Fish (cryptography)
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Fish was the UK's Government Code and Cypher School Bletchley Park codename for any of several German teleprinter stream ciphers used during World War II. Enciphered teleprinter traffic was used betwe
German prisoners prepare the "Russian Fish" for loading and shipment to England.
The Lorenz SZ42 machine with its covers removed. Bletchley Park museum
Lorenz cipher
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The Lorenz SZ40, SZ42a and SZ42b were German rotor stream cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. The model name SZ is derived from
Fish (cryptography)
…of enciphered transmission between central headquarters and headquarters in the field. The transmissions were known as Fish at Bletchley Park. (See Lorenz cipher, Cryptanalysis of the Lorenz cipher.) The German army used Fish for communications between the highest authorities in Berlin and the high-ranking…
The Lorenz SZ machines had 12 wheels each with a different number of cams (or "pins"). OKW/Chi wheel name ABCDEFGHIKLM BP wheel name ψ1 ψ2 ψ3 ψ4 ψ5 μ37 μ61 χ1 χ2 χ3 χ4 χ5 Number of cams (pins) 434751535937614131292623
Cams on wheels 9 and 10 showing their raised (active) and lowered (inactive) positions. An active cam reversed the value of a bit (0→1 and 1→0).
A rebuilt British Tunny at The National Museum of Computing, Bletchley Park. It emulated the functions of the Lorenz SZ40/42, producing printed cleartext from ciphertext input.