Question

John recently received an email message from Bill. What cryptographic goal would need to be met to convince John that Bill was actually the sender of the message?

A. Availability
B. Confidentiality
C. Integrity
D. Nonrepudiation

Answer 1

The cryptographic goal required is nonrepudiation, which ensures that the sender cannot deny sending an email. This is achieved via digital signatures that validate the origin of the message.

Step-by-step explanation:

The cryptographic goal that needs to be met to convince John that Bill was actually the sender of the email message is nonrepudiation. Nonrepudiation ensures that a sender cannot deny the validity of the message they sent, providing proof of origin. This can be achieved through digital signatures, where Bill would use his private key to sign the message, and John would use Bill's public key to verify the signature. If the verification is successful, John can be confident that the message was indeed sent by Bill and has not been altered, as the integrity of the message is tied to the digital signature as well.