Network Security: Private Communication in a Public World, Second Edition

7. Number Theory

7.1. Introduction

This chapter describes enough of number theory to understand not only the mathematical operations necessary to perform cryptographic algorithms such as RSA, but to understand why they work. The chapter requires no background other than intellectual curiosity, a vague remembrance of high school algebra, a certain amount of trust that it will all be understandable with just a little bit of thought, and a reasonable night's sleep in the recent past.

Some of this material has been covered in previous chapters with a large waving of hands. Other material in here has merely been referenced. If you're happy to take the results on faith, don't bother reading this chapter.

7.2. Modular Arithmetic

We were rather imprecise ...