In this chapter, you will be introduced to the concepts, theory, and practical aspects of symmetric cryptography. We will focus more on the elements that are specifically relevant in the context of blockchain technology. We will provide you with concepts that are required to understand the material covered in later chapters.
You will also be introduced to applications of cryptographic algorithms so that you can gain hands-on experience in the practical implementation of cryptographic functions. For this, we'll use the OpenSSL command-line tool. Before starting with the theoretical foundations, we'll look at the installation of OpenSSL in the following section, so that you can do some practical work as you read through the conceptual material.
