Book Image

Demystifying Cryptography with OpenSSL 3.0

By : Alexei Khlebnikov
Book Image

Demystifying Cryptography with OpenSSL 3.0

By: Alexei Khlebnikov

Overview of this book

Security and networking are essential features of software today. The modern internet is full of worms, Trojan horses, men-in-the-middle, and other threats. This is why maintaining security is more important than ever. OpenSSL is one of the most widely used and essential open source projects on the internet for this purpose. If you are a software developer, system administrator, network security engineer, or DevOps specialist, you’ve probably stumbled upon this toolset in the past – but how do you make the most out of it? With the help of this book, you will learn the most important features of OpenSSL, and gain insight into its full potential. This book contains step-by-step explanations of essential cryptography and network security concepts, as well as practical examples illustrating the usage of those concepts. You’ll start by learning the basics, such as how to perform symmetric encryption and calculate message digests. Next, you will discover more about cryptography: MAC and HMAC, public and private keys, and digital signatures. As you progress, you will explore best practices for using X.509 certificates, public key infrastructure, and TLS connections. By the end of this book, you’ll be able to use the most popular features of OpenSSL, allowing you to implement cryptography and TLS in your applications and network infrastructure.
Table of Contents (20 chapters)
Part 1: Introduction
Part 2: Symmetric Cryptography
Part 3: Asymmetric Cryptography and Certificates
Part 4: TLS Connections and Secure Communication
Part 5: Running a Mini-CA

Message Digests

In this chapter, we will learn about message digests, also known as cryptographic hashes. Message digests, which are produced by cryptographic hash functions, have many important applications, such as data integrity checking, password verification, digital signatures, secure network protocols such as TLS, and even blockchains. We will provide an overview of the cryptographic hash functions supported by OpenSSL and recommendations on which hash functions to use and which to avoid. Then, in the practical part of this chapter, we will learn how to calculate a message digest using the command line and C code. After reading this chapter and trying the practical part, you will know why message digests are needed and how to calculate them.

We are going to cover the following topics in this chapter:

  • What are message digests and cryptographic hash functions?
  • Why are message digests needed?
  • Assessing the security of cryptographic hash functions
  • Overview...