How proof that a message originated from a specific party

C I A triad

Nonrepudiation is the ability to have proof that a message originated from a specific party. In an email system, for example, nonrepudiation mechanisms ensure that every message can be confirmed as coming from a specific party or sender.

Answer the following question(s):

1. Do you think nonrepudiation falls under one of the tenets of the C-I-A triad (confidentiality, integrity, and availability)? Why or why not?
2. Is the C-I-A triad adequate when selecting controls for a Windows system? Why or why not?