Contemporary Cryptography pdf

Contemporary Cryptography Wonderful Digest

Chapter 1

Introduction

In this chapter, we introducethe topic of the book (i.e., contemporarycryptography) at a high level of abstraction. More specifically, we elaborate on cryptology(includ-ing cryptography)in Section 1.1, address cryptographic systems (or cryptosystems) in Section 1.2, provide some historical background information in Section 1.3, and outline the rest of the book in Section 1.4.

1.1 CRYPTOLOGY

The term cryptology is derived from the Greek words “kryptós,” standing for “hidden,” and “lógos,” standing for “word.” Consequently, the meaning of the term cryptology is best paraphrased as “hidden word.” This paraphrase refers to the original intent of cryptology, namely to hide the meaning of specific words and to protect their confidentiality and secrecy accordingly. As will (hopefully) become clear throughout the rest of the book, this viewpoint is far too narrow, and the term cryptology is nowadays used for many other security-related purposes and applications (in addition to the protection of the confidentiality and secrecy ofmessages).

More specifically, cryptology refers to the mathematical science and field of study that comprises both cryptographyand cryptanalysis.