Codebreaking

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.

Preface
Chapter 1: How can I break an encrypted message? And other introductory questions
Chapter 2: The Caesar cipher
Chapter 3: Simple substitution ciphers
Chapter 4: Simple substitution ciphers without spaces between words: Patristocrats
Chapter 5: Simple substitution ciphers in non-English languages
Chapter 6: Homophonic ciphers
Chapter 7: Codes and nomenclators
Chapter 8: Polyalphabetic ciphers
Chapter 9: Complete columnar transposition ciphers
Chapter 10: Incomplete columnar transposition ciphers
Chapter 11: Turning grille transposition ciphers
Chapter 12: Digraph substitution
Chapter 13: Abbreviation ciphers
Chapter 14: Dictionary codes and book ciphers
Chapter 15: Additional encryption methods
Chapter 16: Solving ciphers with hill climbing
Chapter 17: What next?
Appendix A: Kryptos
Appendix B: Useful language statistics
Appendix C: Glossary
Appendix D: Morse Code
Appendix E: Figure Sources
References