Here are episodes 15 to 17 of my comic strip “Chief Security Officer”.

Once again, the secret of the world’s most mysterious manuscript has been unlocked. This time the alleged solution comes from Russia. Does this one make more sense than the many others published before?

For centuries nomenclators were the most popular kind of encryption. Still today messages enciphered with a well-designed nomenclator are hard or even impossible to break.

British parapsychologist Robert Thouless published a cryptogram and tried to transmitt the key after his death. I have started a similar experiment – based on modern cryptography.

Crypto expert Elonka Dunin has discovered a steganographic message on the tombstone of William and Elizebeth Friedman.

British psychologist and parapsychologist Robert Thouless (1894-1984) published a short cryptogram. He intended to channel the key after his decease from the realm of the dead. So far, this experiment has failed. Thouless’ cryptogram is still unsolved.

My recent article about Brazilian student Bruno Borges, who has mysteriously vanished and has left behind encrypted notes, has attracted much attention. Most of Borges’ notes seem to be deciphered. However, there is at least one passage that still waits to be solved.

In the end credits of the movie Fair Game (2010) some letters are marked yellow. Do they form a code? If so, the solution is unknown.

In 1948 an encrypted telegram was sent  from New York to Tel Aviv, Israel. Can a reader break this encryption?

An 18th century monument in Shugborough Hall near Birmingham, UK, bears an inscription consisting of ten letters. This message is one of the world’s most famous unsolved ciphertexts.