If the authenticator is encrypted with the sender's private key, it
serves as a signature that verifies origin, content, and sequencing.

Question

Quizplus · Accepted Answer

Encrypting the authenticator with the sender's private key allows anyone with the corresponding public key to decrypt it, verifying that it was indeed the sender who encrypted it (authenticating origin), and since the authenticator is based on the content and sequencing, it also verifies those aspects. This process is essentially what defines a digital signature.

If the Authenticator Is Encrypted with the Sender's Private Key