My readers have shown that a Playfair cryptogram consisting of only 50 letters can be broken. Here’s a Playfair challenge with only 40 letters. Can you break it, too?

I have an appearance in a YouTube video that introduces the ten most notable unsolved cryptograms. More than a million people have already watched it.

Canadian artist Zen Rankin has published two encrypted messages he created in his youth days. Can a reader break them?

An alleged cryptanalyst has published a new hypothesis about the Somerton Man cryptogram on Wikipedia. Does it make sense?

A video by US musician Laurie Anderson contains a spoken sequence of numbers. Can a reader make sense of it?

At first sight, an encrypted postcard from 1909 looks like many others I have introduced on this blog. However, the encryption method used is unusual.

An encrypted telegram from Italy is unsolved. Can a reader find the codebook that was used? Without the codebook, deciphering the telegram is as good as impossible.

Two days ago, on Thanksgiving, the NSA sent encrypted greetings to “every NSA employee across the globe”. Can you break this encryption?

In 1913, an unknown person sent an encoded postcard to a man living in the then German town of Nieder-Jeutz. It is not possible to decipher this card unambiguously, but a few guesses can be made.

Once again, an unsolved cryptogram has been published on Reddit. No details are provided. It is not even clear what is above and what below. Can a reader solve this mystery?