1. A machine-implemented method, comprising: receiving a request that requires a privilege for a resource; wherein said resource is protected by at least two ACLs; wherein said at least two ACLs are associated with at least two ACL types, wherein among said at least two ACLs and said at least two ACL types, each ACL is associated with a different ACL type that is not associated any other ACL; determining that said privilege is not a member of an intersection set containing privileges that are common to all ACL types of said at least two ACL types; based on said determining that said privilege is not a member of an intersection set, denying said privilege for said request; and wherein the steps of determining and denying are performed by one or more computing devices.