From the Archives: A Lady Codebreaker Speaks: Joan Murray, the Bombes and the Perils of Writing Crypto-History From Participants' Accounts

Abstract

A declassified 1970s article by Joan Murray, the World War II–Cold War British codebreaker who worked on the German naval Enigma problem, and who was engaged to Alan Turing, gives some new insights into the battle against the U-boat Enigma. As important, in the light of documents released by the British and the American since the 1990s, the article shows the ganders in using a participant's memories as final evidence. Although privy to the secrets of Bletchley Park, Murray was, for example, unaware of the near equal power of England's own four-wheel Bombes compared to those designed in America.

Keywords:

• Agnes Driscoll
• Alan Turing
• Bombe
• Enigma
• Joan Clarke
• Joan Murray
• Joseph Wenger

Acknowledgements

The author wishes to thank Ralph Erskine for his advice, information, and patience while waiting for this item to be submitted for publication.

Notes

¹There are convincing indications that this FOIA release was from (23) Ralph Erskine gives that citation in (11, p. 219). He seems to have received a somewhat different response to an FOIA request for the same document.

²Insight into the scope of the literature may be found in (4, 6, and 26. A similar open publication by Murray, “Hut Eight and Naval Enigma, Part I”, is in: (13, pp. 113–118).

³The early monumental work on the subject is (14).

⁴For the authoritative obituary for Clarke, see (7). For a longer biography that mentions the engagement ring, see (10).

⁵Ralph Erskine alerted this author to the British Bombe descriptions in (29) and to the three diagonal board machines.

⁶An excellent article on the subject is (31).

⁷Ralph Erskine has found that in October 1943 only some 3.5 of the 18 Keen four-wheel Bombes were in full operation. Communication with Erskine, February 2009.

⁸These assertions are found in, (16–18).

⁹See (2) and his presentation at the NSA Historical Symposium, 2005.

¹⁰For a general overview, see (20) On what was exchanged, see (8 and 9).

¹¹On the American Navy's view, see (17).

¹²Communications with Ralph Erskine, January 2008 and (27).

¹³(22) is an invaluable resource that awaits even deeper analysis.

¹⁴(5, pp. 25–520) contains a easily readable treatment of Driscoll's views and actions.

¹⁵The critical document on Driscoll is (28), but on alternative attacks see (12 and 19).

¹⁶Ralph Erskine pointed out these errors of memory in correspondence with this author.

¹⁷Although the numbers are buried in the detailed documents, (21 and 25) reveal the specifics of retained machines.

¹⁸On the United States’ continued use, see (3), On the British targets, see (1, 15, and 30).