The most effective strategy among the choices to prevent cheating is the implementation of secure user authentication protocols. Cheating, in the context of an LMS, often involves impersonation, where one individual takes an exam or completes coursework for another. Secure authentication mechanisms, such as multi-factor authentication (MFA) or biometrics, provide a higher assurance of the user's identity. By verifying that the person logging in and interacting with the system is the legitimate student, these protocols directly mitigate the risk of identity-based cheating and uphold academic integrity by ensuring non-repudiation for submitted work.

A. Enforcement of a strict firewall policy is a network-level control that protects the server from unauthorized external access but does not prevent cheating by an already authenticated user.

B. Disabling Bluetooth is a limited, endpoint-specific control that only addresses a narrow method of cheating (e.g., using wireless earpieces) and can be easily bypassed.

D. Regular software updates and patch management are crucial for protecting the system from technical exploits but do not address user-level actions like impersonation or collusion.

1. NIST Special Publication 800-53 Revision 5, "Security and Privacy Controls for Information Systems and Organizations." The Identification and Authentication (IA) control family is designed to "identify and authenticate organizational users." The discussion for control IA-2, "Identification and Authentication (Organizational Users)," emphasizes the necessity of verifying a user's identity before granting access, which is the foundational principle for preventing impersonation. (See: NIST SP 800-53 Rev. 5, Chapter 3, IA Control Family).

2. Saltzer, J. H., & Schroeder, M. D. (1975). "The Protection of Information in Computer Systems." This foundational paper in computer security, often cited in university curricula, outlines the principle of complete mediation, which requires that every access to every object be checked for authority. This process begins with reliable authentication to establish the identity of the subject (the student). An LMS must first know who the user is before it can grant access to an exam. (See: Section I.A.3, "Design Principles"). Available via MIT's DSpace.

3. Garrison, G., & R.O. Briggs. (2012). "A Framework for Discovering and Mitigating the Security Risks in E-Learning Systems." In this peer-reviewed article, the authors identify impersonation as a key security risk in e-learning. They state, "Authentication mechanisms are the first line of defense against many security threats... Strong authentication can help to mitigate the risk of impersonation." This directly links secure authentication to the prevention of a primary form of cheating. (See: Proceedings of the 45th Hawaii International Conference on System Sciences, p. 115). DOI: 10.1109/HICSS.2012.493.