If information is still, after 25 years, valid and describes a security measure of a building, facility, system or method or it is still part of a plan used for national defence or civil defence, it remains non-open as long as the information is pertinent for the purpose. The same indefinite non-openness applies to all documents under international security obligations, if the release might still affect Finnish foreign relations negatively. The non-openness of other documents may be prolonged up to 55 years by the Council of State, if necessary to safeguard a protected interest.