Fundamental Limits of Secure Device-to-Device Coded Caching

We consider a device-to-device coded caching system, where each user is guaranteed recover its requested file and is simultaneously prevented from recovering any file it did not request. We jointly optimize the cache placement and delivery policies such that a set of end users are able to satisfy their requests while preserving the confidentiality constraints. We develop an upper bound utilizing secret sharing schemes and one-time pad keying as well as a lower bound on the required transmission rate. Numerical results indicate that the gap between the bounds vanishes with increasing memory size.