Cryptologic History

"On This Date in Cryptologic History" Calendar

1926: Enigma introduced into German Navy as Radio Key C.

Monday, February 9, 2026

9 February 1926: Enigma was introduced into the German Navy as Radio Key C or Radio Cipher C. Learn more about the updated Enigma exhibit via the link at the bottom of this page.

Excerpt from Wikipedia:

The Reichsmarine was the first military branch to adopt Enigma. This version, named Funkschlüssel C ("Radio cipher C"), had been put into production by 1925 and was introduced into service in 1926.

The keyboard and lampboard contained 29 letters—A-Z, Ä, Ö and Ü—which were arranged alphabetically, as opposed to the QWERTZU ordering. The rotors had 28 contacts, with the letter X wired to bypass the rotors unencrypted.

Three rotors were chosen from a set of five and the reflector could be inserted in one of four different positions, denoted α, β, γ and δ. The machine was revised slightly in July 1933.

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