Page 4 ‘A technical history’: J. K. Batey, M. L. Batey, M. Rock and P. F. G. Twinn, ‘A History of the Solution of Unsteckered Enigmas and Abwehr Machine Cyphers 1941–1945’ (catalogued as ‘GC&CS Secret Service Sigint Volume II: Cryptographic Systems and their Solution. I Machine Cyphers’: TNA PRO HW 43/7).
Page 5 ‘Amateur cryptanalysts can now solve ‘: Geoff Sullivan and Frode Weierud have solved more than seventy authentic German army Enigma daily keys, without the benefit of cribs (probable plain text used as the basis for ‘menus’ for the bombes – fast key-finding aids): see Geoff Sullivan and Frode Weierud, ‘Breaking German Army Ciphers’, Cryptologia (2005), vol. 29, pp. 193–232; also at http://www.tandf.co.uk/journals/pdf/papers/ucry_06.pdf (accessed 1 July 2009). GC&CS seldom, if ever, achieved that, and found German army Enigma signals even more difficult to solve than Kriegsmarine Enigma messages.
The M4 Message Breaking Project has broken two genuine Kriegsmarine messages enciphered on four-rotor Enigma (out of three intercepts available), again without cribs: http://www.bytereef.org/m4_project.html (accessed 1 July 2009).
Page 6 ‘Not an isolated example’: There are many examples, especially in the TNA PRO HW 43 series. Thus GCHQ continues to withhold files HW 43/33 and 34 on ‘The Japanese Fleet General Purpose System’ (JN 25) although the US Navy, which broke far more JN 25 systems than GC&CS, has released a full account of its codebreaking methods in ‘Techniques and Procedures used in the Cryptanalysis of JN-25 by Station Negat’: NACP, RG 38, Radio Intelligence Publications, RIP 171. The decision to withhold HW 43/33 and 34 is redolent of GCHQ’s earlier decision to withhold all the Room 40 files.
GCHQ even continues to classify some German secrets from the Second World War, such as Ticom I-38 (report on interrogation of Lt. Frowein of OKM/4 SKL/III, on his work on the security of the German naval four-wheel Enigma) – see the withholding card in TNA PRO HW 40/176. Frowein merely recounts how he solved messages enciphered on the four-rotor Kriegsmarine Enigma, using punched cards. To claim that information on such methods endangers British security almost sixty-five years later beggars belief. The report is available elsewhere, yet there is not the slightest indication that national security has suffered as a result.
Such ridiculous classification decisions virtually destroy any confidence one might otherwise have in GCHQ’s judgment about the classification of wartime documents.
Page 7 ‘Paradoxically, the American’: http://www.gpo.gov/congress/commissions/secrecy/pdf/03sum.pdf, p.xxi (accessed 1 July 2009).
Page 8 ‘The US Homeland Security’: Homeland Security Advisory Council, ‘Top Ten Challenges Facing the Next Secretary of Homeland Security’, http://www.fas.org/irp/agency/dhs/topten.pdf (accessed 1 July 2009).
A deputy under-secretary of defence, counter-intelligence and security told a Congressional sub-committee in 2004 that 50 per cent of the United States government’s defence secrets might be overclassified: see Too Many Secrets: Overclassification as a Barrier to Critical Information Sharing, US Government Printing Office, 2005, testimony of Carol A. Haave, p. 82, (http://bulk.resource. org/gpo.gov/hearings/108h/98291.pdf, accessed 1 July 2009); William Leonard, the director of the Information Security Oversight Office, put the figure as ‘over 50 percent’: ibid., p. 83.
Page 9 ‘Dilly specialised’: On the A to C machines, see Dr Siegfried Türkel, Chiffrieren mit Geraten und Maschinen, Verlag Ulr. Mosers Buchhandlung (J. Meyerhoff), Graz, 1927, pp. 71–94; Cipher A. Deavours and Louis Kruh, Machine Cryptography and Modern Cryptanalysis, Artech House, Dedham, MA, 1986, pp. 94–6.
