Certified Ethical Hacker (CEH v11) — Question 196

Dorian is sending a digitally signed email to Poly. With which key is Dorian signing this message and how is Poly validating it?

Answer options

• A. Dorian is signing the message with his public key, and Poly will verify that the message came from Dorian by using Dorian's private key.
• B. Dorian is signing the message with Poly's private key, and Poly will verify that the message came from Dorian by using Dorian's public key.
• C. Dorian is signing the message with his private key, and Poly will verify that the message came from Dorian by using Dorian's public key.
• D. Dorian is signing the message with Poly's public key, and Poly will verify that the message came from Dorian by using Dorian's public key.

Correct answer: C

Explanation

The correct answer is C because Dorian uses his private key to sign the message, which ensures that only he could have signed it. Poly then uses Dorian's public key to verify the signature, confirming the message's authenticity. The other options incorrectly use the keys, leading to a misunderstanding of the public/private key mechanism in digital signatures.