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

14.3 The AES block cipher

In stark contrast to the DES algorithm, whose design criteria were never fully published, the AES was conceived in a very transparent process. After a formal, worldwide Call for Algorithms published in 1997 by the NIST, the National Institute of Standards and Technology in the United States, 15 candidate algorithm specifications were submitted, along with reference implementations in C and Java. The goal was to find a block cipher that was as secure as Triple-DES, but much more efficient. More specifically, the AES should have a block length of 128 bits and should be able to support variable key lengths of 128, 192, and 256 bits. Further selection criteria, apart from security, were as follows:

  • Versatility: The selected algorithm should perform uniformly well on all hardware platforms, ranging from chip cards over PCs to Application-Specific Integrated Circuits(ASICs) and Field Programmable Gate Arrays (FPGAs).

  • Key agility: It should be possible to switch to...