Erskine, Ralph. "The Admiralty and Cipher Machines during the Second World War: Not So Stupid after All." Journal of Intelligence History 2, no 2 (Winter 2002): 49-68. [http://www.intelligence-history.org/jih/previous.html]
From abstract: "[T]he British official history of intelligence's claim that 'by 1939 the Admiralty had rejected the use of the [British cipher machine] Typex machine in ships' is categorically wrong -- only slow production prevented Typex entering service on ships.... The article explains why Typex (which was an improved version of commercial Enigma) was much more secure in practice than Wehrmacht Enigma, and describes the development of the Combined Cipher Machine (CCM) for joint use by the US, British, and Canadian navies. The CCM, and a post-war NATO version, are shown to have been very insecure, but wartime German codebreaking agencies could not break it."
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.
[UK/WWII/Ultra & Services/Navy]
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. "Churchill and the Start of the Ultra-Magic Deals." International Journal of Intelligence and Counterintelligence 10, no. 1 (Spring 1997): 57-74.
Erskine sucks dry available materials and concludes that "allegations of a double-cross or broken deal by 'perfidious Albion' [during the Sinkov mission in February and March 1941] are without the slightest foundation."
[CIA/Liaison; UK/WWII/Ultra; WWII/MAGIC][c]
Erskine, Ralph. "Eavesdropping on 'Bodden': ISOS v. the Abwehr in the Straits of Gibralter." Intelligence and National Security 12, no. 3 (Jul. 1997): 110-129.
"This article describes British efforts during the Second World War to counter an Abwehr ship-reporting organization in the Straits of Gibralter, known as the 'Bodden' line, which employed advanced infra-red equipment for night observation purposes."
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 Holden Agreement on Naval Sigint: The First BRUSA?" Intelligence and National Security 14, no. 2 (Summer 1999): 187-197.
The author suggests that the Holden Agreement of 2 October 1942 between the U.S. Navy and GCCS "probably has a stronger claim than BRUSA to being the forerunner of the UKUSA Agreement." It was the first agreement "to establish the special Sigint relationship between the two countries," and "it set the pattern for UKUSA, in that the United States was very much the senior partner in the alliance."
Erskine, Ralph. "The 1944 Naval BRUSA Agreement and Its Aftermath." Cryptologia 30, no. 1 (Jan. 2006): 1-22.
This article has substantial detail on how the U.S.-British agreements were implemented. Erskine concludes that "GCCS was, on the whole, disappointed with the arrangements for sharing Japanese naval Ultra during the war." He notes, however, that "[p]oor communication facilities on the British side badly held up the implementation of the Agreement." The article includes three appendices: "The BRUSA Agreement: 14th January 1944"; "An Agreement between G.C.&C.S. and Negat [OP-20-G] on Japanese Naval Cryptanalytic Tasks," dated 23 October 1944; and "Proposals Made to OP-20-G on 4th June 1945 for British Sigint Effort on S.E.A.C. [Mountbatten's South East Asia Command]."
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