Quantitative Evaluation of Enforcement Strategies

A security enforcement mechanism runs in parallel with a system to check and modify its run-time behaviour, so that it satisfies some security policy. For each policy, several enforcement strategies are possible, usually reflecting trade-offs one has to make to satisfy the policy. To evaluate them, multiple dimensions, such as security, cost of implementation, or cost of attack, must be taken into account. We propose a formal framework for the quantification of enforcement strategies, extending the notion of controller processes (mimicking the well-known edit automata) with weights on transitions, valued in a semiring.