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

The Lorenz SZ42 machine with its covers removed. Bletchley Park museum

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.

Bletchley Park

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Bletchley Park is an English country house and estate in Bletchley, Milton Keynes, that became the principal centre of Allied code-breaking during the Second World War. During World War II, the estate

Lorenz cipher

…Kent, its outstation at Higher Wincombe in Wiltshire, and at Denmark Hill in south London, and forwarded to the Government Code and Cypher School at Bletchley Park (BP). Some were deciphered using hand methods before the process was partially automated, first with Robinson machines and then with the Colossus…

The mansion in 2017

Bletchley's Polish Memorial, commemorating "the [prewar] work of Marian Rejewski, Jerzy Różycki and Henryk Zygalski, mathematicians of the Polish intelligence service, in first breaking the Enigma code. Their work greatly assisted the Bletchley Park code breakers and contributed to the Allied victory in World War II."

Stephen Kettle's 2007 Alan Turing statue

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