Page 10 ‘The main Abwehr Enigma’: The Germans called it the ‘counter’ (Zählwerk) Enigma because it had a counter for the number of letters enciphered; it was sometimes described by the Allies as a ‘Group II’ machine.
Page 11 ‘Most regrettably’: F. H. Hinsley and C. A. G. Simkins, British Intelligence in the Second World War, vol. IV: Security and Counter-intelligence, HMSO, London, 1990, p. 108. On Sicherheitsdienst (SD, the intelligence service of the Nazi Party) Enigma, see ibid., p.182, fn. In 1943, the main Abwehr (‘counter’) Enigma was employed between Berlin, Madrid, Lisbon, Paris, Bordeaux and the Italian and Balkan cities: GISK 1 in ‘Descriptions of German Cipher Types GISOS, GIMP, GISK and GISKXY’ (NARA HCC, Box 606, Nr. 1587). For details of the Abwehr Enigma machines and their characteristics, see ‘Descriptions of German Cipher Types GISOS, GIMP, GISK and GISKXY’; ‘Tentative List of Enigma and other Machine Usages’ (HCC, Box 580, Nr. 1417).
Page 12 ‘25 December 1941’: TNA PRO HW 19/85.
Page 13 ‘Rejewski mathematical methods’: Marian Rejewski, ‘How the Polish Mathematicians Broke Enigma’, in Władysław Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, tr. Christopher Kasparek, University Publications of America, MD, 1984, p. 246.
Page 14 ‘Inspired guess’: Ralph Erskine, ‘The Poles Reveal their Secrets: Alastair Denniston’s Account of the July 1939 Meeting at Pyry’, Cryptologia (2006), vol. 30, p.300.
Page 15 ‘Cape Verde Operation’: See Ralph Erskine and Frode Weierud, ‘Naval Enigma: M4 and its Rotors’, Cryptologia (1987), vol. 11, p. 235.
Page 16 ‘Dilly showed remarkable’: If Dilly’s recommendation had been implemented earlier, Hut 8 (naval Enigma) would probably not have had to confess to ‘an episode in the history of the section over which even the least sensitive of us would gladly draw a veil of considerable opacity’. It had failed to recognise that Porpoise (Süd), an Enigma key used in the Mediterranean, was employing an outmoded indicating system. If it had known about the system in time, it ‘could certainly have been reading it for some months, possibly since 1941’. Hut 6 did know, but no arrangements had been made to inform Hut 8: see C. H. O’D. Alexander, ‘Cryptographic History of Work on the German Naval Enigma’ (PRO HW 25/1), p. 38; Ralph Erskine, ‘Naval Enigma: An Astonishing Blunder’, Intelligence and National Security (1988), vol. 3, no. 1, p. 162.
Page 17 ‘Burials of essential documents’: Knox, undated note about a meeting on 19 March 1942 with ‘the Brigadier’ (Brigadier Stewart Menzies – ‘C’), TNA PRO HW 25/12.
Page 18 ‘Over sixty years later’:The 9/11 Commission Report, Final Report of the National Commission on Terrorist Attacks upon the United States, p. 417: http://www.9-11commission.gov (accessed 1 July 2009).
Page 19 ‘Dilly ensured’: Knox to Denniston, letter, 7 January 1940: TNA PRO HW 14/3.
Page 20 ‘Learned crucial information’: ‘The History of Hut 6, vol. I’, p.53: PRO HW 43/70; F. H. Hinsley and others, British Intelligence in the Second World War, vol. III, part 2, HMSO, London, 1984, p. 952.
Page 21 ‘After he returned’: ‘The History of Hut 6, vol. I’, p.55.
Page 22 ‘A method, “cillies”’: On cillies, see Ralph Erskine, ‘Cillies’, in Ralph Erskine and Michael Smith (eds), Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, Bantam, London, 2001, p. 453.
Page 23 ‘Provided excellent “cribs”’: ‘Notes on the History of ISOS’: TNA PRO HW 19/316. The ISOS section was ‘entirely dependent upon busts and cribs from ISK’ for solving traffic on some of the main Abwehr networks for several months in 1944: ibid., para. 21.
Page 24 Magisterial official history’: F. H. Hinsley and others, British Intelligence in the Second World War: Its Influence on Strategy and Operations, three volumes in four parts, HMSO, London, 1979, 1981, 1984 & 1990.
Page 25 ‘To be of value’: On the importance of ISK and ISOS, see Hinsley and Simkins, British Intelligence in the Second World War, vol. IV, p. 281.
Page 26 ‘Constantly had to struggle’: See further, E. D. R. Harrison, ‘British Radio Security and Intelligence, 1939-43’: The English Historical Review (2009), vol. CXXIV, no. 506, pp. 53–93; Hinsley and Simkins, British Intelligence in the Second World War, vol. IV, p. 132.
Page 27 ‘Kim Philby’: See Anthony Cave Brown, Treason in the Blood: H. St. John Philby
, Kim Philby, and the Spy Case of the Century, Robert Hale, London, 1995, p. 330; cf. Desmond Bristow, with Bill Bristow, A Game of Moles: The Deceptions of an MI6 Officer, Warner, London, 1993, pp. 33, 264.
Page 28 ‘Pas de Calais and Belgium’: See Michael Smith, ‘Bletchley Park, Double Cross and D-Day’, in Erskine and Smith (eds), Action This Day, p. 299.
Chapter 1: The making of a codebreaker
Page 1 ‘A profitable talk in the summerhouse’: Penelope Fitzgerald, The Knox Brothers, Coward, McCann & Geoghegan, New York, 1977, p. 26.
Page 2 ‘Like Herrick’: Edmund Arbuthnott Knox, Reminiscences of an Octogenarian 1847–1934, Hutchinson, London, 1934.
Page 3 ‘In August 1892 she died’: see Fitzgerald, Knox Brothers, p. 37.
Page 4 ‘A death grapple’: see ‘Mothering famous people’, Daily Chronicle, 12 May 1930.
Page 5 ‘Mrs K and the girls picking up the balls’: see Evelyn Waugh, The Life of the Right Reverend Ronald Knox, Chapman & Hall, London, 1959, p. 67.
Page 6 ‘Ronnie used Baconian reasoning’: see Ronald Clark, The Man Who Broke Purple: The Life of The World’s Greatest Cryptologist, Colonel William F. Friedman, Weidenfeld & Nicolson, London, 1977, p. 219.
Page 7 ‘I was not unprepared for difficulties’: Knox, Reminiscences of an Octogenarian.
Page 8 ‘A most loathsomely untidy, unintelligible, illegible condition’: Fitzgerald, Knox Brothers, pp. 66–7.
Page 9 ‘You must forgive me’: ibid., pp. 71, 91–2.
Page 10 ‘Loved by all’: ibid., pp. 78–9; ‘University Intelligence’, The Times, 12 February 1907.
Page 11 ‘Too austere and uncongenial’: ibid., p. 119.
Page 12 ‘His argument was so clever that nobody could contradict it’: ibid., p. 94.
Chapter 2: Room 40
Page 1 ‘This sort of Nelsonian exercise had to be abandoned’: see Robin Denniston, Thirty Secret Years: A.G. Denniston’s Work in Signals Intelligence 1914–1944, Polperro Heritage Press, Clifton-upon-Teme, 2007, p. 34.
Page 2 ‘Arms rigid in death’: Winston S. Churchill, The World Crisis, vol. I: 1911–1914, Thornton Butterworth, London, 1923, p. 251.
Page 3 ‘Communication with merchantmen’: see Patrick Beesly, Room 40: British Naval Intelligence 1914–18, Hamish Hamilton, London, 1982, pp. 3–4.
Page 4 ‘Begin codebreaking in real earnest’: ibid., p. 7.
Page 5 ‘Three additional copies’: see Denniston, Thirty Secret Years, p. 34.
Page 6 ‘The wish that Ewing would “associated himself continuously” with this work’: Christopher Andrew, Secret Service: The Making of the British Intelligence Community, Heinemann, London, 1985, p. 90.
