Editing Cryptanalysis of the Enigma (section)

==British efforts==
In 1927, the UK openly purchased a commercial Enigma. Its operation was analysed and reported. Although a leading British cryptographer, [[Dilly Knox]] (a veteran of [[World War I]] and the cryptanalytical activities of the Royal Navy's [[Room 40]]), worked on decipherment he had only the messages he generated himself to practice with. After Germany supplied modified commercial machines to the [[Spanish Civil War#Nationalists|Nationalist]] side in the [[Spanish Civil War]], and with the [[Regia Marina|Italian Navy]] (who were also aiding the Nationalists) using a version of the commercial Enigma that did not have a plugboard, Britain could intercept the radio broadcast messages. In April 1937<ref>[[Andrew Hodges|Hodges]] (1983) p. 176</ref> Knox made his first decryption of an Enigma encryption using a technique that he called ''buttoning up'' to discover the rotor wirings<ref name=CarterButtoningUp>{{citation |last=Carter |first=Frank |title=Buttoning Up: A method for recovering the wiring of the rotors used in a non-stecker Enigma |year=2004 |url=http://www.bletchleypark.org.uk/content/buttoningup.pdf |access-date=20 January 2009}}</ref> and another that he called ''rodding'' to solve messages.<ref name=CarterRodding>{{citation |last=Carter |first=Frank |title=Rodding |year=2004 |url=http://www.bletchleypark.org.uk/content/rodding.pdf |access-date=20 January 2009 |url-status=dead |archive-url=https://web.archive.org/web/20070411064026/http://www.bletchleypark.org.uk/content/rodding.pdf |archive-date=11 April 2007}}</ref> This relied heavily on [[crib (cryptanalysis)|cribs]] and on a crossword-solver's expertise in Italian, as it yielded a limited number of spaced-out letters at a time.

Britain had no ability to read the messages broadcast by Germany, which used the military Enigma machine.<ref>{{citation |title=The Spanish link in cracking the Enigma code |last=Gordon Corera |work=BBC News |date=23 March 2012 |url=https://www.bbc.co.uk/news/magazine-17486464}}</ref>