Introduction - Contemporary Cryptography - page 1

Chapter 1

Introduction

In this chapter, we introduce the topic of the topic (i.e., contemporary cryptography)
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 topic in Section 1.4.

1.1 CRYPTOLOGY

The term cryptology is derived from the Greek words “kryptos,” standing for
“hidden,” and “logos,” 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 topic, 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 of
messages).
More specifically, cryptology refers to the mathematical science and field of
study that comprises both cryptography and cryptanalysis.

• The term cryptography is derived from the Greek words “kryptos” (see above)

and “graphein,” standing for “write.” Consequently, the meaning of the term
cryptography is best paraphrased as “hidden writing.” According to Request
for Comments (RFC) 2828 [1], cryptography refers to the “mathematical sci-
ence that deals with transforming data to render its meaning unintelligible