Which of the following is NOT one of the five major elements of information security?

The five major elements of information security are widely recognized as confidentiality, integrity, availability, authenticity, and non-repudiation. Confidentiality ensures that sensitive information is accessed only by authorized individuals. Integrity guarantees that data is accurate and has not been tampered with. Availability ensures that information is accessible to authorized users when needed. Authenticity provides assurance that the data is genuine and from a legitimate source. Non-repudiation allows for accountability, ensuring that individuals cannot deny their actions related to data.

Efficiency, while important in the context of system performance and resource management, does not directly fall within the primary objectives of information security. Efficiency relates more to how well systems and processes operate rather than the protection of data and information systems. Thus, efficiency is not considered one of the core elements of information security, making it the correct answer to the question.