A content-delivery protocol, exploiting the privacy benefits of coded caching

Abstract

Coded caching is a communications technique that has elevated the preemptive use of memory (caching) into a powerful ingredient in general communications networks, promising to change the way networking and PHY-based communications are conducted. At the same time though — because this approach is heavily dependent on cooperation between the content provider (CP), and a centralized powerful transmitter of information (ISP), and because it is heavily dependent on users caching a variety of content that is not their own — raises privacy concerns which have the potential to compromise the applicability of coded caching. What we are showing in this early work here, is that in fact coded caching carries a distinct set of salient features that in fact boost privacy. We present a step-by-step privacy-aware content-delivery protocol that utilizes caching and which — at a small cost in performance — can safeguard against unauthorized matching of users to their requests, as well as against unauthorized knowledge of the popularity statistics of files; both crucial privacy issues in different scenarios such as video on demand. These properties include multicasting-only transmissions for continuous obfuscation of the true destination of content, an almost seamless addition of phantom users that can skew the true popularity distribution, popularity-agnostic caches, cache-agnostic ISP, and an overall minimization of data traffic between CP and ISP, and between ISP and users.