CD-55 by Crypto AG

The CD-55 'LUX' was a handoperated, mechanical crypto machine containing rotors and was the first of its type produced by Crypto AG between 1955 and 1956.

The CD55 and CD-57 devices look identical from the exterior but the difference is very simple - it lies with  the keying mechanism.
The CD-55 works in the same way as the C-38, M-209 and C-446, and features simple stepping (so that could be broken easily by the NSA at the time). The CD-57 has a much more advance keying mechanism, based on the same principle as the C-52 and CX-52 (which was VERY difficult to break).

Development of both machines was started in 1955 and was completed in 1957. Both machines appeared on the marked in 1957. The differences were never explained to potential customers. NATO and NATO-friendly countries were allowed to buy the CD-57. Other countries (in particular the Arab countries) were only offered the CD-55. One of the most prominent customers of the CD-55 machine was the Vatican.

CD-55 photo courtesy John Alexander, G7GCK
Credits and References:

1) Paul Reuvers <paul(at)>

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Oct 14/16