PFS depends on which type of following encryption?

A.
Symmetric

B.
Classic

C.
Secret

D.
Asymmetric

Explanation:
Perfect Forward Secrecy depends on asymmetric or public key cryptography and cannot be achieved with symmetric cryptography.

Answer option A is incorrect. Perfect Forward Secrecy cannot be accomplished via symmetric cryptography

Answer option C is incorrect. Remember that the security of any algorithm is not dependent on it being secret, merely upon the key being kept secret.

Answer option B is incorrect. Classic cryptography (such as the Caesar cipher, Vigenere cipher, etc.) is no longer used for secure communications.