Codebreaking: A Practical GuideIf you liked Dan Brown’s Da Vinci Code—or want to solve similarly baffling cyphers yourself—this is the book for you! A thrilling exploration of history’s most vexing codes and ciphers that uses hands-on exercises to teach you the most popular historical encryption schemes and techniques for breaking them. Solve history’s most hidden secrets alongside expert codebreakers Elonka Dunin and Klaus Schmeh, as they guide you through the world of encrypted texts. With a focus on cracking real-world document encryptions—including some crime-based coded mysteries that remain unsolved—you’ll be introduced to the free computer software that professional cryptographers use, helping you build your skills with state-of-the art tools. You’ll also be inspired by thrilling success stories, like how the first three parts of Kryptos were broken. Each chapter introduces you to a specific cryptanalysis technique, and presents factual examples of text encrypted using that scheme—from modern postcards to 19-century newspaper ads, war-time telegrams, notes smuggled into prisons, and even entire books written in code. Along the way, you’ll work on NSA-developed challenges, detect and break a Caesar cipher, crack an encrypted journal from the movie The Prestige, and much more. You’ll learn:
Codebreaking is the most up-to-date resource on cryptanalysis published since World War II—essential for modern forensic codebreakers, and designed to help amateurs unlock some of history’s greatest mysteries. |
Contents
| 3 | |
| 10 | |
| 17 | |
| 18 | |
Simple substitution ciphers | 29 |
How simple substitution ciphers work | 31 |
How to break a simple substitution cipher | 38 |
Success stories | 41 |
Turning grille transposition ciphers | 219 |
How to detect a turning grille encryption | 223 |
Challenges | 239 |
Digraph substitution | 243 |
How the Playfair cipher works | 245 |
How to break a digraph substitution | 252 |
Success stories | 267 |
Abbreviation ciphers | 273 |
Simple substitution ciphers without spaces between words Patristocrats | 51 |
Challenges | 60 |
Simple substitution ciphers in nonEnglish languages | 65 |
Detecting the language used | 67 |
Challenges | 78 |
Unsolved cryptograms | 80 |
Homophonic ciphers | 85 |
How homophonic ciphers work | 88 |
Success stories | 95 |
Challenges | 105 |
Codes and nomenclators | 113 |
Codes | 115 |
Superencryption of codes and nomenclators | 123 |
Challenges | 142 |
Polyalphabetic ciphers | 147 |
How a polyalphabetic cipher works | 148 |
Success stories | 161 |
Challenges | 173 |
Complete columnar transposition ciphers | 175 |
How to detect a complete columnar transposition cipher | 179 |
Success stories | 188 |
Incomplete columnar transposition ciphers | 197 |
Success stories | 206 |
Challenges | 216 |
How abbreviation ciphers work | 274 |
Challenges | 281 |
Dictionary codes and book ciphers | 285 |
How to detect a dictionary code or book cipher | 289 |
Challenges | 299 |
Additional encryption methods | 303 |
Voice encryption | 305 |
Cipher machines | 322 |
16 | 328 |
Solving ciphers with hill climbing | 329 |
Solving a homophonic cipher with simulated annealing | 340 |
Solving a turning grille cipher with hill climbing | 349 |
Solving machine ciphers with hill climbing | 358 |
What next? | 361 |
Codebreaking tools | 371 |
Journals and newsletters | 377 |
Kryptos | 379 |
Useful language statistics | 389 |
Glossary | 395 |
MORSE CODE | 403 |
References | 417 |
| 447 | |
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Common terms and phrases
abbreviation cipher algorithms alphabet American Cryptogram Association appears book cipher break British Caesar cipher challenge Chapter Chart created Cipherbrain blog ciphertext cleartext codebook codebreaking codegroups codes and nomenclators columnar transposition columns complete columnar transposition consists contains created by authors Cryptanalysis crypto cryptography Cryptologia Cryptologic CrypTool decipher decrypt diary dictionary code digraph digraph substitution Elonka Dunin encode encrypted encrypted message Encrypted postcard encryption method encryption system English text Enigma Figure fitness function following plaintext frequency analysis frequent letter German guess Here’s hill climbing homophonic cipher index of coincidence Jim Gillogly keyword length Klaus Schmeh Langie letter frequencies letter pairs look mystery plaintext plaintext candidate Playfair cipher Playfair cryptogram published Sanborn Secret sender sent simple substitution cipher solution solved steganography substitution table Success stories symbols technique telegram Thouless tion transposition cipher trigraph unsolved cryptograms Vigenčre cipher Voynich manuscript word World written Zodiac Killer


