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

Digital Signatures and Their Verification

In this chapter, we will learn about digital signatures and how to sign content and verify the signature later. Digital signatures have many important practical applications, such as signing documents, certificates, software, and network requests and responses, including financial transactions. Digital signatures are also important for the security of cryptocurrencies, such as Bitcoin and others. Digital signature algorithms are a necessary building block for client and server identity verification in secure network protocols, such as TLS, SSH, and IPsec. Digital signatures are used both in the TLS protocol handshake and for signing X.509 certificates, which are used for identity presentation and verification in TLS. More information about X.509 certificates will be provided in Chapter 8, X.509 Certificates and PKI. The TLS protocol will be covered in Part 4, TLS Connections and Secure Communication. Digital signatures are also used in secure...