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

Establishing TLS Connections and Sending Data over Them

In this chapter, we will learn about the Transport Layer Security (TLS) protocol. The TLS protocol is the successor of the Secure Sockets Layer (SSL) protocol and is used for secure network communication and serves as the basis for higher-level protocols, such as Hypertext Transfer Protocol Secure (HTTPS) and Simple Mail Transfer Protocol Secure (SMTPS). The TLS protocol is most visible on the World Wide Web but is also used in other applications, such as file transfer, email, instant messaging, Voice over IP, remote access, connection to databases, financial data transmission, and many other applications that require encrypted communication.

We will learn about the basics of the TLS protocol and take a quick look at its history. In the practical part of this chapter, we will learn how to establish TLS connections, send data over them, and shut them down correctly. There will be both command-line and C code examples that illustrate...