What security approach is best characterized by the principle of requiring control, authentication, and authorization for all activities by all users?

The Zero Trust Model is characterized by the principle of requiring control, authentication, and authorization for all activities conducted by all users, regardless of their location within or outside the organization's network perimeter. This security approach operates under the assumption that threats could be present both outside and inside the network.

In the Zero Trust Model, every access request is thoroughly verified before granting access to resources. This involves continuous monitoring and validation of user identities and device trustworthiness, ensuring that no implicit trust is given to any user or device. Each interaction is treated as untrusted until proven otherwise, which strengthens the overall security posture of an organization against a range of cyber threats.

The other choices represent different security concepts that do not encompass the same holistic and stringent principles of access controls that the Zero Trust Model embodies. For instance, Access Control Lists are primarily a means of specifying permissions for individual users or groups on network resources but do not inherently involve the comprehensive, ongoing verification of all users and activities that the Zero Trust Model does. Public Key Infrastructure focuses on the establishment of a secure method for exchanging encryption keys, while an Intrusion Detection System is designed to monitor and analyze the network for suspicious activities rather than enforcing stringent control over all access requests.