Page 7 ‘Although the bombarded towns…’: Churchill, The World Crisis, p. 264.
Page 8 ‘There can be few purely mental experiences…’: ibid., p. 335.
Page 9 ‘The Log became an object of hatred…’: Denniston, Thirty Secret Years, p. 35.
Page 10 ‘One of our torpedo boats will be running out’: Andrew, Secret Service, p. 92.
Page 11 ‘An excellent choice’: TNA PRO HW 3/3 ‘Narrative of Captain Hope’, Appendix to History of Room 40 OB.
Page 12 ‘In preparation for the war’: see Mavis Batey, From Bletchley with Love, Bletchley Park Trust, Milton Keynes, 2008, p. 3; Godfrey memoirs cf p44.
Page 13 ‘Working in the censorship department’: David Kahn, The Codebreakers: The Story of Secret Writing, Scribner, New York, 1996, p. 285.
Page 14 ‘Earlier in this account…’: Churchill, The World Crisis, p. 606.
Page 15 ‘These signal books…’: ibid., p. 607.
Page 16 ‘The telegram was first sorted to Knox…’: TNA PRO HW 3/177.
Page 17 ‘I’ve got a telegram’: see David Ramsay, ‘Blinker’ Hall, Spymaster: The Man Who Brought America into World War I, History Press, Stroud, 2008, Chapter XI for account of the Zimmermann telegram from Hall’s unpublished autobiography.
Page 18 ‘The ensuing outrage’: Joachim von zur Gathen, ‘Zimmermann Telegram: The Original Draft’, Cryptologia (2007), vol. 31, pp. 2–37; David Kahn, ‘Edward Bell and His Zimmermann Telegram Memoranda’, Intelligence and National Security (1999), vol. 14 no. 3, pp. 143–59; TNA PRO HW 3/177 De Grey personal account of the breaking of the Zimmermann telegram.
Page 19 ‘Dilly’s future plaintive murmurs’: Penelope Fitzgerald, The Knox Brothers, Coward, McCann & Geoghegan, New York, 1977, p. 144.
Page 20 ‘There was great alarm’: see Beesly, Room 40, p. 25.
Page 21 ‘Dilly would marry Miss Roddam’: ibid., pp. 145–6.
Page 22 ‘Professor Walter Bruford’: CCAC Misc 20.
Page 23 ‘Willoughby, go and fetch the rum’: see Arthur J. Marder, From the Dreadnought to Scapa Flow: The Royal Navy in the Fisher Era 1904–1919, vol. 4: 1917: Year of Crisis, Oxford University Press, London, 1969, p. 265.
Page 24 ‘Alastair Denniston went out from ID25’: see Denniston, Thirty Secret Years, pp. 39–43.
Page 25 ‘My interpretation of Alice in ID25’: copies available from the Bletchley Park Trust.
Chapter 3: Alice in ID25
Page 1 ‘Peace, Peace, Oh for some peace…’: quoted in Patrick Beesly, Room 40: British Naval Intelligence 1914–18, Hamish Hamilton, London, 1982, p. 302.
Chapter 4: Between the wars
Page 1 ‘Its public function’: Robin Denniston, Thirty Secret Years: A.G. Denniston’s Work in Signals Intelligence 1914–1944, Polperro Heritage Press, Clifton-upon-Teme, 2007, p. 93.
Page 2 ‘Money was never a major consideration’: see Christopher Andrew, Secret Service: The Making of the British Intelligence Community, Heinemann, London, 1985, p. 259.
Page 3 ‘Working in blinkers’: TNA HW 25/12.
Page 4 ‘Sinclair moved the codebreakers’: see Michael Smith, The Spying Game: The Secret History of British Espionage, Politico’s, London, 2003, p. 259.
Page 5 ‘Our work has been done in the face of the enemy…’: quoted in Denniston, Thirty Secret Years, p. 48.
Page 6 ‘The inevitable had happened…’: Churchill College Archives, Cambridge, GBR/0014/CLKE, papers of William F. Clarke.
