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

Running a Mini-CA

In Chapter 8, X.509 Certificates and PKI, we learned about Public Key Infrastructure (PKI) based on X.509 certificates. In this chapter, we will learn how to use the openssl ca subcommand to run a mini-Certificate Authority (CA) that can issue certificates for internal usage in an organization. A mini-CA can be useful in organizations for establishing internal PKI, gaining control of internally used certificates, and saving costs on ordering certificates from commercial CAs. The usage of a mini-CA will be illustrated by command-line examples.

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

  • Understanding the openssl ca subcommand
  • Generating a root CA certificate
  • Generating an intermediate CA certificate
  • Generating a certificate for a web server
  • Generating a certificate for a web and email client
  • Revoking certificates and generating CRLs
  • Providing certificate revocation status via OCSP