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)
1
Part 1: Introduction
3
Part 2: Symmetric Cryptography
8
Part 3: Asymmetric Cryptography and Certificates
12
Part 4: TLS Connections and Secure Communication
16
Part 5: Running a Mini-CA

Understanding digital signatures

A digital signature is an array of bits that provides cryptographically strong guarantees of authenticity, integrity, and non-repudiation of a digital message. What do those guarantees mean? Let’s take a look:

  • Authenticity means that the message is coming from the claimed sender, provided that only the claimed sender possesses the private key that was used to produce the signature.
  • Integrity means that the message has not been changed by a third party during transmission, for example.
  • Non-repudiation means that the sender cannot deny that they produced the signature, provided that no one else has had access to the private key that was used to produce the signature.

A digital signature is produced using a private key that can be verified using the corresponding public key. Hence, digital signature and verification algorithms are considered asymmetric cryptography algorithms, even though they are not asymmetric encryption...