Which message begins the TLS handshake from the client?

• A. Finished
• B. Server Hello
• C. Certificate
• D. Client Hello

Answer: (D)

TLS handshakes begin with the client sending a ClientHello to start the negotiation. This message asks for things like the protocol version the client supports, a list of cipher suites it can use, compression methods, and some random data to help generate keys. It may also include extensions such as SNI to identify the hostname the client is connecting to.

After that, the server replies with ServerHello, deciding on the version and cipher suite to use and providing its own random data. The server then sends its certificate in a Certificate message to prove its identity. The handshake continues with additional messages to finish key exchange and verification, culminating in a Finished message once the secure keys are in place. Because the client’s ClientHello starts the process, it is the message that begins the TLS handshake.