On completing this chapter, you will be able to
Present a brief history of cryptography
Describe the difference between symmetric and asymmetric algorithms
Explain how DES, 3DES, and AES work
Describe how hashing algorithms are built
Compare SSL and TLS
This chapter covers some basic building blocks you need to understand before moving on to more complex security technologies. All secure communication these days relies on cryptography. After a brief history of cryptography, the chapter presents a closer look at some modern-day techniques such as 3DES, AES, and RSA. There is also a brief discussion about hashing, and the chapter concludes by explaining the use of certificates and the different certification authorities (CAs) that are in use today.
Before dipping into the history of cryptography, you need to consider a question: What is cryptography? Cryptography is the science of writing or reading coded messages. It is one of the oldest recorded fields of technical study. Cryptography is the basic building block on which security principles such as authentication, integrity, and confidentiality are built.