Understanding the TLS Handshake: The Secret Behind Your Secure Connection 🔒
When you visit a website, you may notice a little padlock icon next to the URL in your browser. This symbol signifies that your connection is secure, thanks to a process known as the TLS handshake. Today, we’ll delve into what this handshake entails and how it ensures that your data remains safe while browsing the internet.
For clarity, it may be beneficial to open an accompanying infographic that outlines the entire handshake process. View the infographic here for a clearer understanding as we go through the individual steps.
Setting the Stage: The Purpose of TLS
Before we explore the minutiae of the TLS handshake, it’s essential to recognize its two primary objectives:
- Authentication: To confirm that the server you are connecting to is indeed who it claims to be.
- Establishing Encryption Keys: To create session keys that will secure the data transferred between you and the server.
Additionally, two key concepts to keep in mind are that a “record” does not equate to a packet, and some basic cryptography knowledge will be helpful as we proceed.
Clarifying Terms
-
Records vs. Packets: In the context of TLS, records are the individual messages exchanged during the handshake. Sometimes multiple records can fit into a single packet, while a singular record may require several packets for transport.
-
Cryptographic Basics: Familiarity with concepts such as hashing, MACs (Message Authentication Codes), and encryption will enhance your understanding of the handshake process. For those who are not familiar with these terms, consider checking out introductory videos on each topic.
The TLS Handshake Process
1️⃣ Client Hello
The handshake begins with the “Client Hello” message, sent by your browser. This initial message includes five critical elements:
- SSL Version: The highest version of SSL/TLS supported by the client.
- Random Number: A unique set of random bytes for cryptographic purposes.
- Session ID: Used for session resumption, meaning it can speed up subsequent connections.
- Cipher Suites: A list of cryptographic algorithms the client supports.
- Extensions: Optional additional features that may enhance the handshake.
2️⃣ Server Hello
In response
Share this content:
