Information sensitivity is the control of access to information or knowledge that might result in loss of an advantage or level of security if disclosed to others who might have low or unknown trustability or undesirable intentions.

Loss, misuse, modification or unauthorized access to sensitive information can adversely affect the privacy or welfare of an individual, trade secrets of a business or even the security, internal and foreign affairs of a nation depending on the level of sensitivity and nature of the information.

The term classified information generally refers to information that is subject to special security classification regulations imposed by many national governments. The term "Unclassified" as used in the below refers to information that is not subject to security classification regulations. Information can be reclassified to a different level or declassified (made available to the public) depending on changes of situation or new intelligence.

This refers to information that is already a matter of public record or knowledge.