Final answer:
Authentication is the correct term for the process of determining if a computer user is who they claim to be, which involves verifying their identity through credentials.
Step-by-step explanation:
Determining that a computer user really is who they claim to be is called authentication. This process ensures that an individual is granted access only after successfully presenting evidence, or credentials, to prove their identity. This is different from authorization, which determines what an authenticated user is allowed to do, and encryption, which involves encoding messages to protect them from being read by unauthorized parties. The option of authorization pertains to the rights and privileges granted to an individual, and is not directly concerned with verifying identity. Encryption is more about maintaining confidentiality and integrity of data rather than confirming user identity. Validation can mean various things in different contexts, but when it comes to user identity, it is typically part of the authentication process.