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 to compile and link with OpenSSL

How to compile and link your program with OpenSSL depends on how you installed OpenSSL. If you are on Unix, you could install OpenSSL C headers and library files into the include and lib system directories, such as /usr/include and /usr/lib/x86_64-linux-gnu. In such a case, compilation and linking can be accomplished using one simple command:

$ cc init.c -lssl -lcrypto

The headers and library files will be looked up in the include and lib system directories. Therefore, it’s not necessary to explicitly specify directories for header and library searches. The output executable will be called a.out.

If are on Unix and the preceding command did not work for you, check that you installed the OpenSSL development package, such as libssl-dev or openssl-devel.

If you have not installed OpenSSL system-wide or do not want to use system-wide installation, you will have to specify paths to the OpenSSL C headers and library files explicitly...