Heute geht es um fünf verschlüsselte Botschaften, die zwar lösbar aussehen, aber bisher allen Dechiffrier-Versuchen widerstanden haben.

A challenge cryptogram from a 2012 puzzle book is still unsolved. The author will award a book copy to the first one who breaks it.

Sometimes, deciphering a cryptogram is easier than reading the deciphered message. Here are two plaintexts I have difficulties to understand.

A hidden message has been found on a paved square in Steyr, Austria. Now, the creator of this steganogram has to cover the costs for removing it.

The gravestone of William and Elizebeth Friedman in Washington, DC, bears a hidden message. A few days ago I had the chance to go on site and take a look at it. Here’s my report, including a video that shows Elonka Dunin explaining the code.

Cardsharping with steganography is a popular motive on classical paintings. Here are five examples.

In July 1918 a British officer, who was imprisoned in Turkey, sent a letter to a girl in London. This letter contains a hidden message. Can somebody help me to find out what kind of code was used?

Blog reader Martin Lohner has created a piece of music that hides a message. Can you find it?

Fascinating stories about hidden messages in texts, pictures and other objects – this is what my new book “Versteckte Botschaften” is about. Here are some of the highlights of this work.

Acrostics are a data hiding technique that has been in use for centuries. The latest example is contained in a letter of resignation written by a US committee last week.