cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adver ...

, a pinwheel was a device for producing a short

pseudorandom A pseudorandom sequence of numbers is one that appears to be statistically random, despite having been produced by a completely deterministic Determinism is a philosophical view, where all events are determined completely by previously exi ...

sequence of

bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...

s (determined by the machine's initial settings), as a component in a cipher machine. A pinwheel consisted of a rotating wheel with a certain number of positions on its periphery. Each position had a "pin", "

cam Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bind ...

" or "lug" which could be either "set" or "unset". As the wheel rotated, each of these pins would in turn affect other parts of the machine, producing a series of "on" or "off" pulses which would repeat after one full rotation of the wheel. If the machine contained more than one wheel, usually their periods would be

relatively prime In mathematics, two integers and are coprime, relatively prime or mutually prime if the only positive integer that is a divisor of both of them is 1. Consequently, any prime number that divides does not divide , and vice versa. This is equivale ...

to maximize the combined period. Pinwheels might be turned through a purely mechanical action (as in the

M-209 In cryptography, the M-209, designated CSP-1500 by the United States Navy (C-38 by the manufacturer) is a portable, mechanical cipher machine used by the US military primarily in World War II, though it remained in active use through the Korean W ...

) or

electromechanical In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...

ly (as in the

Lorenz SZ 40/42 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'' was derived from ''Schlüssel-Zusatz'', meaning ''ciph ...

Development

The Swedish engineer Boris Caesar Wilhelm Hagelin is credited with having invented the first pinwheel device in 1925. He developed the machine while employed by

Emanuel Nobel Emanuel Ludvig Nobel ( , ; Saint Petersburg, 1859 – Stockholm, 31 May 1932) was a Swedish oil baron, the eldest son of Ludvig Nobel and his first wife, Mina Ahlsell, grandson of Immanuel Nobel and nephew of Alfred Nobel. Businessman After ...

to oversee the Nobel interests in Aktiebolaget Cryptograph. He was the nephew of the founder of the

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

. The device was later introduced in France and Hagelin was awarded the French order of merit,

Legion d'Honneur The National Order of the Legion of Honour (french: Ordre national de la Légion d'honneur), formerly the Royal Order of the Legion of Honour ('), is the highest French order of merit, both military and civil. Established in 1802 by Napoleon B ...

, for his work. One of the earliest cipher machines that Hagaelin developed was the C-38 and was later improved into the more portable Hagelin m-209. The M-209 is composed of a set of pinwheels and a rotating cage. Other cipher machines which used pinwheels include the C-52, the

CD-57 The (Hagelin) CD-57 was a portable, mechanical cipher machine manufactured by Crypto AG, first produced in 1957. It was derived from the earlier CD-55, and was designed to be compatible with the larger C-52 machines. Compact, the CD-57 measured ...

and the

Siemens and Halske T52 The Siemens & Halske T52, also known as the Geheimschreiber ("secret teleprinter"), or ''Schlüsselfernschreibmaschine'' (SFM), was a World War II German cipher machine and teleprinter produced by the electrical engineering firm Siemens & Halske. ...

. Pinwheels can be viewed as a predecessor to the electronic

linear-feedback shift register In computing, a linear-feedback shift register (LFSR) is a shift register whose input bit is a linear function of its previous state. The most commonly used linear function of single bits is exclusive-or (XOR). Thus, an LFSR is most often a sh ...

(LFSR), used in later cryptosystems.

References

Encryption devices Cryptographic hardware {{crypto-stub

Development

See also

References