What security concept is being applied when Larry and Fern must both present their own keys to enter the data center?

The correct choice is dual control, which is a fundamental security concept aimed at preventing unauthorized access and ensuring that no single individual can act independently to perform critical functions. In this scenario, the requirement for both Larry and Fern to present their own keys signifies that accessing the data center is a sensitive activity that necessitates the collaboration of multiple individuals. By requiring two separate keys—one from each person—the organization reduces the risk of unauthorized access, as one individual alone cannot gain entry.

Dual control is often implemented in environments that handle sensitive information or assets, ensuring that a checks-and-balances approach is adopted. This principle not only protects the assets but also promotes accountability among employees, as both must agree to an action before it can be executed.

The other concepts listed may relate to security practices in various ways but do not specifically address the requirement for two individuals to jointly control access, which is the essence of dual control. Defense in depth involves layering security measures to protect against various threats, segregation of duties aims to prevent fraud by dividing responsibilities among different individuals, and least privilege ensures that users have only the necessary permissions to perform their job functions. However, none of these concepts captures the essence of requiring dual participation for critical tasks like accessing a secure area.