A hundred years ago, German textile engineer Rudolf Zschweigert invented a remarkable encryption machine. A paper I recently published gives an introduction to this device.
For ten years, adventurers and puzzle fans have been hunting for a treasure hidden by US millionaire Forrest Fenn. As it seems, a person who wants to stay anonymous has now found it.
Gravestones bearing an encrypted or hidden message are one of my favorite blog topics. Here’s a speciment I recently discovered on Reddit.
A 1911 book about forensic science depicts a cryptogram. Can a reader solve it?
Postcard enthusiast Günther Hunger from Oschatz has provided me a scan of an encrypted message from the early 20th century. Can a reader decipher it?
About 110 years ago, a Mariechen Schäfer living in Frankfurt, Germany received an encrypted postcard. Can a reader solve it?
In WW2, later US president John F. Kennedy and his crew disappeared after their torpedo boat had sunk. Can my readers help to make sense of an encrypted message that was sent a few days later?
In the 1950s, a US company published weekly newspaper advertisements that included crypto puzzles. Here are three of these.
Two months ago, US book author A.J. Jacobs showed me the encrypted journal of psychologist Abraham Maslow (1908-1970). My readers did a good job in analyzing this cryptogram. Now, A.J. asks for additional help.
In 1943, the British intecepted an encrypted radio message sent from an airplane. Can a reader decipher it?