VARIACIONES SRAFFIANAS: HOMENAJE A ERNEST LLUCH

No era Ernest Lluch individuo propenso a adoptar un singular libro de cabecera, ni a seguir con fidelidad las huellas de un único maestro. Pero, por supuesto, tenía su personal esquema devalores y sus escalas de preferencias. Y uno de los autores que sin discusión estaba presente en su galería privada de economistas ilustres fue Piero Sraffa (1898-1983). Creo que también habríacolocado en esa división de honor a François Quesnay, Adam Smith, David Ricardo, Karl Marx, Knut Wicksell, John M. Keynes, Joseph A.Schumpeter, Maurice H. Dobb, Wassily Leontief, John K. Galbraith, Paolo Sylos Labini y Albert O. Hirschman.

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.

Security and legal issues in E-tendering

The Queensland Department of Public Works (QDPW) and the Queensland Department of Main Roads (QDMR) have identified a need for industry e-contracting guidelines in the short to medium term. Each of these organisations conducts tenders and contracts for over $600 million annually. This report considers the security and legal issues relating to the shift from a paper-based tendering system to an electronic tendering system. The research objectives derived from the industry partners include: • a review of current standards and e-tendering systems; • a summary of legal requirements impacting upon e-tendering; • an analysis of the threats and requirements for any e-tendering system; • the identification of outstanding issues; • an evaluation of possible e-tendering architectures; • recommendations for e-tendering systems.