If 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.
How to crack simple substitution, polyalphabetic, and transposition ciphers
How to use free online cryptanalysis software, like CrypTool 2, to aid your analysis
How to identify clues and patterns to figure out what encryption scheme is being used
How to encrypt your own emails and secret messages
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.
About the Author
Elonka Dunin is an experienced crypto expert and maintains a list of the world's most famous unsolved codes on her elonka.com website. Bestselling author Dan Brown even named one of the characters in his Da Vinci Code sequel, The Lost Symbol, after her: “Nola Kaye” is a scrambled form of “Elonka." She is co-founder and co-leader of a group of cryptographers who are working hard to crack the final cipher on the famous Kryptos sculpture at CIA Headquarters, and in 2021 she was invited to give the TEDx talk "2,000 Years of Ordinary Secrets."
Klaus Schmeh is the most-published cryptology author in the world. He has written 15 books (in German) about the subject, as well as over 200 articles, 25 scientific papers, and 1,500 blog posts. He is a member of the editorial board of the scientific magazine, Cryptologia. Schmeh's main fields of interest are codebreaking and the history of encryption. His blog Cipherbrain is read by crypto enthusiasts all over the world. Schmeh is a popular speaker, known for his entertaining presentation style involving self-drawn cartoons and LEGO® models.
“Codebreaking: A Practical Guide is quite the best book on codebreaking I have read: clear, engaging, and fun. A must for would-be recruits to GCHQ and the NSA!” —Sir Dermot Turing, author of Prof, the biography of his uncle, Alan Turing
“Riveting. Dunin and Schmeh show us that we each have our own inner code-breaker yearning to be set free. Codebreaking isn’t just for super-geniuses with supercomputers; it’s something we were all born to do.” —Mike Godwin, creator of Godwin’s law and former general counsel for the Wikimedia Foundation
“This is THE book about codebreaking. Very concise, very inclusive, and easy to read. Good references for those who would make codes, too, like Kryptos.” —Ed Scheidt, CIA
“A compendium of historical cryptography. Approachable, accessible, this book brings back the joy I felt when I first read about these things as a kid.” —Phil Zimmermann, creator of PGP encryption and inductee into the Internet Hall of Fame
“One of the most helpful guides outside the NSA to cracking ciphers. But even if you don’t become a codebreaker, this book is full of fascinating crypto lore.” —Steven Levy, New York Times best-selling author of Crypto, Hackers, and Facebook: The Inside Story
“Another kind of Applied Cryptography.” —Whitfield Diffie, Turing Laureate and creator of public-key cryptography
“This is the book of my dreams. Super-clear, super-fun guide for solving secret messages of all kinds.” —Jason Fagone, author of the best-selling book The Woman Who Smashed Codes
“Kool dnoces a htrow era snootrac eht fo ynam.” —Suomynona Ecila
“A wonderful mix of ciphers, both famous and little-known, solved and unsolved. Beginners will be hooked on exploring the world of secrets in cipher, and those who have already been introduced to the field will find much that is new.” —Craig Bauer, editor in chief of Cryptologia and author of Unsolved!: The History and Mystery of the World’s Greatest Ciphers
“Cryptography? Ciphers? I thought this would be an easy book to put down. I was very wrong.” —Steve Meretzky, co-author with Douglas Adams of The Hitchhiker’s Guide to the Galaxy computer game
"Fun, fascinating, and user friendly . . . Expertly written, organized and presented, [Codebreaking] is unreservedly recommended as a supplemental Code Breaking curriculum textbook." —Midwest Book Review