A general theory of security properties

We present a general theory of possibilistic security properties. We show that we can express a security property as a predicate that is true of every set containing all the traces with the same low level event sequence. Given this security predicate, we show how to construct a partial ordering of security properties. We also discuss information flow and present the weakest property such that no information can flow from high level users to low level users. Finally, we present a comparison of our framework and McLean's (1994) Selective Interleaving Functions framework.