How to tell your loved one where you are, if you are a soldier and not allowed to mention your whereabouts in your letters? A German soldier in the Second World War came up with a steganographic technique.

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 animal rights organisation PETA has found interesting ways to protest against animal cruelty.

In the Cold War, US scientist Gus Simmons discovered a serious weakness in a cryptologic disarmament technology. His discovery initiated a new branch of IT security. Nevertheless, nobody seems to know how this weakness worked. The paper Simmons published about it doesn’t contain a detailed description. Does a reader know more?

Many color laser printers add tiny yellow dots to each page they print. These dots encode the printer serial number and additional information. A recently published research paper reveals new information about this secret code.

In the intro of the German TV film “Im Namens meines Sohnes” a message is hidden. It is easy to solve.

US artist Andy Bauch hid messages in his Lego artworks. Blog reader Christian Baumann has now solved two of the codes.

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.

William and Elizebeth Friedman, two of history’s greatest codebreakers, published a book dubunking the idea of hidden codes in the works of Shakespeare. However, the book itself contains a code. Can you find it?

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?