Which classification refers to highly sensitive data that is restricted to trusted individuals?

The classification that refers to highly sensitive data restricted to trusted individuals is indeed classified as "Top Secret." This classification is used in various contexts, including government and military, to denote information that could cause exceptionally grave damage to national security if disclosed. Individuals who have access to Top Secret information must be thoroughly vetted and granted security clearances to ensure that they are trusted to handle such sensitive data responsibly.

In the context of data classification, the other classifications are generally less restrictive in terms of the sensitivity and the potential impact of unauthorized disclosure. For instance, "Classified" information can encompass various levels of sensitivity and may not necessarily imply a very limited access requirement. "Secret" refers to information that is sensitive but does not reach the same level of criticality as Top Secret. "Data Tag" is not a formal classification but rather a mechanism used for indicating classification levels within datasets.

Understanding these distinctions is important for managing and protecting sensitive information, ensuring that appropriate security measures are in place based on the classification level.