amorphous.

Defense strategy 2 – dining steganographers
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Our second defensive strategy is more sophisticated, and is inspired by the theory of anonymous communication as developed by computer scientists, most notably Chaum [@Chaum88]. A node that acquires a high vertex order, and thus could be threatened by a vertex-order attack, splits itself into $n$ nodes, arranged in a ring. The rings have two functions. First, they provide resilience: a ring broken at one point still supports communications between all its surviving nodes, and it is the simplest such structure. Second, nodes can route covert traffic between appropriate input and output links, and use encryption and other information-hiding mechanisms to conceal the traffic. This model was originally presented in Chaum’s seminal ‘dining cryptographers’ paper cited above, so we might refer to it as the ‘dining steganographers’. The collaborating nodes in each ring cannot conceal the existence of communication between them, as the cover traffic is visible to the attacker. However, from the attacker’s viewpoint it is not obvious that these $n$ nodes are acting as a virtual supernode.

Our focus here is on the effects of network topology, rather than on the higher-layer mechanisms that actually implement the covertness property and 