The influence of delay upon an idealized channel's bandwidth
Ira S. Moskowitz, Allen R. Miller · 2003
An optimization problem in calculating the bandwidth of a covert timing channel is discussed. In particular, the question of how dependent the bandwidth is on the magnitude of the modulation is addressed. A generalization of that covert channel is presented and its bandwidth (capacity) is studied. Attention is given to how the delay that HIGH uses to signal LOW affects the bandwidth. Increasing the delay lessens the noise but increases the time required to pass a symbol along the channel. What the optimal delay should be and how it influences the security of the system was studied. Because of the complicated nature of the formulas involved, closed-form solutions for some of the terms of interest cannot be given. Instead, numerical techniques and plotted results are used.>