Siemens and Halske T52

The Siemens & Halske T52, also called " secret Telegraph ", in World War II was a German encryption machine for radio teletype. She received by British and American cryptologists the code name " Sturgeon " ( German: "Fault ") within the stream cipher system cipher - FISH. From the T52 600-1200 machines were produced from 1932.

While the Enigma was used by mobile troops in general, the T52 came to command units of the Air Force for use. Originally developed for the German Navy, the Air Force began a heavy and bulky secretary from 1942 and operating it stationary. Similarly role of Lorenz key accessory SZ40/42 was (the other subsystem of FISH) used in the army.

While you had to read in the result of the Enigma encryption, write and then send these steps in the T52 performed automatically. The operator had the text so only enter, then this is automatically encrypted and sent. When receiving the decryption and printing was also automated. One of the advantages of this simplification was that the operator of two connected devices with the key text did not come into contact. It was 5 independent binary pseudo-random number generators that have been linked exclusive - or with 5-bit Baudot code, first at the transmitter, then the receiver.

In contrast to Enigma the rolls of the T52 were not wired. The rolls had several non-modifiable pins that closed an electrical circuit depending on the position or not.

The machine gained some importance in the history of cryptography, it has been deciphered for various reasons only partially. The code of the T52 was independent of Arne Beurling, and scientists at Bletchley Park deciphered ( code-named Sturgeon FISH there for T52, FISH Tunny for Lorenz SZ42 ). There were incompatible with each other variants T52a, T52b, T52c, T52ca and T52d. The variants a and b were cryptologically weak. T52d contrast, was a decisive improved apparatus that no longer had the recognized crass errors of predecessors, such as a small hand crank to reset the key unit, which meant that many crypto messages were sent with the same key. A significant weakening of cryptography learned the system by repeated inappropriate operation, even with regard to key selection and other reductions in the anticipated key space.