A cryptogram that was found on the wall of a tunnel at the University of Texas has been discussed on several websites for years. Can a reader of this blog finally find the solution?

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.

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?

Three years ago, US codebreaker Gary Klivans provided me a screenshot that shows a seemingly random sequence of letters created by a criminal. So far, nobody has been able to make sense of this cryptogram.