When a message sent by a user is digitally signed with a private key, the person will not be able to deny sending the message. this application of encryption is an example of
a) authentication
b) nonrepudiation
c) confidentiality
d) auditing

b) Non-repudiation

Explanation: Non-repudiation is the factor that ensures that the user cannot deny something they have received or gained. This property makes sure that the authenticity is maintained by creating the security with assurance.

The user receives or sends the data with the private key/ signature that makes sure about the activity that user has done. Other options are incorrect because they don't provide the assurance without the denying .Thus, the correct option is option(b).