Origin and Nature of the Allied Cryptographic Advantage During World War II

1
Origin and Nature of the Allied Cryptographic
Advantage During World War II

• By
• Grant Musick

2
Enigma The WWII Encryption Gold Standard

• Enigma is short hand for an entire family of
  rotor based machines
• Used by the Germans and some other countries
• Used for commercial, diplomatic and military
  traffic
• Japanese used it to a lesser extent, but had own
  codes (JN-25 and PURPLE)

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Pre-War Activities

• There was a whole lot of spying going on by all
  countries
• U.S. identified Japan as a potential future
  adversary
• U.S. obtained Japanese naval code books
  throughout the 1920s
• U.S. sent naval personnel to Japan to learn
  Japanese language and culture.

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Pre-War Activities (cont)

• 1929 Poles obtained a mislabeled German Enigma
  machine.
• 1932 Marian Rejewsky breaks Enigma encrypted
  traffic
• 1938 Rejewsky creates a cryptologic bomb, an
  electro-mechanical device that helps test
  possibly Enigma keys

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Pre-War Activities (cont)

• In 1939 the Poles decide to share Enigma breaking
  techniques with British and French.
• Up until this point, British and French
  considered Enigma unbreakable.
• Without the Poles, Allied cryptanalysis would
  have been much, much harder.

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Sharing is Good

• Poles shared with British and French
• British shared with U.S.
• British established Bletchley Park so their
  cryptanalysts could share with each other
• U.S. forced Army and Navy to share code-breaking
  duties and glory for greater efficiency
• Axis didnt do this and paid the price

7
Smart People Victory

• British actively gathered intellectual talent at
  Bletchley Park e.g. Alan Turing
• U.S. administered I.Q. tests to likely recruits
  to see which ones might have talent in the signal
  services
• Axis didnt do this and paid the price

8
Industrialization Age of the Machine

• Cryptologic Bomb and Collossus computers enabled
  semi-automated code breaking
• U.S. Industrial might was key to churning out
  machines to break codes.

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The Joys of Gardening

• Allies held strategic initiative
• Made possible the use of dummy attacks to provoke
  radio traffic by Axis
• Military culture is very regimented, with
  procedures for everything
• So provoked traffic was analyzed against known
  responses to previous attacks.
• Known as gardening by the British

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The Joys of Fishing

• Allies made a concerted effort to capture Axis
  cryptographic machines
• Strategic initiative made this possible
• 15 Enigmas captured during the war seven from
  U-Boats and eight from surface vessels (spy
  trawlers and other covert merchant vessels)

11
Human Frailty

• People were as foolish then as they are today
• Axis operators didnt change keys frequently or
  used things like their initials or girlfriends
  names
• Axis operators also sent test messages using the
  same key, e.g. t, for the entire message

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In Closing

• After the war, American TICOM project teams
  found and detained a considerable number of
  German cryptographic personnel. Among the things
  the Americans learned was that German
  cryptographers, at least, understood very well
  that Enigma messages might be read they knew
  Enigma was not unbreakable. They just found it
  impossible to imagine anyone going to the immense
  effort required. When Abwehr personnel who had
  worked on Fish cryptography and Russian traffic
  were interned at Rosenheim around May 21, 1945,
  they were not at all surprised that Enigma had
  been broken, only that someone had mustered all
  the resources in time to actually do it. Admiral
  Dönitz had been advised that that was the least
  likely of all security problems.
• --From Answers.com Cryptanalysis of the Enigma