Variable noise effects upon a simple timing channel

Abstract

Investigates the effects of noise upon a simple timing channel. Shannon's information theory (C. Shannon et al., 1949) is used to quantify the resulting information flow across the channel. In particular the author studies how a probabilistic response time to a query by a low user affects the mutual information and channel capacity. He claims that we will never eliminate all covert channels in a multi-user computer system without serious degradation of performance. Therefore, it is important to know how 'bad' the covert channels are. One way to do this is through an information theoretic capacity analysis.<>