Which of the following provides the GREATEST assurance of message authenticity?

A. The prehash code is derived mathematically from the message being sent.

B. The prehash code is encrypted using the senders private key.

C. The prehash code and the message are encrypted using the secret key.

D. The sender attains the recipients public key and verifies the authenticity of its digital certificate with a certificate authority.

Explanation:

Encrypting the prehash code using the senders private key provides assurance of the authenticity of the message. Mathematically deriving the prehash code provides integrity to the message. Encrypting the prehash code and the message using the secretkey provides confidentiality.