Page 7 ‘The task was finished in time’: see Denniston, Thirty Secret Years, p. 100.
Page 8 ‘Olive did not like living in Chelsea’: see Penelope Fitzgerald, The Knox Brothers, Coward, McCann & Geoghegan, New York, 1977, pp. 170–71.
Page 9 ‘Dilly caused some consternation’: ibid.
Page 10 ‘Sir John has bought an aeroplane…’: Oliver Knox, The Oldie, March 2002.
Page 11 ‘Just as Herodas…’: Herodas, The Mimes and Fragments, ed. A. D. Knox with notes by Walter Headlam, Cambridge University Press, Cambridge, 1922.
Page 12 ‘A glowing achievement’: W. G. Arnott, ‘Walter Headlam and Herodas’, Proceedings of the African Classical Association (1947), vol. 10.
Page 13 ‘Fetty, as we addressed him…’: quoted in Smith, The Spying Game, p. 260.
Page 14 ‘Signals intelligence, or Sigint’: see Denniston, Thirty Secret Years, p. 25.
Page 15 ‘The great Soviet plot’: see Smith, The Spying Game, p. 78.
Page 16 ‘A whole network of Russian intrigue was involved’: see Michael Smith and Ralph Erskine (eds), Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, Bantam, London, 2001, p. 26; Smith, The Spying Game, pp. 259–60.
Page 17 ‘The Russians lost no time in abandoning the cipher’: see Andrew, Secret Service, p. 332.
Page 18 ‘Knox had a very powerful intellect…’: quoted in Michael Smith, Station X: The Codebreakers of Bletchley Park, Channel 4 Books, London, 1998, p. 16.
Page 19 ‘Hungarian was successfully broken by Knox’: Denniston, Thirty Secret Years, p. 103.
Page 20 ‘John Tiltman … was recalled to England’: see Ralph Erskine and Peter Freeman, ‘Brigadier John Tiltman: One of Britain’s Finest Cryptologists’, Cryptologia (2003), vol. 27, p 293.
Page 21 ‘
The arrest of a number of Soviet agents’: See Smith and Erskine, Action This Day, pp. 28–31; Michael Smith, Foley: The Spy Who Saved 10,000 Jews, Politico’s, London, 2004, pp. 45–50; Gill Bennett, Churchill’s Man of Mystery: Desmond Morton and the World of Intelligence, Routledge, London, 2007, p. 191.
Page 22 ‘These were never publicised’: Denniston, Thirty Secret Years, p. 35.
Page 23 ‘Limericks are remembered long after White Papers’: quoted in Oliver Knox, obituary, The Times, 20 July 2002.
Page 24 ‘To his work he referred not at all…’: quoted in Fitzgerald, The Knox Brothers, pp. 170, 201.
Page 25 ‘Dilly got to know and like Christie’: see Evelyn Waugh, The Life of the Right Reverend Ronald Knox, Chapman & Hall, London, 1959, p. 189.
Page 26 ‘If Edgar Lobel was the most imposing…’: quoted in Fitzgerald, The Knox Brothers, p. 199.
Page 27 ‘[Dilly] used to amuse himself…’: quoted ibid., p. 198.
Page 28 ‘My father was talking of the frustrations of life…’: ibid., pp. 195–6, 203.
Page 29 ‘He would earn his place as a scholar’: see A. D. Knox, ‘The Early Iambers’, Philologus (1932), vol. 87. The use of syllable weight is critical to the metre of Greek classical poetry. The syllable weight depends upon the juxtaposition of the vowels and consonants within and around a syllable. A heavy syllable is known as a longum and a light syllable as a brevis. The law defined by Dilly, expanding on work carried out by Wilamowitz, is known as the ‘Wilamowitz–Knox bridge’. According to that law, ‘there may not be word end after the penultimate and also after the ante-penultimate longum’. See Seth L. Schein, The Iambic Trimeter in Aeschylus and Sophocles: A Study in Metrical Form, Brill, Leiden, 1979, p. 14.
Chapter 5: Enigma
Dilly Page 26