On Demand-Private Coded Caching With Multiple Demands

TL;DR

This paper introduces a new privacy-preserving coded caching scheme for multiple demands, transforming existing non-private schemes and establishing order-optimality within a factor of 6.

Contribution

It proposes a novel transformation-based scheme for private coded caching with multiple demands and derives a tight converse bound.

Findings

The scheme is order optimal within a factor of 6.

A new transformation from non-private to private caching schemes is developed.

The scheme applies to arbitrary numbers of files and users.

Abstract

We consider a coded caching problem with multiple demands under a privacy constraint. In this problem, a server with access to \(N\) files serves \(K\) users over a shared link, and each user requests \(L\) distinct files. The privacy constraint requires that each user obtain no information about the demands of the other users. We propose a new achievable scheme for arbitrary numbers of files and users. The scheme is obtained via a transformation from a non-private coded caching scheme under uncoded placement for \(N\) files and \(K \cdot \min\{N,KL\}\) users, where each user requests one file and the demands are restricted to a subset of all possible demands. We then derive a converse bound, and the proposed scheme is shown to be order optimal within a factor of 6 of this bound.