Codes, Ciphers, Steganography & Secret Messages

Discover the science of cryptology! This book is a complete introduction to codes, ciphers and secret messages. You will discover:
- How codes and ciphers work
- How secret messages can be concealed in apparently innocuous messages (steganography)
- How codebreakers and cryptanalysts break codes and ciphers
- Many examples of how codes and ciphers have changed history and continue to shape the world to this day

Table of Contents

Introduction: What are Codes, Ciphers and Steganography?

Chapter 1: Codes used for Communication
Flag Code
Semaphore Code
Polybius Square
Optical Telegraph Codes
Electrical Telegraph Codes
- International Morse Code
- Baudot Code
- Murray Code and ITA 2
- ASCII
Computer Codes

Chapter 2: Caesar Ciphers
Using a Caesar Cipher
Variations of the Caesar Cipher
- ROT13
- ROT5
- ROT18
- ROT47
- Avgad and Albam
Breaking Caesar Ciphers

Chapter 3: Simple Substitution Ciphers
Atbash Cipher
Simple Alphabet Substitution Ciphers
Simple Symbolic Substitution Ciphers
- Pigpen Cipher
Breaking Simple Substitution Ciphers
- Frequency Analysis
- Cribs
Defeating Frequency Analysis
- Short Messages
- Homophony
- Null Characters
- Other Methods

Chapter 4: Transposition Ciphers
Scytale
Rail Fence Ciphers
Route Ciphers
Columnar Transposition Ciphers
Double Columnar Transposition Ciphers
Myszkowski Transposition Ciphers
Disrupted Transposition Ciphers
Grille Ciphers
- Trellis Ciphers
- Fleissner Ciphers
- Crossword Ciphers

Chapter 5: Fractionation and Diffusion
Bifid Cipher
Trifid Cipher

Chapter 6: Polygraphic Substitution
Advantages and Disadvantages of Polygraphic Ciphers
Playfair Cipher
Two-Square Cipher
Four-Square Cipher

Chapter 7: Polyalphabetic Ciphers
Alberti Cipher
Trithemius Cipher
Vigenиre Ciphers
Beaufort and Variant Beaufort Cipher
Autokey Ciphers

Chapter 8: Enigma
The Enigma Machine
How Enigma was Broken
- Early British Efforts
- Polish Cipher Bureau
- Polish Cooperation with the Western Allies
- PC Bruno
- Cadix
- British Efforts Against Italian Naval Enigma
- The British Focus on Cribs
- British and American Bombes
- German Suspicions

Chapter 9: Perfect Ciphers
Vernam Cipher
One-Time Pads
Difficulties of Implementing a Perfect Cipher
- Protecting the Key
- Not Reusing the Key
- Randomness in the Key
- The Equipment Used Must Be Secure
Lorenz Cipher
- Cryptanalysis of the Lorenz Cipher

Chapter 10: Codewords
One-time Code
Nomenclator
Midway

Chapter 11: Book Ciphers
Book Word Substitution Ciphers
Book Letter Substitution Ciphers
Running Key Ciphers

Chapter 12: Computer Cryptography
Symmetric-Key Cryptography
Public-Key Cryptography
Cryptographic Hashes and Digital Signatures

Chapter 13: Steganography and Hidden Messages
Null Ciphers
Bacon’s Cipher
Grilles
Digital Steganography
- Image Files
- Audio Files
- Text and Word Processor Files
- Network Communications
- Other Examples

Chapter 14: Famous Codes, Ciphers and Cryptograms – Solved and Unsolved
Voynich Manuscript
Babington Plot Ciphers
Olivier Levasseur
Shugborough Inscription
Copiale Cipher
The Gold Bug
Beale Ciphers
Rohonc Codex
D'Agapeyeff Cipher
Dorabella Cipher
Zimmerman Telegram
Zodiac Killer Ciphers
Kryptos
The Magic Words are Squeamish Ossifrage
Ricky McCormick's Encrypted Notes
Smithy Code

Conclusion