View source for C-52 (cipher machine)

{{short description|1950s cipher machines by  Crypto AG}}
[[File:Hagelin CX-52-IMG 0568-white.jpg|thumb|The CX-52]]
[[Image:BC-52.jpg|right|thumbnail|A combination of a C-52 cipher machine with a B-52 keyboard attachment, such as pictured here, was denoted the BC-52.]]
[[Image:Hell 54.jpg|thumbnail|upright|A Hell 54, a licensed German copy of the C-52]]
[[File:Hagelin CX-52.jpg|thumb|Hagelin CX-52 from the Argentine Computer Museum, exhibited at Ekoparty 2023]]

{{redirect|BC-52|the music band, the BC-52's|BC-52's}}

The '''([[Boris Hagelin|Hagelin]]) C-52''' and '''CX-52''' were cipher machines manufactured by [[Crypto AG]] starting 1951/1952. These pin-and-lug type cipher machines were advanced successors of the C-38/[[M-209]]. The machine measures {{convert|8+1/2|x|5+3/8|x|4+3/8|in|cm}}. The device is mechanical, but when combined with an electric keyboard attachment, the '''B-52''', the resultant system is termed the '''BC-52'''. The B-52 is larger, measuring {{convert|12+1/2|x|8+1/2|x|6+3/8|in|cm}}.

The '''Hell 54''' was a licensed copy of the C-52 by German company Hell.

== Structure and operation ==

Both C and CX models are equipped with six pinwheels. In the C-52 version, these six wheels are chosen from a possible set of 12, with the number of pins on each wheel  being 25, 26, 29, 31, 34, 37, 38, 41, 42, 43, 46, and 47. The C model had a fixed stepping system with a large wheel cycle due to the mutually prime factors in the pin counts. The CX-52 version has 6 pinwheels with 47 pins each and a flexible wheel movement system. The lug cage of both models contains 32 movable bars: 27 of the bars are used for encryption and the remaining 5 bars control the stepping of the pinwheels. The early CX models used the control bars also for encryption but due to complications in creating acceptable lug settings later CX models used these bars only for controlling of the wheel stepping. The stepping of the CX wheels was controlled by adjustable lugs on the control bars.

The C-52 and CX-52 were very flexible machines that could be produced in various ways, creating a unique machine with unique cryptographic characteristics for each customer. There were special detachable wheel movement bars and their position on the drum could change, interchangeable print wheels, custom pinwheel labels, versions with One-time Tape reader instead of wheels,<ref>{{cite web
|url=http://www.jproc.ca/crypto/cx52.html
|title=CX-52/C-52 by Crypto AG
|first=Mark
|last=Sims
|accessdate=2015-10-09
}}</ref> versions that only enciphered numbers, and many other details that influenced the enciphering process.

== Breaking and compromising ==
There is some speculation that the CX-52 might have been broken by the signals intelligence services of Communist [[East Germany]], [[Czechoslovakia]], and [[Polish People's Republic|Poland]].<ref>{{Cite journal|title = From the Archives: CX–52 Messages Read by Red Poles?|journal = Cryptologia|date = 2009-09-18|issn = 0161-1194|pages = 347–352|volume = 33|issue = 4|doi = 10.1080/01611190902742467|first = Jan|last = Bury|s2cid = 42774841}}</ref>

Many of the C-52 and CX-52 machines sold by Crypto AG were compromised to benefit the US and British national signals intelligence agencies, [[National Security Agency]] (NSA) and [[Government Communications Headquarters]] (GCHQ), respectively.<ref name=BBC-2015-07-28>{{cite news
|url=https://www.bbc.com/news/uk-33676028
|publisher=[[BBC]]
|title=How NSA and GCHQ spied on the Cold War world
|date=2015-07-28
|accessdate=2015-10-09
|last=Corera
|first=Gordon
|work=BBC News
}}</ref> For details, see [[Crypto AG#Compromised machines|Crypto AG § Compromised machines]].

==See also==
* [[Operation Rubicon (Crypto AG)]]
*[[M-209]]
* [[C-36 (cipher machine)]]
* [[CD-57]]

== Notes and references ==

{{Reflist}}

==External links==
{{Commons category|CX-52}}
* H. Paul Greenough, Cryptanalysis of the Hagelin C-52 and similar machines a known plaintext attack, ''Cryptologia'', 23(2), July 1999, pp139&ndash;156.
* Louis Kruh, The Hagelin Cryptographer, Type C-52, ''Cryptologia'' 3(2), April 1979, pp78&ndash;82.
* Jan Bury, [http://www.tandfonline.com/doi/abs/10.1080/01611190902742467 From the Archives: CX-52 Messages Read by Red Poles?], ''Cryptologia'' 33(4), October 2009, pp347&ndash;352.
* Jan Bury, [http://www.tandfonline.com/doi/abs/10.1080/01611194.2012.713804 Polish Cold War Codebreaking of 1959–1989: A Preliminary Assessment], ''Cryptologia'' 36(4), October 2012, pp341&ndash;379.
* [https://www.ciphermachinesandcryptology.com/en/c52tech.htm Technical details of the C-52 and CX-52] Encryption principle and machine variations, by Dirk Rijmenants
* [https://www.ciphermachinesandcryptology.com/en/bc-52.htm Dirk Rijmenants' Hagelin BC-52 Simulator]
* {{usurped|1=[https://web.archive.org/web/20021202035859/http://hem.passagen.se/tan01/cx52.html The HAGELIN cryptographer CX-52]}} by Torbjorn Andersson &mdash; a write-up, photograph and a [[QBASIC]] simulator.
* [http://www.jproc.ca/crypto/cx52.html Jerry Proc's page on the CX-52] &mdash; also covers the B-52 keyboard unit.
* Photographs: [https://web.archive.org/web/20060226123506/http://home.ca.inter.net/~hagelin/C52-1.jpg], [https://web.archive.org/web/20060226123417/http://home.ca.inter.net/~hagelin/C52-2.jpg], [https://web.archive.org/web/20050116072449/http://www.deathstar.ch/security/encryption/history/images/CX-52_01.jpg], [http://www.apprendre-en-ligne.net/crypto/instruments/cx52.jpg], [https://web.archive.org/web/20050217070503/http://www.eclipse.net/~dhamer/images/A143082_022As.JPG], [https://web.archive.org/web/20050211103205/http://www.homeworlds.com/crypto/Cipher_Machines_Pictures.html]
* [http://www.jproc.ca/crypto/hell54.html Jerry Proc's page on the Hell 54] &mdash; a licensed copy of the C-52 by Hell
* [http://www.codasaurus.com/ubb/Forum29/HTML/000040.html Descriptions from sales of C-52 and CX-52 equipment]
* [https://web.archive.org/web/20080725085317/http://www.gemmary.com/instcat/11/11-001.html CX-52 Cryptographic Machine & B-52 Motorized Base]
* [http://scz.bplaced.net/mfs_zco.html#cx52 CX-52-related Stasi files]

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[[Category:Encryption devices]]