What designation is applied to information that could cause serious damage to national security?

The designation that is applied to information which could cause serious damage to national security is Secret. This classification indicates that unauthorized disclosure of this information could harm national security interests but is not as severe as the Top Secret category, where the potential damage is of an even greater magnitude.

In the classification system, information marked as Secret is carefully controlled because it requires strict access and dissemination protocols to prevent it from being disclosed to individuals who do not have the appropriate security clearance. Conversely, information classified as Top Secret is reserved for the most sensitive information, where the expected damage from unauthorized disclosure is exceptionally high. The term "Classified" is a broader category that includes both Secret and Top Secret designations but does not provide the specific context of the severity of the damage. Public information, on the other hand, poses no risk to national security and is accessible to anyone. This distinction emphasizes the importance of maintaining the appropriate levels of security for the various types of information in relation to national security threats.