A security administrator is implementing encryption on all hard drives in an organization. Which of the following security concepts is the administrator applying?

Integrity refers to the assurance that data is accurate and unaltered during storage or transmission. While encryption can support data integrity by preventing unauthorized modifications, it primarily focuses on keeping data confidential. Therefore, integrity is not the main concept being applied in this scenario.

Authentication is the process of verifying the identity of users or systems before granting access to resources. Although it is essential for securing access to encrypted data, it does not pertain directly to the act of encrypting data itself. Thus, authentication does not represent the primary security concept involved in the administrator's action.

Zero Trust is a security framework that operates on the principle of "never trust, always verify," regardless of the user's location within or outside the network. While adopting a Zero Trust model may involve encryption as part of a broader security strategy, the specific action of encrypting hard drives is primarily focused on protecting data confidentiality.