Manual transposition cipher 'Rasterschlüssel 44'

Rasterschlüssel 44, RS44, a manual transposition cipher, introduced by the German Armed Forces in March 1944

German manual cipher the Allies could not break quickly, 1944.

This cipher, known as Rasterschlüssel 44, was very difficult and time-consuming for Allied code-breakers to break. Introduced in 1944, this German grid-based system was an effective combination of security and relative ease of use.

The original message was written down in select rows and encrypted by taking characters from select columns to create the encrypted message.

The rows and columns selected were defined by the message 'key'. To decrypt the message this process was reversed.