Cache-aided combination networks with secrecy guarantees

In this paper, we study a cache-aided combination network, where a layer of relay nodes connects a server to a set of end users, under three different secrecy requirements. Both the relays and the end users are equipped with caches. First, we consider secure delivery where we require that an external entity must not gain any information about the database files by observing the transmitted signals over the network links. Second, we consider secure caching where we require that an end user must not be able to obtain any information about a file that he did not request. Last, we consider both of these requirements simultaneously. We jointly optimize the cache placement and delivery phases in order to minimize the delivery load over each of the two hops, and demonstrate the impact of the network topology on the system performance under these secrecy requirements.