Introduction to Cryptography with Open-Source Software

Contents

Preface xv

1 Introduction to cryptography 1

1.1 Hiding information: Confidentiality . . . . . . . . . . . . . . 1

1.2 Some basic definitions . . . . . . . . . . . . . . . . . . . . . 3

1.3 Attacks on a cr yptosystem . . . . . . . . . . . . . . . . . . . 5

1.4 Some crypto graphic problems . . . . . . . . . . . . . . . . . 7

1.5 Cryptographic protoc ols . . . . . . . . . . . . . . . . . . . . 8

1.6 Some simple ciphers . . . . . . . . . . . . . . . . . . . . . . 12

1.7 Cryptography and c omputer secur ity . . . . . . . . . . . . . 18

1.8 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2 Basic number theory 23

2.1 Introductio n . . . . . . . . . . .