Today I’m going to report about an unsolved encrypted document created five centuries ago and now owned by the Beinecke Library in Connecticut. And no, I’m not talking about the Voynich manuscript.


The Beale cryptograms are the greatest hoax in crypto history. Generations of treasure hunters have tried to solve them and to find the hidden treasure, the location of which they allegedly describe. Nobody has ever been successfull, as the treasure simply does not exist.


A new Tengri 137 challenge has shown up. Blog reader Norbert Biermann found the solution – codebreaking at its best. Now the next Tengri 137 puzzle is waiting to be solved.


The M-209 is a small and robust encryption machine used by the US Army in World War II. Although several cryptologists have developed powerful methods to break the M-209, one series of messages is still unsolved.


In 1906 an unknown person sent an encrypted postcard from St. Petersburg, Russia, to Vaasa, Finland. Can a reader decrypt it?


US citizen David Rayburn killed his wife, his step-son, and himself. Years later, an encrypted text allegedly written by him emerged. This cryptogram is unsolved to this day.


Two years ago a detectorist found an encrypted note hidden in a WW2 bullet in central Italy. Despite many tries this cryptogram is still unsolved.


During World War II a woman from Loiret, France, sent an encrypted message to a recipient in Nantes, France. Can a reader break this cryptogram?


The longest key ever publicly broken by exhaustive key search has 64 bits. A challenge I created a few years ago aims to improve this world record by one bit.


ADFGVX is an encryption method used by the Germans in WW1. Some 20 ADFGVX radio messages from 1918 are still unsolved.