A comparison of semantic models for intransitive noninterference⋆

Noninterference is a notion of information flow security, originally defined for transitive information flow policies. A number of different definitions of noninterference have been proposed for intransitive policies. These definitions are stated with respect to several different semantic models, including state machines with observations on states, state machines with outputs associated to actions, and process algebras. The paper studies the relationship between these definitions and models. Several mappings are defined that transform one semantic model into another, and the correspondences between the definitions under these mappings are precisely characterized. In particular, the paper considers definitions of intransitive noninterference due to Haigh and Young (1987), Roscoe and Goldsmith (1999) and van der Meyden (2007).