## Markovian Parallax Denigrate: The Internet’s oldest and weirdest mystery

Over two decades ago, a series of strange messages were spread in the Usenet. Their origin and purpose are still a mystery.

## Revisited: Thomas Urquhart’s encrypted poems

Scottish poet Thomas Urquhart (1611-1660) left behind two unsolved cryptograms. Along with many others, they are listed on a website maintained by Eugen Antal.

## Can a reader help to correctly decrypt this WW2 message?

In 1941, a sender in Hamburg, Germany, transmitted an encrypted message to a receiver in Rio de Janeiro, Brazil. The encryption method and the key are known, but the plaintext has not been completely deciphered yet.

## Unsolved: An encrypted postcard from Switzerland

In 1931, a woman from Bonn, Germany, received an encrypted postcard from Switzerland. Can a reader break this cryptogram?

## A “Playfair for Three” challenge

The “Playfair for Three” is a manual cipher that works similar as the Playfair, but is based on trigraphs instead of digraphs. Can you solve a challenge cryptogram that has been made with this method?

## The encrypted diary of Ignaz Meyer

Ignaz Meyer, a Bavarian teacher and town writer, wrote an encrypted diary. The content of this joural gives interesting insights into the life of a 19th century individual who had a drinking problem and was not very successful in his job.

## Two anamorphic postcards from the early 19th century

An anamorphic is a puzzle based on a special kind of secret writing. Here are two postcards with anamorphic motives. Can you decrypt them?

## WW2 codebreaker Alan Turing to be the face of new British £50 note

The Bank of England has announced that Enigma cryptanalyst Alan Turing will appear on the new £50 banknote.

## Can you solve this bigram challenge and set a new world record?

Substituting letter pairs (also known as bigrams or digraphs) is an encryption method invented in the 16th century. Can you break a new challenge I have made?

## A CNN documentary about Kryptos – featuring Elonka Dunin

In March, I blogged about a TV documentary about the Kryptos sculture produced by CNN. It has now aired and is available on Youtube.