What refers to measures and controls taken to deny unauthorized persons access to U.S. Government information related to national security?

The term that refers to measures and controls taken to deny unauthorized access to U.S. Government information related to national security is information security. This encompasses the processes and practices designed to safeguard sensitive data and ensure that only authorized individuals have access to that information. Information security involves various strategies, including encryption, access controls, and security clearances, all focused on protecting classified and sensitive information vital to national defense.

Communications security, while closely related, specifically refers to protecting the transmission of information and ensuring that communications are not intercepted or compromised during relay. It is a subset of the broader field of information security. In contrast, operational security involves the processes designed to protect sensitive operations and activities from being discovered by adversaries. Data protection, though relevant in terms of safeguarding personal and sensitive data, does not specifically address the context of national security within U.S. Government operations. Thus, the correct concept in this scenario is information security.