While in New York Carlsen and Karyakin are playing their final games, I am going to present three (alleged) secret codes related to chess.

Pietro Giannone (1791–1872), an Italian poet and patriot, left behind an encrypted poem filling a whole book. After nearly 150 years, mathematics teacher Paolo Bonavoglia broke the encryption.

An Italian website reports on an encrypted notebook written by a 16th century nun. The encryption is unsolved. Can a reader help to shed some more light on this crypto mystery?

Two more encrypted postcards wait to be solved. Can a reader help?

A number of encrypted postcards from different times and places wait to be solved. Can a reader help?

50 postcards written by two aerospace technicians in 1968 contain encrypted and hidden messages. If you want to solve them you should listen to “The Soyuz Files” podcast.

In World War 1 a female spy in France used a chess board and chess pieces to code a secret message.

In the 1950s the Germans used a unique crypto device named “Violine”. I have always wondered what it was used for. In a book about espionage I found the likely answer.

Researchers tested whether two artificial intelligence systems could develop an ecryption algorithm a third one could not break. In some test runs it worked.

Two texts in a book written by Renaissance genius Francis Bacon contain hidden messages. Can a reader find them?