200-201 Question 169
Select 3During a secure communication session between two parties, they decide to use the Diffie-Hellman (DH) key exchange to establish a shared secret. Which of the following statements correctly describes how the Diffie-Hellman key exchange process works?
- A
Both parties agree on a shared public base and modulus before exchanging information.
- B
Each party generates a private key and shares it directly with the other party.
- C
The shared secret is derived from the combination of each party's private key and the other party's public key.
- D
Diffie-Hellman provides encryption for the data being transmitted between the two parties.
- E
The shared secret generated by Diffie-Hellman can be used to derive symmetric encryption keys.
Show answer and explanation
Correct answers: A, C, E
Explanation
The Diffie-Hellman key exchange is a method used to securely establish a shared secret between two parties over an insecure channel. The process involves agreeing on public parameters, exchanging public keys, and using private keys to compute the shared secret. This shared secret can then be used to derive symmetric encryption keys for secure communication. However, Diffie-Hellman itself does not encrypt data; it is solely a key exchange mechanism.
- A. Correct.
Correct: The Diffie-Hellman key exchange process begins with both parties agreeing on a shared public base (g) and modulus (p), which are typically public values.
- B. Incorrect.
Incorrect: In Diffie-Hellman, private keys are never shared directly. Instead, each party generates a public key from their private key and the agreed upon public values.
- C. Correct.
Correct: Each party combines their private key with the other party's public key to calculate the shared secret.
- D. Incorrect.
Incorrect: Diffie-Hellman is a key exchange protocol and does not provide encryption for the data being transmitted.
- E. Correct.
Correct: The shared secret generated by Diffie-Hellman is commonly used to derive symmetric keys for encrypting communications.