database. Domingo-Ferrer et al., focus on using a peer-to-peer community to construct a UPIR scheme, which they term P2P UPIR. In this paper, they establish a strengthened model for P2P UPIR and clarify the privacy goals of such schemes using standard terminology from the field of privacy research.