Some results on query processes and reconstruction functions for unconditionally secure 2-server 1-round binary private information retrieval protocols

Abstract

In this paper, we investigate query processes and reconstruction functions for unconditionally secure 2-server 1-round binary private information retrieval (PIR) schemes. We begin by formulating a simplified model for PIR schemes which is equivalent to the usual model. We show that a query is equivalent to a boolean function of two variables, and we give a precise characterization of the boolean functions that can be used as "query pairs" to the two servers. We also consider several notions of "privacy" and we make a few remarks about the communication complexity of PIR schemes.

Keywords

• private information retrieval,
• boolean functions