Pinwheel (cryptography)

Pinwheels might be turned through a purely mechanical action (as in the M-209) or electromechanically (as in the Lorenz SZ 40/42).

The Swedish engineer Boris Caesar Wilhelm Hagelin[1] is credited with having invented the first pinwheel device in 1925.

The device was later introduced in France and Hagelin was awarded the French order of merit, Legion d'Honneur, for his work.

[3] One of the earliest cipher machines that Hagaelin developed was the C-38 and was later improved into the more portable Hagelin m-209.

Pinwheels can be viewed as a predecessor to the electronic linear-feedback shift register (LFSR), used in later cryptosystems.