Security modelling

The author describes a technique referred to as security modelling which, although it does not set out with the same aims as risk analysis, has wide applications in the study of risk, is much simpler to use, and is more general. The technique is based around a software tool and draws upon ideas from reliability engineering, risk analysis and spreadsheets. Its main features are: it places the user in the active role; it enables models of the security features of an organisation to be built and freely experimented upon; it automatically uncovers all possible destructive combinations of events implied by the model, including those not foreseen by the user; it unifies into a single concept the notions of asset, threat, vulnerability and countermeasure; and it enables joint optimisation of cost and effectiveness