A Definition of Secure Dependencies Using the Logic of Security

In the context of the modal logic of security, conden-tiality is dened by the formula K B ' ! R B ' that could be read \ If B knows ' then B should have the permission to know '". We propose a new semantics for the R B modal operator, such that the denition of security would allow a certain number of dependencies (called secure dependencies) between objects of the system. We formally compare this new denition of security with non-interference, non-deducibility and generalized non-interference, especially with respect to assumptions on the systems as non-determinism and input-totalness.