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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 merely 5 1/8in × 3 1/8in × 1 1/2in (13 × 8 × 3.8 cm) and weighed 1.5 pounds (680 gr). The CD-57 used six wheels.
Sullivan (2002) shows how the CD-57 can be attacked using a hill climbing search technique.
- one website gives the production dates as "1956 and 1957" , another website says "first produced in 1957" https://web.archive.org/web/20060317161354/http://www.gemmary.com/instcat/11/p25-214-11.html. Archived from the original on March 17, 2006. Retrieved December 9, 2005. Missing or empty
-  Archived December 29, 2004, at the Wayback Machine
- Wayne G. Baker, Solving a Hagelin, Type CD-57, Cipher, Cryptologia, 2(1), January 1978, pp1–8.
- Louis Kruh, Cipher Equipment: Hagelin Pocket Cryptographer, Type CD-57, Cryptologia, Volume 1, 1977, pp255–260.
- Geoff Sullivan, Cryptanalysis of Hagelin machine pin wheels, Cryptologia, 26(4), pp257–273, October 2002.
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