Covert Ephemeral Communication in Named Data Networking

In the last decade, there has been a growing realization that the current Internet Protocol is reaching the limits of its senescence. This has prompted several research efforts that aim to design potential next-generation Internet architectures. Named Data Networking (NDN), an instantiation of the content-centric approach to networking, is one such effort. In contrast with IP, NDN routers maintain a significant amount of user-driven state. In this paper we investigate how to use this state for covert ephemeral communication (CEC). CEC allows two or more parties to covertly exchange ephemeral messages, i.e., messages that become unavailable after a certain amount of time. Our techniques rely only on network-layer, rather than application-layer, services. This makes our protocols robust, and communication difficult to uncover. We show that users can build high-bandwidth CECs exploiting features unique to NDN: in-network caches, routers' forwarding state and name matching rules. We assess feasibility and performance of proposed cover channels using a local setup and the official NDN testbed

Steganographic Timing Channels

This paper describes steganographic timing channels that use cryptographic primitives to hide the presence of covert channels in the timing of network traffic. We have identified two key properties for steganographic timing channels: (1) the parameters of the scheme should be cryptographically keyed, and (2) the distribution of input timings should be indistinguishable from output timings. These properties are necessary (although we make no claim they are sufficient) for the undetectability of a steganographic timing channel. Without them, the contents of the channel can be read and observed by unauthorized persons, and the presence of the channel is trivially exposed by noticing large changes in timing distributions – a previously proposed methodology for covert channel detection. Our steganographic timing scheme meets the secrecy requirement by employing cryptographic keys, and we achieve a restricted form of input/output distribution parity. Under certain distributions, our schemes conforms to a uniformness property; input timings that are uniformly distributed modulo a timing window are indistinguishable from output timings, measured under the same modulo. We also demonstrate that our scheme is practical under real network conditions, and finally present an empirical study of its covertness using the firstorder entropy metric, as suggested by Gianvecchio and Wang [8], which is currently the best published practical detection heuristic for timing channels