Covert Channels for Collusion in Online Computer Games

Collusion between partners in Contract Bridge is an oft-used example in cryptography papers and an interesting topic for the development of covert channels. In this paper, a different type of collusion is discussed, where the parties colluding are not part of one team, but instead are multiple independent players, acting together in order to achieve a result that none of them are capable of achieving by themselves. Potential advantages and defences against collusion are discussed. Techniques designed for low-probability-of-intercept spread spectrum radio and multilevel secure systems are also applied in developing covert channels suitable for use in games. An example is given where these techniques were successfully applied in practice, in order to win an online programming competition. Finally, suggestions for further work are explored, including exploiting similarities between competition design and the optimisation of voting systems.