he Turning Grille is a historical method of cryptography, invented by Eduard Fleißner von Wostrowitz in 1881. It was used in 1916 by the Germans in WW1.

This toolset is intended to help people understand the technique of this special form of cipher by visualizing the grille and giving an easy tool to encrypt and decrypt own messages. By that the user can learn a lot about cryptography in general and especially the methods of transposition ciphers.

In addition it mediates the amount of security given by this cipher by a simple brute-force analysis.


The cipher is presented as an educational example of historical cryptography. Do not use the tool to encrypt your correspondence as it is not a strong cipher.

This tool has been developed by Matthias Schneider within a seminar about IT security headed by Bernhard Esslinger at the University of Siegen, Germany.