Every e-mail message, every online purchase, and every cell phone call gets encrypted at one end of its journey and decrytped at the other. Now an everyday application, "crypto" is part of the job description for network designers, corporate security officers, and telecom developers. Here is a painless way to learn the basic concepts of cryptography for application in communications.While most books on the subject are full of math theory and complex algorithms, this book is not a text and has nothing to memorize--it teaches by doing as readers work through 35 modules supported by exercises and answers. * Provides a short, focused, fun experience for readers * Teaches best practice in cryptography * Proven technique--used successfully by engineering students and short-course instructors for over six years

Part I: INTRODUCTION TO SYMMETRIC CRYPTOGRAPHY
Module 1 First Considerations Exercise 1
Module 2 Plaintext Exercise 2
Module 3 Digitization of Plaintext Exercise 3
Module 4 Toward a Cryptographic Paradigm Exercise 4
Module 5 What We Want from the Keytext Exercise 5
Module 6 Randomness I Exercise 6
Module 7 Finite State Sequential Machines Exercise 7 Transition Matrix
Module 8 m-sequences Exercise 8
Module 9 The Paradigm Attempted Exercise 9
Module 10 The Block Cipher Function - A Modern Keystoneto the Paradigm Exercise 10
Module 11 Confidentiality Modes: ECB and CTR Exercise 11
Module 12 Confidentiality Mode: Output Feedback (OFB) Exercise 12
Module 13 Confidentiality Modes: Cipher Feedback (CFB)and Cipher Block Chaining (CBC) Exercise 13

Part II NUMBER THEORY WE WILL NEED
Module 14 Prime Numbers I Exercise 14
Module 15 Congruences Exercise 15
Module 16 Euler-Fermat Theorem Exercise 16
Module 17 The Euler Phi (f) Function Exercise 17
Module 18 The Binary Exponentiation Algorithm Exercise 18
Module 19 The Extended Euclidean Algorithm Exercise 19
Module 20 Primitive Roots Exercise 20
Module 21 Chinese Remainder Theorem Exercise 21

Part III INTRODUCTION TO PUBLIC KEY CRYPTOGRAPHY
Module 22 Merkle's Puzzle Exercise 22
Module 23 The Diffie-Hellman Public Key Cryptographic System Exercise 23
Module 24 Split Search Exercise 24
Module 25 A Variant of the Diffie-Hellman System Exercise 25
Module 26 The RSA Public Key Cryptographic System Exercise 26
Module 27 Prime Numbers II Exercise 27 Part IV KEYING VARIABLES
Module 28 Keying Variable Distribution Exercise 28
Module 29 Secret Sharing Exercise 29
Module 30 Randomness II Exercise 30
Module 31 Cryptovariables Exercise 31

Part V CRYPTO-OBSOLESCENCE
Module 32 The Aging Cryptoalgorithm Exercise 32
Module 33 SUPERDES(tm) Exercise 33

Part VI CHANNEL-BASED CRYPTOGRAPHY
Module 34 The Channel Is the Cryptovariable Exercise 34
Module 35 The Quantum Cryptographic Channel Exercise 35

Answers to Exercises
Glossary
Index