NKRYPT is a set of eight steel pillars bearing encrypted inscriptions, located in Canberra Australia. Here are a few photographs of this artwork, along with some basic information.

Harry Houdini (1874-1926), illusionist and pioneer of the skeptics movement, had an interest in ciphers. Can you solve two encrypted telegrams he mentioned in one of his essays?

The Crypto Books page operated by Nils Kopal and Tobias Schrödel is the leading information source for books about historical cryptology. Currently, it has 541 entries.

A museum director from Switzerland is asking for help. Can a reader decipher the inscription on an executioner’s sword?

A German news magazine has published an encrypted message from a German 1970s terrorist. The solution is known, but some of the details remain unclear.

Crypto collector Ralph Simpson is compiling a list of all Kryha machines that are known to exist. Can my readers support him?

A German egyptologist claims to have deciphered the Voynich Manuscript. Does this solution make more sense than the dozens that have been published before.

In 1648, English king Charles I wrote four encrypted letters while in captivity on the Isle of Wight. Can a reader break these cryptograms?

Here’s a French letter from the 17th century, encrypted probably in a homophonic system or a nomenclator. Can a reader decipher it?

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.