Fundamental limits of caching with secure delivery

Caching is a procedure which allows popular files to be pre-fetched and stored partly in end users' memory. In modern wireless networks, caching is emerging to play a vital role in reducing peak data rates by storing popular content. In this paper, the concept of information theoretic security for caching is introduced. A novel caching scheme is proposed which leverages both the local and global caching gains to reduce peak rate while securely delivering requested content to the users. The analysis of the secure caching problem is presented which shows that the proposed scheme introduces security at negligible cost compared to insecure caching schemes, particularly for large number of files and users. It is also shown that the rate of the proposed scheme is within a constant multiplicative factor from the information-theoretic optimal rate for all feasible values of problem parameters.