the steps mentioned below.

• The client first communicates with the server by sending a Hello message. The message includes a number of options that are to be used in the communication, such as the version of the protocol to be used, CipherSuites supported by the client, compression methods, and a 32-byte random number.
• The server replies to the Hello message and makes choices about the options to be used, like the version of the protocol, CipherSuite, and compression method. It also fills up the SessionID and replaces the 32-byte random number with the date and timestamp.
• The server now sends its digital certificate to the client (What is a digital certificate?). This digital certificate contains the public key of the server.
• The client verifies the digital certificate with the CA or Certificate Authority. (How does a digital certificate get verified?)
• After the digital certificate is verified, the client starts to negotiate the symmetric key. (Why does the TLS protocol use symmetric key encryption?) There are a number of algorithms it can use. One example is the Diffie-Hellman Key Exchange Algorithm (How does the Diffie-Hellman Key Exchange Protocol work?). Please note that at this point, a secure connection is not yet established. So, the symmetric key cannot be exchanged between the server and the client directly. Hence, key exchange algorithms like the Diffie-Hellman Key Exchange Protocol are used. The client also signs the message and sends the MAC or Message Authentication Code to the Server. (What is a Message Authentication Code (video)?)
• The server processes the key exchange parameters. It also checks the MAC or Message Authentication Code to verify the integrity and authenticity of the message sent.
• If everything goes well, a secure TLS connection is established between the server and the client. And sensitive data gets transferred over the secure connection.

The article gives a brief overview of the TLS protocol. Interested readers who want to know more about how different cryptographic algorithms work and how they are used in various secure network protocols may want to refer to the book “Cryptography And Public Key Infrastructure.”

Security Fundamentals Practice Tests

The Security Fundamentals Practice Tests test one’s fundamental knowledge of cyber security. The practice tests are good for those who are preparing for various certification exams like the CCNA, CCNP, or CompTIA. They are also good for students and IT/security professionals who want to improve their understanding of cybersecurity.