What is the portion of internal security that protects classified information in U.S. industry called?

The portion of internal security that protects classified information in U.S. industry is referred to as "industrial security." This aspect of security focuses specifically on safeguarding sensitive information related to government contracts and programs held by private industry entities. Industrial security incorporates various measures, including personnel security, physical security, and information security practices to ensure that classified data is properly managed and protected against unauthorized access or breaches.

In contrast, information security generally encompasses a broader category that includes protections for all types of data, whether classified or unclassified. Classified security may imply a focus on the management of classified information, but it is not a standardized term used in the industry. National security refers to the protection of a nation's interests as a whole, which includes but is not limited to industrial security.