Question 18

Non-repudiation ensures that a user cannot deny sending an email.

Non-repudiation is a security concept that guarantees that a sender cannot deny having sent a message, which is achieved through mechanisms like digital signatures. This concept provides proof of the origin and integrity of the message, thereby affirming that the sender is indeed who they claim to be.

A) Non-repudiation

This option correctly identifies the security concept that prevents the sender from denying the act of sending the email. By utilizing a digital signature, the sender provides undeniable proof of their identity, ensuring that they cannot refute their involvement in transmitting the message.

B) Confidentiality

Confidentiality refers to the protection of information from unauthorized access. While it ensures that only intended recipients can read the email, it does not provide any proof of the sender's identity or prevent them from denying the act of sending the message.

C) Integrity

Integrity involves ensuring that the content of the message has not been altered during transmission. Although it is important for verifying that the information remains unchanged, it does not address the sender's ability to deny sending the email.

D) Authentication

Authentication is the process of verifying the identity of a user or system. While it can help confirm that the sender is who they claim to be at the moment of sending, it does not provide the same level of irrevocable proof as non-repudiation, which specifically prevents denial of sending the email.

Conclusion

Non-repudiation is the only concept among the options that directly addresses the need for a sender to be unable to deny sending an email, making it the correct answer. Other options, while related to security, focus on different aspects such as confidentiality, integrity, and authentication, which do not provide the same assurance against denial of sending.