Book Image

TLS Cryptography In-Depth

By : Dr. Paul Duplys, Dr. Roland Schmitz
Book Image

TLS Cryptography In-Depth

By: Dr. Paul Duplys, Dr. Roland Schmitz

Overview of this book

TLS is the most widely used cryptographic protocol today, enabling e-commerce, online banking, and secure online communication. Written by Dr. Paul Duplys, Security, Privacy & Safety Research Lead at Bosch, and Dr. Roland Schmitz, Internet Security Professor at Stuttgart Media University, this book will help you gain a deep understanding of how and why TLS works, how past attacks on TLS were possible, and how vulnerabilities that enabled them were addressed in the latest TLS version 1.3. By exploring the inner workings of TLS, you’ll be able to configure it and use it more securely. Starting with the basic concepts, you’ll be led step by step through the world of modern cryptography, guided by the TLS protocol. As you advance, you’ll be learning about the necessary mathematical concepts from scratch. Topics such as public-key cryptography based on elliptic curves will be explained with a view on real-world applications in TLS. With easy-to-understand concepts, you’ll find out how secret keys are generated and exchanged in TLS, and how they are used to creating a secure channel between a client and a server. By the end of this book, you’ll have the knowledge to configure TLS servers securely. Moreover, you’ll have gained a deep knowledge of the cryptographic primitives that make up TLS.
Table of Contents (30 chapters)
1
Part I Getting Started
8
Part II Shaking Hands
16
Part III Off the Record
22
Part IV Bleeding Hearts and Biting Poodles
27
Bibliography
28
Index

6.5 TLS version 1.2

While we are largely focusing on TLS version 1.3 in this book, it is also instructive to take a look at version 1.2. Firstly, there are still many TLS servers that do not support version 1.3. Secondly, and more importantly, TLS version 1.2 and TLS version 1.3 share the same basic architecture. In particular, the basic steps in the so-called handshake protocol are the same but can be better explained in the context of TLS version 1.2, which is a bit less dense than the TLS version 1.3 handshake.

6.5.1 Subprotocols in TLS version 1.2

TLS version 1.2 consists of several subprotocols. Their location within the internet protocol stack and their relation to each other are shown in Figure 6.4.

Figure 6.4: TLS subprotocols

Figure 6.4: TLS subprotocols

  • Handshake protocol: This protocol is invoked when the client and server meet for the first time or if they want to resume an earlier session. In the former case, they need to agree on a set of algorithms that protect the channel between them...