This book has been written with a broad spectrum of readers in mind, which
includes anyone interested in secrecy and related issues. Thus, this is a tome
for the merely curious, as well as history-minded readers, amateur mathematicians,
engineers, bankers, academics, students, those practitioners working in
cryptography, specialists in the field, and instructors wanting to use the book
for a text in a course on a variety of topics related to codes. We will look at
this topic from all aspects including not only those related to cryptography (the
study of methods for sending messages in secret), but also the notion of codes
as removal of noise from telephone channels, satellite signals, CDs and the like.
The uninitiated reader may consider the following. Imagine a world where
you can send a secret message to someone, and describe to anyone listening
in precise detail how you disguised the message. Yet that person could not
remove the disguise from that message no matter how much time or how many
resources are available. Well, that world exists in the here and now, and the
methodology is called public-key cryptography. It permeates our lives, from the
use of a bank card at an automated teller machine ATM to the buying of items
or bank transactions over the Internet. You can even purchase items over the
Internet and do so anonymously, as you would using hard cash. In this book,
you will find out how this is done.