The marketing department at Company A regularly sends out emails signed by the company's Chief Executive Officer (CEO) with announcements about the company. The CEO sends company and personal emails…

Identity proofing is the process of verifying a user's identity during enrollment, not a mechanism for proving message origin after the fact during legal proceedings.

Non-repudiation ensures that a sender cannot deny sending a message by binding the message to their unique private key through a digital signature that only they could produce. Since the corporate PKI issues one certificate per user and the CEO did not share their password, only the CEO could have used the private key associated with their certificate to sign emails. Any email bearing a valid signature from the CEO's certificate was definitively sent from the CEO's account, distinguishing it from unsigned marketing department emails.

Key escrow is a mechanism for storing copies of cryptographic keys for recovery purposes and does not itself prove who signed or sent a specific email.

Digital rights management controls how content is accessed and distributed after creation but does not provide cryptographic proof of message origin or authorship.