Session privacy enhancement by traffic dispersion

Traditional network routing uses the single (shortest) path paradigm. This paradigm leaves the session vulnerable to a variety of security threats, such as eavesdropping. We propose to overcome this via dispersive routing, conducted over multiple paths. This increases significantly the costs inflicted on an attacker who wishes to eavesdrop sessions by hijacking network links (or routers). We formulate the Security Traffic Manager (STM) problem (route session fragments¹, over multiple paths, so that protection against an attacker, with a known hijacking budget, is guaranteed) and the attacker problem (find the cheapest hijacking strategy). The problems are analyzed for cases in which the attacker must eavesdrop all the fragments as well for cases in which it must eavesdrop only a fraction of them. We analyze the theoretical complexity of these problems and offer algorithms for finding dispersive routes that guarantee security. Though some theoretical cases of the problem are shown to be NP-Hard, typical practical cases can be solved by polynomial time algorithms. We extend the STM problem to more practical situations where the goal of the STM is to guarantee privacy, using minimal number of limited-length paths. The algorithms are tested through simulation and shown to be efficient in many scenarios. The model and algorithms offered in this study can be used for deploying a "session enhanced security" service in packet networks².