Declassification
As shown previously, non-interference policy is too strict for use in most real-world applications. Therefore, several approaches to allow controlled releases of information have been devised. Such approaches are called information declassification.
Robust declassification requires that an active attacker may not manipulate the system in order to learn more secrets than what passive attackers already know.
Information declassification constructs can be classified in four orthogonal dimensions: What information is released, Who is authorized to access the information, Where the information is released, and When is the information released.
Read more about this topic: Information Flow (information Theory)