Multiple Trojan horse systems and covert channel analysis

The multiple Trojan horse system is a finite-state deterministic model with a high-level transmitter Trojan horse process, a low-level receiver Trojan horse process, and m conspiring Trojan horse processes. The conspiring processes attempt to aid the downgrading of data from the transmitter to the receiver. The capacity of a multiple Trojan horse system is a measure of the amount of information the high-level process can disclose to the low-level process. Any controlled signalling system can be viewed as a multiple Trojan horse system. The author gives an optimality equation which gives a way to recursively construct optimal strategies for both the receiver and conspiring processes. Computer algorithms can be constructed to iteratively compute the capacity and optimal strategies