In 1934, an inmate of the Ohio State Penitentiary tried to hand an encrypted message to a visiting woman. A warden intercepted the message, a codebreaker in Washington could decipher it. Can a reader figure out what kind of cipher was used?


Around 1920, a US pulp magazine published an encrypted message exchange in its “missed persons” column. The cleartexts might refer to a familiy drama. Even two of the world’s greatest codebreakers apparently could not make sense of these cryptograms.


In 1863, during the US Civil War, a Union soldier wrote a letter to an unknown recipient. This letter is encoded in a shorthand, probably Pitman. Can a reader decipher it?


In 1948, an anonymous codebreaker deciphered an encrypted message by British parapsychologist Robert Thouless. The solution is known. Can a reader find out how the successful attack worked?


Today’s crypto mystery is about a postcard written to a noblewoman in 1914. Can a reader solve it?


The US Navy cryptologists use a logo that contains an encrypted message. Can a reader decipher it?


Eight words and a question mark. That’s the content of an old encrypted postcard from New York City. Can a reader decipher it?


The main library of the Vatican owns an encrypted letter from 1628. Can a reader break this cryptogram?


A postcard from 1885 was written in a strange code. Can a reader decipher it?


US outsider artist James Hampton (1909-1964) created only one notable piece of art. In addition, he left behind over 100 pages of encrypted notes that are unsolved to date.