Breaking 19th Century Encrypted Newspaper Ads With Modern Means

Presented at A New HOPE (2022), July 23, 2022, noon (50 minutes)

In the 19th century, encrypted newspaper advertisements were a common method of communication. They were used to transmit everything from love messages and business information to family news. Publication in a newspaper ensured that a message could be received anonymously and virtually everywhere, even by people on the go. Encryption ensured that (at least in theory) only the intended recipient could read the note. The three presenters of this talk have collected hundreds of encrypted newspaper ads from the 19th century from England, France, and the United States. Some of these ads are unique while others form series of messages, the longest of which includes over 50 advertisements published over several years. Some messages were solved quickly, some are still being solved today, and others remain unsolved.

To solve ciphertexts of this kind, modern codebreaking tools can be used, such as the open-source software CrypTool 2 or the free online service dCode.

This talk presents the most interesting newspaper ads from the lecturers' collection along with the background stories. It is shown how these messages can be broken with modern algorithms implemented in free software tools. In addition, some of the toughest unsolved advertisements are introduced and potential solution approaches are explained.


Presenters:

  • Elonka Dunin
    **Elonka Dunin (@ElonkaDunin) (elonka.com)** is an experienced crypto expert, 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. She maintains a list of the world’s most famous unsolved codes on her elonka.com site, and has written multiple books, including *The Mammoth Book of Secret Codes and Cryptograms*. Bestselling author Dan Brown named one of the characters in his *Da Vinci Code* sequel, *The Lost Symbol*, after her. (“Nola Kaye” is an anagrammed form of “Elonka.”) She is a member of the board of directors for the National Cryptologic Foundation, and is a lifetime member of the International Game Developers Association. With co-author Klaus Schmeh, she recently published the book *Codebreaking: A Practical Guide*, as well as an article in the academic journal *Cryptologia* on hill climbing techniques, entitled, “How We Set New World Records in Breaking Playfair Ciphertexts.” In 2021, she gave the TEDx talk, “2,000 Years of Ordinary Secrets.”
  • Klaus Schmeh
    **Klaus Schmeh (@KlausSchmeh) (schmeh.org)** is the most-published cryptology author in the world. He has written 15 books (in German) about the subject, as well as over 250 articles, 25 scientific papers, and 1500 blog posts. Klaus’s main fields of interest are codebreaking and the history of encryption. His blog *Cipherbrain* is read by crypto enthusiasts all over the world. Klaus is a popular speaker, known for his entertaining presentation style involving self-drawn cartoons and Lego models. He has lectured at hundreds of conferences, including the NSA Cryptologic History Symposium, HistoCrypt, the Charlotte International Cryptologic Symposium, and the RSA Conference in San Francisco. In his day job, Klaus works for an IT security company. With co-author Elonka Dunin, he recently published the book *Codebreaking: A Practical Guide*, as well as an article in the academic journal *Cryptologia* on hill climbing techniques, entitled, “How We Set New World Records in Breaking Playfair Ciphertexts.”
  • A.J. Jacobs
    **A.J. Jacobs (@ajJacobs) (ajjacobs.com)** is an author, journalist, lecturer, and human guinea pig. He has written four *New York Times* bestsellers that combine memoir, science, humor, and a dash of self-help. He is also editor at large at *Esquire Magazine*, a commentator on NPR, and a columnist for *Mental Floss Magazine*. He has appeared on *Oprah*, *The Today Show*, *Good Morning America*, CNN, *The Dr. Oz Show*, *Conan,* and *The Colbert Report*. He has given several TED talks, including ones about living biblically, creating a one-world family, and living healthily. For his latest book, *The Puzzler: One Man’s Quest to Solve the Most Baffling Puzzles Ever, From Crosswords to Jigsaws to the Meaning of Life*, A.J. dived into the world of puzzles, including cryptography and codebreaking.

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