Determine if confidentiality policies contain contradictions

[Marc Storm Larsen]

Due to inheritance in confidentiality policies, it can be that some policies will contradict each other, thus making it impossible to satisfy the policies and thereby accessing the data resource and all other resources that would have had a dependency to it.

If a contradiction is determined/discovered as soon as it occur, the "branch" in the data repository can be closed.

An example of two contradicting policies could be that resource r1 has the policy
phi1 := [] (author = john)
and resource r2 has
phi1 := [] (author != john)
Say that r2 has an dependency to r1, thus inheriting the policy of r1, it is clear that the two policies can't be satisfied.