What type of security does a system of policies and processes for protecting classified materials fall under?

The correct response relates to information security, which encompasses the policies, procedures, and practices that are implemented to protect sensitive information, including classified materials. Information security is vital for safeguarding both physical and digital assets from unauthorized access, disclosure, alteration, and destruction.

In the context of protecting classified materials, information security goes beyond just the technology and hardware; it encompasses the overall strategy for handling sensitive information, ensuring that it is accessed and managed only by individuals with the appropriate clearances and training. This includes establishing strict protocols for the classification, sharing, storage, and destruction of sensitive information to mitigate risks associated with potential leaks or breaches.

While other types of security, like computer security, focus specifically on protecting electronic systems and networks, or personnel security, which involves background checks and vetting individuals with access to sensitive information, information security provides a broad framework that includes all these elements in the context of safeguarding information as a whole. Consequently, the focus on classified materials specifically falls under the umbrella of information security, making this the appropriate answer.