**CLASSICAL CRYPTOLOGY**

Ancient Roots

Caveman Crypto

Greek Cryptography

Viking Cryptography

Early Steganography

**Monalphabetic Substitution Ciphers, or MASCs: Disguises for Messages**

Caesar Cipher

Other MASC Systems

Edgar Allen Poe

Arthur Conan Doyle

Frequency Analysis

Biblical Cryptology

More Frequencies and Pattern Words

Vowel Recognition Algorithms

More MASCs

Cryptanalysis of a MASC

Unsolved Ciphers by a Killer and a Composer

Affine Ciphers

Morse Code and Huffman Coding

MASC Miscellanea

Nomenclators

Cryptanalysis of Nomenclators

Book Codes

**Simple Progression to an Unbreakable Cipher**

Vigenère Cipher

History of the Vigenère Cipher

Cryptanalysis of the Vigenère Cipher

Kryptos

Autokeys

Running Key Cipher and Its Cryptoanalysis

One-Time Pad or Vernam Cipher

Breaking the Unbreakable

Faking Randomness

Unsolved Cipher from 1915

OTPs and the SOE

History Rewritten!

**Transposition Ciphers**

Simple Rearrangements and Columnar Transposition

Cryptanalysis of Columnar Transposition

Historic Uses

Anagrams

Double Transposition

Word Transposition

Transposition Devices

**Shakespeare, Jefferson, and JFK**

Shakespeare vs. Bacon

Thomas Jefferson: President, Cryptographer

Cipher Wheel Cryptanalysis

Playfair Cipher

Playfair Cryptanalysis

**World War I and Herbert O. Yardley**

Zimmermann Telegram

ADFGX: A New Kind of Cipher

Cryptanalysis of ADFGX

Herbert O. Yardley

Peacetime Victory and a Tell-All Book

Case of the Seized Manuscript

Cashing in, Again

Herbert O. Yardley: Traitor

Censorship

**Matrix Encryption**

Levine and Hill

How Matrix Encryption Works

Levine’s Attacks

Bauer and Millward’s Attack

More Stories Left to Tell

**World War II: The Enigma of Germany**

Rise of the Machines

How Enigma Works

Calculating the Keyspace

Cryptanalysis Part 1. Recovering the Rotor Wirings

Cryptanalysis Part 2. Recovering the Daily Keys

After the Break

Alan Turing and Bletchley Park

Lorenz Cipher and Colossus

What If Enigma Had Never Been Broken?

Endings and New Beginnings

**Cryptologic War against Japan**

Forewarning of Pearl Harbor?

Friedman’s Team Assembles

Cryptanalysis of Red, a Japanese Diplomatic Cipher

Purple: How It Works

Purple Cryptanalysis

Practical Magic

Code Talkers

Code Talkers in Hollywood

Use of Languages as Oral Codes

**MODERN CRYPTOLOGY**

Claude Shannon

About Claude Shannon

Entropy

One More Time

Unicity Points

Dazed and Confused

**National Security Agency**

Origins of NSA

TEMPEST

Size and Budget

The *Liberty *and the *Pueblo*

Church Committee Investigations

Post Cold War Downsizing

Some Speculation

2000 and Beyond

Interviewing with NSA

BRUSA, UKUSA, and Echelon

**Data Encryption Standard**

How DES Works

Reactions to and Cryptanalysis of DES

EFF vs. DES

Second Chance

Interesting Feature

Modes of Encryption

**Birth of Public Key Cryptography**

Revolutionary Cryptologist

Diffie-Hellman Key Exchange

RSA: Solution from MIT

Government Control of Cryptologic Research

RSA Patented, Alice and Bob Born Free

**Attacking RSA**

Eleven Non-Factoring Attacks

Factoring Challenge

Trial Division and the Sieve of Eratosthenes (ca. 284–204 BCE)

Fermat’s Factorization Method

Euler’s Factorization Method

Pollard’s *p *– 1 Algorithm

Dixon’s Algorithm

Pollard’s Number Field Sieve

**Primality Testing and Complexity Theory**

Some Facts about Primes

Fermat Test (1640)

Miller-Rabin Test

Deterministic Tests for Primality

Complexity Classes, **P **vs. **NP**, Probabilistic vs. Deterministic

Ralph Merkle’s Public Key Systems

Knapsack Encryption

ElGamal Encryption

**Authenticity**

Problem from World War II

Digital Signatures (and Some Attacks)

Hash Functions: Speeding Things Up

Digital Signature Algorithm

**Pretty Good Privacy**

Best of Both Worlds

Birth of PGP

In Zimmermann’s Own Words

Impact of PGP

Implementation Issues

**Stream Ciphers**

Congruential Generators

Linear Feedback Shift Registers

LFSR Attack

The Cellphone Stream Cipher A5/1

RC4

**Suite B All-Stars**

Elliptic Curve Cryptography (ECC)

Personalities behind ECC

Advanced Encryption Standard (AES)

AES Attacks

**Possible Futures**

Quantum Cryptography: How It Works

Quantum Cryptography: Historical Background

DNA Computing

**Index**