Multiple Access Covert Channels

Abstract : In this paper we consider the situation of multiple malicious transmitters attempting to covertly communicate with a single receiver, We show how the situation of non-collaborating transmitters can be modeled by multiple access channels. The simpler situation of collaborating transmitters is used as a bounding result. We also discuss the surprising results of Gaarder and Wolf that feedback can increase capacity unlike the situation for standard covert channel analysis. This is of importance when dealing with the network scenario.