Private Coded Caching

Recent work by Maddah-Ali and Niesen (2014) introduced coded caching which demonstrated the benefits of joint design of storage and transmission policies in content delivery networks. They studied a setup where a server communicates with a set of users, each equipped with a local cache, over a shared error-free link and proposed an order-optimal caching and delivery scheme. In this paper, we introduce the problem of private coded caching where we impose the additional constraint that no user learns any information about the contents of the files it did not request from what is stored in its cache and the server transmissions. We propose a feasible scheme for this setting and demonstrate its order-optimality by deriving information-theoretic lower bounds