Klaus Schmeh

Klaus Schmeh ist Experte für historische Verschlüsselungstechnik. Seine Bücher "Nicht zu knacken" (über die zehn größten ungelösten Verschlüsselungsrätsel) und "Codeknacker gegen Codemacher" (über die Geschichte der Verschlüsselungstechnik) sind Standardwerke. In "Klausis Krypto Kolumne" schreibt er über sein Lieblingsthema.

In WW2, Berlin-based company Heimsoeth & Rinke not only produced the Enigma, but also a cipher cylinder, about which as good as nothing is known. Can my readers help to research the history of this device?

In 1875, a man living in Vienna received an encrypted postcard from a family member. Can you break this cryptogram?

British comedian Chris Sievey, also known as Frank Sidebottom, left behind a number of encrypted messages. British Codebreakers deciphered them and will publish the solutions in a few days. Can a reader break these cryptograms beforehand?

In the 19th century, a sailor working on the Great Lakes kept an encrypted diary. Can a reader decipher it?

In a Kansas library an unknown person has written an encrypted message into a book. Can a reader solve this “book cipher”, which is probably not a book cipher?

In 1909, an unmarried woman in Santa Monica received a postcard encrypted in an unusual cipher. Can a reader break this encryption?

My readers have shown that a Playfair cryptogram consisting of only 40 letters can be broken. Here’s a Playfair challenge with only 30 letters. Can you break it, too?

In 1978, a Kansas TV station placed a subliminal message in a TV program in order to catch a serial killer.

German poet and translator Stefan George (1868-1933) created his own secret language. It has never been deciphered – probably because only two lines written in it have survived.

A Reddit user has posted a strange cryptogram engraved on a metal plate. Can a reader make sense of it?