CoCo: Coding-based covert timing channels for network flows

In this paper, we propose CoCo, a novel framework for establishing covert timing channels. The CoCo covert channel modulates the covert message in the inter-packet delays of the network flows, while a coding algorithm is used to ensure the robustness of the covert message to different perturbations. The CoCo covert channel is adjustable: by adjusting certain parameters one can trade off different features of the covert channel, i.e., robustness, rate, and undetectability. By simulating the CoCo covert channel using different coding algorithms we show that CoCo improves the covert robustness as compared to the previous research, while being practically undetectable.