Cybersecurity: Things I Wish I'd Known - Part 1

I have a hardware engineering background but cybersecurity is a field that fundamentally grew out of networking.  So when I made the transition into cybersecurity there were a few things I had to learn "on the job".  Not knowing these things didn't prevent me from getting into cybersecurity but, had I known them ahead of time, it would have made my transition into cybersecurity much easier.  The is is the first part in a series of posts about things I wish I'd known.  Enjoy.

The Three-Way Handshake: SYN, ACK, SYN/ACK - The Building Blocks of Reliable Communication

In the realm of computer networking, the Three-Way Handshake plays a pivotal role in establishing connections between devices over a network. This fundamental process is crucial for reliable communication and forms the foundation of modern internet protocols. In this blog post, we will delve into the mechanics of the Three-Way Handshake, its creators, and why it remains an essential concept in computer networking.

What is the Three-Way Handshake?

The Three-Way Handshake is a method used by devices to establish a reliable connection, particularly in Transmission Control Protocol (TCP) communication. TCP is a connection-oriented protocol, and this handshake ensures that both the sender and the receiver are ready to exchange data securely and accurately.

The Three-Way Handshake consists of three steps, aptly represented by the abbreviations SYN, ACK, and SYN/ACK:

1. SYN (Synchronize): The process begins with the initiating device (usually the client) sending a SYN packet to the destination device (usually the server) to request a connection.
2. ACK (Acknowledgment): The destination device responds with an ACK packet, acknowledging the SYN request.
3. SYN/ACK (Synchronize/Acknowledge): Finally, the initiating device sends a SYN/ACK packet, confirming the acknowledgement of the connection.

Once the Three-Way Handshake is complete, a reliable connection is established, and data transmission can occur between the devices.

The Inventors of the Three-Way Handshake

The Three-Way Handshake, as we know it today, was primarily developed by Dr. Vint Cerf and Dr. Robert E. Kahn in the early 1970s. Dr. Vint Cerf and Dr. Robert E. Kahn are often referred to as the "Fathers of the Internet" for their groundbreaking work in co-inventing TCP/IP protocols.

In 1974, Cerf and Kahn published a paper titled "A Protocol for Packet Network Intercommunication," which outlined the design of the TCP protocol and introduced the concept of the Three-Way Handshake. Their work laid the groundwork for modern internet communication and revolutionized the way devices connect and exchange data.

The Importance of the Three-Way Handshake

The Three-Way Handshake serves several critical purposes that make it vital in the world of computer networking:

1. Connection Establishment: By performing the Three-Way Handshake, devices ensure that the other party is available and responsive before starting data transmission. This process minimizes the chances of data loss and enhances the reliability of the connection.
2. Reliable Communication: The SYN, ACK, and SYN/ACK packets provide a mechanism to synchronize sequence numbers and acknowledge the reception of packets. This guarantees that data is transmitted accurately and in the correct order, reducing the risk of errors or corruption during transmission.
3. Flow Control: During the handshake process, the two devices negotiate the size of the data packets they can handle. This flow control mechanism prevents overwhelming the receiving device with more data than it can process efficiently, ensuring smoother data transmission.
4. Connection Termination: The Three-Way Handshake also facilitates the graceful termination of a connection. When both parties have finished exchanging data, they exchange special packets to signal the closure of the connection correctly.
5. Security and Authentication: The handshake process can also be extended to include security measures, such as cryptographic keys or certificates, to establish secure connections, commonly known as SSL/TLS handshakes.

In conclusion, the Three-Way Handshake, with its SYN, ACK, and SYN/ACK packets, has been a crucial invention in the world of computer networking. Thanks to the pioneering work of Dr. Vint Cerf and Dr. Robert E. Kahn, this process has become a cornerstone of modern internet communication. The Three-Way Handshake's ability to establish reliable connections, facilitate secure communication, and ensure orderly data transmission has allowed the internet to grow and thrive into the global network we depend on today.