Which of the following is the BEST method of maintaining the confidentiality of digital information?

Confidentiality, a core principle of information security, aims to prevent the unauthorized disclosure of information. The best method to maintain it involves a layered defense. Access controls authenticate and authorize users, file permissions define and enforce what authorized users can do with the data (e.g., read, write, execute), and encryption renders the data unreadable to anyone who bypasses the other controls. This combination provides the most robust and direct technical means of ensuring confidentiality.

B. Backups and business continuity planning are primary controls for maintaining the availability of information, not its confidentiality.
C. Logging, digital signatures, and write protection are primary controls for ensuring information integrity and supporting non-repudiation.
D. Awareness programs are administrative controls that support all security principles but are not the direct technical method for enforcing confidentiality.

1. ISACA, Cybersecurity Audit Certificate Program Study Guide, 2021, Domain 1: Cybersecurity and Audit Fundamentals, Section 1.2, defines the Confidentiality, Integrity, and Availability (CIA) triad, linking confidentiality to preventing unauthorized disclosure.

2. National Institute of Standards and Technology (NIST), Special Publication 800-53 Rev. 5, Security and Privacy Controls for Information Systems and Organizations, 2020, The Access Control (AC) family and the System and Communications Protection (SC) family (which includes encryption controls like SC-28) are foundational for preserving confidentiality.

3. MIT OpenCourseWare, 6.857 Computer and Network Security, Fall 2017, Lecture 1: Introduction & Threat Models, defines confidentiality and introduces cryptography and access control as its primary enforcement mechanisms.