A PhD student has come across an encrypted message written by a 19th century anarchist. Can a reader break this encryption?

A fourth encrypted bottle post has been found in the river Alster in Hamburg. Still nobody seems to have a clue what these strange messages mean.

Here are ten criminals who used encryption – including the notorious Unabomber.

Here are episodes 21 to 25 of my comic strip “Chief Security Officer”.

Ernest Rinzi was a 19th century jeweler, goldsmith and miniaturist. He left behind an encrypted journal that is still unsolved. My first impression is that this journal is the most notable unsolved encrypted book after the Voynich Manuscript and the Rohonc Codex.

The Freemasons are known to have created a great variety of encrypted documents. Can a reader solve this one from the 19th century?

Five years ago an encrypted carrier pigeon message from World War II hit the news. So far, nobody has been able to decipher it.

An encrypted postcard from the 1870s is written in a strange code. Can a reader solve it?

In October 1984 unemployed German food engineer Günther Stoll died of murder or accident. Shortly before his death he had written the word YOG’TZE on a piece of paper. Neither the reason of Stoll’s death nor the meaning of YOG’TZE has ever been found out.

A 17th-century Italian nun claimed that the Devil had dictated an encrypted letter to her. Scientists have now allegedly broken this cryptogram. Details are not known yet.