3 Symmetric Cryptography

In this chapter, you will be introduced to the concepts, theory, and practical aspects of symmetric cryptography. More focus will be given to the elements that are specifically relevant in the context of blockchain technology. This chapter will provide the concepts 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, the OpenSSL command-line tool is used. Before starting with the theoretical foundations, the installation of OpenSSL is presented in the following section so that you can do some practical work as you read through the conceptual material.