Using coloured petri nets to simulate DoS-resistant protocols

In this work, we examine unbalanced computation between an initiator and a responder that leads to resource exhaustion attacks in key exchange protocols. We construct models for two cryp-tographic protocols; one is the well-known Internet protocol named Secure Socket Layer (SSL) protocol, and the other one is the Host Identity Protocol (HIP) which has built-in DoS-resistant mechanisms. To examine such protocols, we develop a formal framework based on Timed Coloured Petri Nets (Timed CPNs) and use a simulation approach provided in CPN Tools to achieve a formal analysis. By adopting the key idea of Meadows' cost-based framework and re¯ning the de¯nition of operational costs during the protocol execution, our simulation provides an accurate cost estimate of protocol execution compar- ing among principals, as well as the percentage of successful connections from legitimate users, under four di®erent strategies of DoS attack.

Impediments to Cosmopolitan Engagement: Technology and Late-Modern Cosmopolitanism

What characterises late modern variety of cosmopolitanism from its classical predecessors is the inherent connection between cosmopolitanism and technology. Technology enables a vital dimension of the cosmopolitan experience – to move beyond the cosmopolitan imagination to enable active, direct engagement with other cultures. Different types of technologies contribute to cosmopolitan practice but in this paper we focus on a specific set of these enabling technologies: technologies which play a crucial role in regulating the free movement of people and populations. We briefly examine how three of the great surveillance states of the 20th century – Nazi Germany, the Soviet Union, and the German Democratic Republic – used hightech solutions in pursuing an anti-cosmopolitanism. We suggest that in the period from 2001 to the present, important elements of the cosmopolitan ethos are being closed down, and once again high-tech is intimately connected to this moment. The increasing (and proposed) use of identity cards, biometric identification systems, ITS and GIS all work to make the globalised world much harder to traverse and inhibit the full expression and experience of cosmopolitanism. The result of these trends may be that the type of cosmopolitan sentiment exhibited in western countries is an ersatz, emptied out variety with little political-ethical robustness.