Erskine, Ralph. "Breaking Air Force and Army Enigma." In Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, eds. Ralph Erskine and Michael Smith, 47-76, 467-473. London and New York: Bantam, 2001.
1. "Breaking German Naval Enigma on Both Sides of the Atlantic." In Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, eds. Ralph Erskine and Michael Smith, 174-196, 482-488. London and New York: Bantam, 2001.
2. "The First Naval Enigma Decrypts of World War II." Cryptologia 21, no. 1 (Jan. 1997): 42-46.
This article includes both Erskine's commentary and reproductions of "the first text derived from naval Enigma signals" at Bletchley Park. The decrypts are part of the six days of traffic (22-27 April 1940) initially read by the British. It would be early August 1941 before Bletchley would be able to read the main cipher of the Kriegsmarine on an almost continuous basis.
3. "Kriegsmarine Short Signal Systems - And How Bletchley Park Exploited Them." Cryptologia 23, no. 1 (Jan. 1999): 65-92.
This article deals with those short signal systems that "were used by the British codebreakers in Hut 8 at Bletchley Park (BP) as cribs for breaking the two principal [German] naval Enigma ciphers," Heimische and Triton.
4. "Naval Enigma: An Astonishing Blunder." Intelligence and National Security 11, no. 3 (Jul. 1996): 468-473.
Message keys on the German naval Enigma cipher known as Süd, which was used in the Black Sea and Mediterranean, "were doubly enciphered until at least January 1944."
5. "Naval Enigma: The Breaking of Heimisch and Triton." Intelligence and National Security 3, no. 1 (Jan. 1988): 162-183.
6. "Naval Enigma: A Missing Link." International Journal of Intelligence and Counterintelligence 3, no. 4 (Winter 1989): 493-508.
Erskine believes that Hinsley's official history overstates the value of the "find" on U 110.
7. "The Soviets and Naval Enigma: Some Comments." Intelligence and National Security 4, no. 3 (Jul.1989): 503-511.
The article disputes the hypothesis in Geoff Jukes, "More on the Soviets and Ultra," Intelligence and National Security 3, no. 2 (Apr. 1988), 233-247, that the Soviets deciphered Admiral Dönitz' instructions (sometimes called the JW 55B message) to Scharnhorst (Rear Admiral Bey) on 25 December 1943 and that this indicates that the Soviets could break the Naval Enigma.
Erskine, Ralph. "Captured Kriegsmarine Enigma Documents at Bletchley Park." Cryptologia 32, no. 3 (Jul. 2008): 199-219.
Abstract: "This paper lists Enigma-related Kriegsmarine documents captured by the British during the Second World War and describes the formation and functions of Naval Section VI, which dealt with captured documents in the British Government Code and Cypher School."
Erskine, Ralph. "Enigma's Security: What the Germans Really Knew." In Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, eds. Ralph Erskine and Michael Smith, 370-385, 505-508. London and New York: Bantam, 2001.
Erskine, Ralph. "The Poles Reveal Their Secrets: Alastair Denniston's Account of the July 1939 Meeting at Pyry." Cryptologia 30, no. 4 (Oct. 2006): 294-305.
Erskine provides both the document and commentary on "the only British first-hand account of the historic meeting near Pyry, outside Warsaw, on 26 and 27 July 1939." (footnote omitted) He also includes a letter from Dillwyn Knox to Denniston about the meeting.
Erskine, Ralph. "Ralph Erskine Cracks Open a Tale of the Titans Who Won Key Battle." Times Higher Educational Supplement, 6 Oct. 2006, 24-25.
This article is a review of B. Jack Copeland, et al, COLOSSUS: The Secret of Bletchley Park's Codebreaking Computers (2006), but is worth reading beyond its review purpose for the substantive observations on Tunny that the author has included. Erskine notes that Tunny "was used mainly between the German High Command and army groups," and "provided more strategic intelligence than Enigma . Breaking Tunny traffic was the greatest code-breaking feat of the war. The US Army's reconstruction of Japan's Purple diplomatic cipher machine was comparable to Bletchley's solution of Tunny, but ascertaining Purple's daily settings was relatively simple, while finding Tunny's wheel patterns and settings required the highest cryptanalytic skills and involved advanced statistical techniques and some of the most complex electronic equipment of the war."
Erskine, Ralph. "Ultra Reveals a Late B-Dienst Success in the Atlantic." Cryptologia 34, no. 4 (Oct. 2010): 340-358.
Abstract: "This article describes a B-Dienst success in solving signals using a British code used by merchant ships (the Merchant Ships' Code (Mersigs II)) in late 1943, despite only having a depth of two; it also relates the history of the Mersigs II system."
Erskine, Ralph, and Peter Freeman. "Brigadier John Tiltman: One of Britain's Finest Cryptologists." Cryptologia 27, no. 4 (Oct. 2003): 289-318.
The authors term Tiltman "Bletchley Park's finest cryptanalyst on non-machine ciphers." He worked with GCCS/GCHQ from 1920 until his retirement in 1954, but then continued work with GCHQ until 1964. After that, he served as a researcher and consultant with NSA until 1980.
Erskine, Ralph, and Michael Smith, eds. Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer. London and New York: Bantam, 2001.
Beard, I&NS 18.1, says that Action This Day consists of "22 essays covering the BP story from the aftermath of World War I to the era of Cold War cooperation that BP's success made possible.... The editors provide short introductions to each essay, putting them in context." For Rohwer, JIH 2.1, this work contains "a great amount of new information on how things were achieved" at Bletchley Park. "Of special interest are the papers of the B.P. veterans, who reveal not only where they worked, but what they really did and how they achieved their successes."
To Stout, Studies 47.4 (2003), this "collection offers a pleasing combination of scholarship and memoirs." Kruh, Cryptologia 26.2, states flatly that this is "the best book ever written about codebreaking at Bletchley Park.... [C]hapters by some of Britain's outstanding historians, former codebreakers and academics (plus two Americans) ... trace the legacy of BP from the innovative work that led to the breaking of Enigma and other wartime codes, to the invention of modern computng and its influence on Cold War codebreaking."
Christensen, Cryptologia 35.3 (Jul. 2011), notes that The Bletchley Park Codebreakers "contains the material from Action This Day unchanged and includes one new chapter and three new appendices -- all written by former Bletchley Park codebreaker Edward Simpson."
Erskine, Ralph. "Wehrmacht Enigma Indicating Systems, Except the Kriegsmarine's Kenngruppenbuch System." In Action This Day: Bletchley Park from the Breaking of the Enigma Code to the Birth of the Modern Computer, eds. Ralph Erskine and Michael Smith, 444-448, 518. London and New York: Bantam, 2001.
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