Which principle of the CIA triad does this support?

Availability refers to ensuring that information and resources are accessible to authorized users when needed. While important for system functionality, it does not focus on protecting sensitive data from unauthorized access, which is the core aspect being supported in this scenario.

Integrity involves maintaining the accuracy and consistency of data over its lifecycle. Although integrity is crucial for ensuring that information remains unaltered by unauthorized entities, it does not specifically address the protection of data from unauthorized access or disclosure, which is the focus of this question.

Authentication is the process of verifying the identity of users before granting access to systems or data. While it is a necessary step to ensure confidentiality, authentication itself does not represent the principle of protecting information from unauthorized access; rather, it is a means to achieve confidentiality.