to view some classified information, and how it must be stored, transmitted, and destroyed. Additionally, access is restricted on a "need to know" basis. Simply possessing a clearance does not automatically authorize the individual to view all material classified at that level or below that level. The individual must present a legitimate "need to know" in addition to the proper level of clearance. Compartmented information In addition to the general risk-based classification levels, additional compartmented constraints on access exist, such as (in the U.S.) Special Intelligence (SI), which protects intelligence sources and methods, No Foreign dissemination (NoForn), which restricts dissemination to U.S. nationals, and Originator Controlled dissemination (OrCon), which ensures that the originator can track possessors of the information. Information in these compartments is usually marked with specific keywords in addition to the classification level. Government information about nuclear weapons often has an additional marking to show it contains such information (CNWDI). International When a government agency or group shares information between an agency or group of other country's government they will generally employ a special classification scheme that both parties have previously agreed to honour. For example, the marking Atomal, is applied to U.S. Restricted Data or Formerly Restricted Data and United Kingdom Atomic information that has been released to NATO. Atomal information is marked COSMIC Top Secret Atomal (CTSA), NATO Secret Atomal (NSAT), or NATO Confidential Atomal (NCA). BALK and BOHEMIA are also used. NATO classifications For example, sensitive information shared amongst NATO allies has four levels of security classification; from most to least classified: COSMIC Top Secret (CTS) NATO Secret (NS) NATO Confidential (NC) NATO Restricted (NR) A special case exists with regard to NATO Unclassified (NU) information. Documents with this marking are NATO property (copyright) and must not be made public without NATO permission. COSMIC is an acronym for "Control Of Secret Material in an International Command". International organizations The European Union has four levels: EU Top Secret, EU Secret, EU Confidential, EU Restricted. (Note that usually the French terms are used.) Très Secret UE/EU Top Secret: information and material the unauthorised disclosure of which could cause exceptionally grave prejudice to the essential interests of the European Union or of one or more of the Member States; Secret UE/EU Secret: information and material the unauthorised disclosure of which could seriously harm the essential interests of the European Union or of one or more of the Member