The lattice model proposed by Denning in her seminal work provided secure information flow analyses with an intuitive and uniform mathematical foundation. Different organisations, however, may employ quite different security lattices. In this paper, we propose a connection framework that permits different organisations to exchange information while maintaining both security of information flows as well as their autonomy in formulating and maintaining security policy. Our prescriptive framework is based on the rigorous mathematical framework of Lagois connections given by Melton, together with a simple operational model for transferring object data between domains. The merit of this formulation is that it is simple, minimal, adaptable and intuitive, and provides a formal framework for establishing secure information flow across autonomous interacting organisations. We show that our framework is semantically sound, by proving that the connections proposed preserve standard correctness notions such as non-interference.
Abstract In this paper we define a Lagois connection, which is a generalization of a special type of Galois connection. We begin by introducing two examples of Lagois connections. We then recall the definition of Galois connection and some of its properties; next we define Lagois connection, establish some of its properties, and compare these with properties of Galois connections; and then we (further) develop examples of Lagois connections. Via these examples it is shown that, as is the case of Galois connections, there is a plethora of Lagois connections. Also it is shown that several fundamental situations in computer science and mathematics that cannot be interpreted in terms of Galois connections naturally fit into the theory of Lagois connections. We study frameworks for the equivalence of abstract state-transition systems represented as posets. A basic notion of equivalence is proposed. A least fix-point operator transforms basic equivalences into strong equivalences (=Lagois Connections) which makes Lagois Connections into a category. In the absence of divergence, the two notions of equivalence coincide. We generalize these notions by adding a logical level to express divergence more precisely. Then both generalized notions of equivalence coincide even in the presence of divergence.