Tissie and Jabber as well as Harry and Caroline were two amorous couples, who exchanged encrypted messages via newspaper ads more than a century ago. Their encryption codes are unsolved to date.


Last week I presented the mystery of an encrypted note found in an antique silk dress. Has the codebook used now been found?


A young man, who had disappeared from his home in California, sent an encrypted message from Israel to his parents. This cryptogram has been unsolved for over four decades. Can a reader decipher it?


A letter sent by some Oscar P. Schaub in the 1920s looks like it has been written in Hebrew or a similar script. However, even Hebrew experts can’t read it. Is it encrypted in a clever cipher?


A postcard from 1910 is encrypted in three different ciphers. Can a reader solve this unusual cryptogram?


In 2014 Maryland-based costume collector Sara Rivers-Cofield discovered an encrypted note in an antique silk dress. This cryptogram is unsolved to date.


A third encrypted bottle post has been found in the river Alster in Hamburg. Can a reader decipher these mysterious messages? Can we find out who is behind these strange bottle posts?


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.


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.