Random Linear Network Codes for Secrecy Over Wireless Broadcast Channels
The authors consider a set of n messages and a group of k clients. Each client is privileged for receiving an arbitrary subset of the messages over a broadcast erasure channel, which generalizes scenario of a previous work. They propose a method for secretly delivering each message to its privileged recipients in a way that each receiver can decode its own messages but not the others'. Their method is based on combining the messages using linear network coding and hiding the decoding coefficients from the unprivileged clients. They provide an information theoretic proof for the secrecy of the proposed method.