Free CompTIA Security+ SY0-601 Practice Question

Elliptic Curve Diffie-Hellman Ephemeral (ECDHE) is the correct answer because it allows for Perfect Forward Secrecy (PFS) by generating new keys for each session that are not based on the server's long-term private key; therefore, compromising the server's private key does not allow past sessions to be decrypted. Static RSA does not support PFS since session keys are derived and encrypted with the server's long-term key, implying potential future compromise. ECDH (without the 'Ephemeral') would be incorrect because, without the ephemeral component, some implementations might use fixed keys, thereby risking the exposure of session keys if the long-term private key is compromised. SSL with PFS as an answer choice is a distraction because SSL is a protocol that can use many types of key exchanges, and PFS is a property of specific key exchange mechanisms, not a protocol in itself.