The Basics of Information Security, 2nd Edition

Chapter 5

Cryptography

In this chapter, we discuss the use of cryptography. We go over the history of such tools, from very simple substitution ciphers to the fairly complex electromechanical machines that were used just before the invention of the first modern computing systems, and how they form the basis for many of our modern algorithms. We cover the three main categories of cryptographic algorithms: symmetric key cryptography, also known as private key cryptography; asymmetric key cryptography; and hash functions. We also talk about digital signatures that can be used to ensure that data has not been altered, and certificates that allow us to link a public key to a particular identity. In addition, we cover the mechanisms we use to protect ...