A formal approach for security evaluation

The authors discuss security issues and consider the extent to which internal relations among entities in a system should be taken into account when carrying out security analysis. They present a concrete and flexible security model expressed in terms of the internal relations in the system, rather than abstract state machines. Based on this model, security analysis can be carried out by decomposing the analysis of the whole system into analyses of subsets of the relations, and the security property of the whole system can be derived by composition of these secure relation subsets