Which protocol is commonly used to negotiate keys securely in a TLS handshake?

• A. RSA or Diffie-Hellman Ephemeral (DHE)
• B. Public-key algorithms such as RSA or Diffie-Hellman Ephemeral (DHE) are used to securely negotiate keys.
• C. TLS does not negotiate keys; keys are fixed.
• D. Hashes are used to negotiate keys.

Answer: (B)

In TLS, the session keys are established through a key-exchange process that uses public-key cryptography. During the handshake, the client and server leverage public-key algorithms to agree on a shared secret that is then used to derive the symmetric keys for the session. RSA-based key exchange encrypts a pre-master secret with the server’s public key, while Diffie-Hellman Ephemeral (DHE) allows both sides to compute a common secret without sending it, providing forward secrecy. This is why using public-key algorithms such as RSA or DHE to securely negotiate keys is the correct idea. TLS does not rely on fixed keys, and hashes are not used to negotiate keys; hashes serve integrity checks within the protocol.