ABSTRACT
This chapter presents an overview of some basic ideas underlying encryption technology. The chapter
begins by defining some basic terms and follows with a few historical notes so the reader can appreciate
the long tradition that encryption, or secret writing, has had. The chapter then moves into modern
cryptography and presents some of the underlying mathematical and technological concepts behind
private and public key encryption systems such as DES and RSA. We will provide an extensive discussion
of conventional private key encryption prior to introducing the concept of public key cryptography. We
do this for both historical reasons (private key did come first) and technical reasons (public key can be
considered a partial solution to the key management problem).
