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

11.1 The need for authenticity and integrity

Imagine Alice being a control computer in a train control system and Bob being a board computer installed within a train. For a more realistic scenario, let’s assume the train control system is a positive train control. This means that the train is only allowed to move if it receives an explicit move message from the train control. Otherwise, the train does not move.

Further, assume that there are two different move messages that onboard computer Bob can receive from control computer Alice:

  • Message ms instructing the train to move slowly, for example, before entering a train station

  • Message mf instructing the train to move fast

In addition, to secure the train control against cyberattacks, the communication channel between Alice and Bob is protected using a cryptographic mechanism that provides confidentiality only. That is, Alice and Bob share a secret key k and can compute an encryption function ek to make their communication unintelligible...