Chapter 1: Protecting Data in Motion or at Rest

We live in an exciting yet challenging time. Every second of the day there are zettabytes of data traveling over networks and the internet. Data is constantly being sent and received from our homes, cars, businesses, and billions of Internet of Things (IoT) devices. In this chapter, you'll gain an appreciation for the need to secure our data in a dynamic digital world. We'll begin with a brief look at how, over the past few decades, we have seen advances in technology that have resulted in more of our data being exchanged. Concurrent to the advances in technology, we have seen an increase in the type and amount of threats to our data.

So that you understand the many resources available on guidelines for ensuring our data is not compromised, we'll take a look at the Security architecture for Open Systems Interconnection for CCITT applications, also known as X.800. You'll learn how encryption provides many security services, which include ensuring confidentiality, integrity, authentication, forward secrecy, non-repudiation, and enhanced privacy guarantees. In addition, we'll outline some common cryptographic concepts, such as Trusted Third Party (TTP) and the Public Key Infrastructure (PKI). We'll also cover how we use the story of Bob, Alice, and other personalities to help us understand complex technical concepts.

We'll then cover some basic encryption techniques. You'll see how using substitution or transposition can scramble data into an unreadable form that won't make sense unless you have the key to decrypt the message. In order to better understand substitution and transposition, we will discuss some illustrative examples that employ two basic ciphers, namely pigpen and rail fence. Finally, we'll outline some basic techniques, such as letter frequency analysis, which can be used to break some codes.

This chapter covers the following main topics:

• Outlining the current threat landscape
• Understanding security services
• Introducing common cryptographic concepts
• Outlining substitution and transposition