Lorenz used the International Teleprinter Code, in which each letter of the alphabet was represented by a series of five electrical impulses. Extra letters were generated by the rotors and added to the original text. Five of the twelve rotors followed a regular pattern and two pinwheels dictated the pattern of the other five. To decrypt a message, the receiving Lorenz added the same obscuring letters.


  • Title: Teleprinter Tape
  • Date: 1939/1945
  • Location: Bletchley Park
  • Rights: Crown Copyright. By kind permission Director GCHQ

Get the app

Explore museums and play with Art Transfer, Pocket Galleries, Art Selfie, and more


Google apps