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 are X.509 certificates issued?

The X.509 certificate generation procedure consists of several stages:

  1. The applicant (future certificate owner) generates the certificate’s private and public keys.
  2. The applicant generates a Certificate Signing Request (CSR). The CSR contains the subject, the public key of the future certificate, the X509v3 extensions requested by the applicant, and the CSR signature. The CSR is signed by the certificate’s private key.
  3. The applicant sends the CSR to a CA for signing.
  4. The CA checks the applicant’s identity.
  5. The CA makes a certificate based on information from the CSR. The CA also adds other information to the certificate, such as the issuer, validity fields, and X509v3 extensions. Finally, the CA signs the certificate.
  6. The CA sends the certificate back to the applicant, who then becomes the certificate owner or holder.

Note that no one exposes the private key to another party in the process.