Dynamic Noninterference: Consistent Policies, Characterizations and Verification
Sebastian Eggert, Henning Schnoor, Thomas Wilke · 2012
Abstract. We study non-interference based security in a dynamic set-ting, where the security policy may depend on the state of the sys-tem. More specifically, we 1. provide new definitions of dynamic non-interference security which conform to the intuitive notion of non-interference and give efficient algorithms to decide whether a given sys-tem is secure, and 2. obtain a characterization of secure systems using unwinding relations. Our new definitions are motivated by the fact that previous definitions show counter-intuitive behaviour, as we point out by exhibiting a system that is clearly insecure even though meeting the previous definition. We capture this deficiency by a precise study of con-sistency in dynamic policies. 1