Agony-Bible-bar

Two years ago, I blogged about five encrypted 19th century newspaper ads that contain Bible references. Blog reader Thomas Ernst found an interesting solution approach, but so far nobody has deciphered these cryptograms.

Wien-RKA-K1-bar

Peter Nüchterlein, the writer-in-residence in Wernigerode, Germany, has asked me for help. In a Vienna archive he has found over 100 encrypted documents from the Thirty Years’ War. Today, I am going to introduce five of them. Can a reader decipher them?

Pigpen-Graffiti-bar

Can you decipher this encrypted graffiti that was found near Rome, Italy? The encryption method used looks like a Pigpen variant.

Cards-bar

Designing a secure manual encryption algorithm is a challenge. Some cryptographers have developed ciphers that require a deck of playing cards. The best-known one of this kind is Bruce Schneier’s Solitaire. Today, I am going to introduce another one: Talon by Aaron Toponce.

Gillogly-Challenge-bar

20 years ago, Jim Gillogly, a great codebreaker and reader of this blog, created three crypto challenges – a Playfair, a Double Playfair, and a Double Column Transposition. Can you solve them?

Nomenclator-Post-bar

Three months ago, I presented a terminology for codes and nomenclators, based on a workshop that took place at the HistoCrypt conference. After having received some interesting feedback, I can now provide an update.

Aldino-bar

A message written 118 years ago in Aldino, Maryland, waits to be solved. Can you break this cryptogram?

Vernam-Challenge-bar

The Vernam cipher is mentioned in dozens of cryptography books. It is simple and more secure than most other basic encryption methods. Can you solve the three Vernam challenges I am going to introduce today?

New-York-Poster-bar

An advertisment poster an Instagram user has seen in a New York subway is completely encrypted. Can you decipher it? And can you tell me what is behind the “spiritual consultancy” that has published this poster and a few others?

Simmons-Covert-bar

In the Cold War, US scientist Gus Simmons discovered a serious weakness in a cryptologic disarmament technology. His discovery initiated a new branch of IT security. Nevertheless, nobody seems to know how this weakness worked. The paper Simmons published about it doesn’t contain a detailed description. Does a reader know more?