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

How to generate a symmetric encryption key

Generating an encryption key for symmetric encryption is surprisingly easy. You just request the needed amount of random bytes from your cryptographically secure random generator!

Which random generator is considered cryptographically secure? It is a random generator that generates bytes that are extremely hard to predict. The unpredictability of generated random bytes is accomplished by using the entropy caused by unpredictable events from the outside world. Often, cryptographically secure random generators use the entropy caused by the unpredictable timing of the input from a keyboard and mouse. If the keyboard and mouse are unavailable, for example, when an application is running in a container, then another source of entropy can be used, such as microfluctuations in the CPU speed. Another common entropy source is a ring oscillator that can be included in the CPU or another chip.

What is the correct amount of random bytes? It is the...